Ever wondered how your sensitive messages stay secure in an increasingly dangerous digital landscape? The answer lies in message integrity controls, digital signatures, and certificate validation – the core components of modern cybersecurity we tackle in this episode.
We begin with a timely breakdown of Microsoft's recent security breach by Russian hackers who stole source code by exploiting a test environment. This real-world example perfectly illustrates why proper security controls must extend beyond production environments – a lesson many organizations learn too late.
Diving into the technical foundation of message security, we explore how basic checksums evolved into sophisticated hashing algorithms like MD5, SHA-2, and SHA-3. You'll understand what makes these algorithms effective at detecting tampering and why longer digests provide better protection against collision attacks.
Digital signatures emerge as the cornerstone of secure communication, providing the crucial trifecta of integrity verification, sender authentication, and non-repudiation. Through practical examples with our fictional users Alice and Bob, we demonstrate exactly how public and private keys work together to safeguard information exchange.
The episode culminates with an exploration of digital certificates and S/MIME protocols – the technologies that make secure email possible. You'll learn how certificate authorities establish chains of trust, what happens when certificates are compromised, and how the revocation process protects the entire ecosystem.
Whether you're preparing for the CISSP exam or simply want to understand how your sensitive communications remain protected, this episode provides clear, actionable knowledge about the cryptographic building blocks that secure our digital world.
Gain exclusive access to 360 FREE CISSP Practice Questions delivered directly to your inbox! Sign up at FreeCISSPQuestions.com and receive 30 expertly crafted practice questions every 15 days for the next 6 months—completely free! Don’t miss this valuable opportunity to strengthen your CISSP exam preparation and boost your chances of certification success. Join now and start your journey toward CISSP mastery today!
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Transcript
Episode Transcript
Available transcripts are automatically generated. Complete accuracy is not guaranteed.
Speaker 1 (00:00):
Welcome to the CISSP Cyber Training Podcast, where we
provide you the training andtools you need to pass the CISSP
exam the first time.
Hi, my name is Sean Gerber andI'm your host for this
action-packed, informativepodcast.
Join me each week as I providethe information you need to pass
the CISSP exam and grow yourcybersecurity knowledge.
(00:20):
Alright, let's get started,let's go cybersecurity knowledge
.
Speaker 2 (00:26):
All right, let's get started.
Hey, I'm Sean Gerber with CISSP, cyber Training, and today we
are going to be talking aboutsome various aspects around
message authenticity.
We're going to get into messageintegrity, controls, hashing
algorithms, we're going to getinto the overall piece of that,
digital signatures, digitalcertificates and finally, we're
going to get into what we callS-MIME.
Those are going to be thetopics for today's podcast.
(00:48):
Hope you guys are ready to hangon to this one.
This one's going to be a funone, but before we do, we're
going to get into one topic thatI saw from some news that was
in the news just yesterdayActually, it was released on
Friday is that Microsoftconfirms Russian hackers have
stole the source code andpotentially, some customer
secrets based on their testenvironment that they have
(01:09):
within their production and testaspects.
So this came to light on, Iguess, in January is where it
originally came out, but itsounds like the attack occurred
in November of 23.
Now, with that being said, itappears they leveraged a test
environment that Microsoft hadin place, for whatever reason
that they're testing theirproduction stuff, and they were
(01:32):
able to leverage it from apassword spraying model.
So it basically got someone'spassword and they compromised it
using known passwords that areprobably out on the internet
right now, and they were able tobreach this information.
Now, as they were able to getin there, it appears that they
were actually able to gainaccess to some of the source
code that Microsoft had withinthat test environment.
(01:53):
They didn't have multi-factorenabled because it was a test
environment, and I'm sorry, butthey're just going to have to do
better than this.
I mean, I've dealt withdevelopers in the past and one
of the things that we've had isyou have your production, you
have your test environment andin many cases, you have your
same source code that you use ina repository such as a GitLab,
github, and you end up havingthat that feeds into both of
(02:15):
those environments.
Well, when you leverage, if youdon't have the same level of
controls that you have on yourtest environment that you have
within your productionenvironment, now you're in a
situation where one they haveaccess in some cases maybe not
in this, but in some cases tothe various code repositories
that are available, because theyhave to do it in the test
(02:36):
environment to then push it intoproduction, and so it seems
like they didn't havemulti-factor enabled.
Well, having multi-factor andthen having bad passwords on
your test environment.
It's just a bad idea.
And that also shows thatthey're not enforcing any sort
of password complexity to thelevel that they do in their
(02:57):
production environment.
So there's a lot of tellinglittle breadcrumbs that are
built into there and, just likeanybody else, people get lazy.
They do.
And the people that are in thistest environment don't think
that it's just a testenvironment.
It's not like the fullproduction.
But one other thing is theytalked about in here with
customer data.
When I've seen in the pastwhere you'll have a test
(03:19):
environment set up, they willtake customer data specifically
from the production environmentand put it into their test
environment.
Maybe not all of it, butthey'll put a substantial amount
.
Why?
Because they want to make sureit works.
So if you're going to be ahacker, you're going to go after
these test environments,because what it can do is one,
give you a lot of greatinformation.
Two, it can also tell you a lotabout how the production
(03:42):
environment is laid out from anoverall structure standpoint,
and then in many cases, the samepasswords they're using in the
test environment are most likelybeing used pretty strongly in a
production environment.
So understand what happened here.
This is a pretty big deal, andit's from the APT29 folks that
are the fuzzy bear or the whatwas that?
(04:03):
They're the bears, I can'tremember the name of it.
But there's the APT29 folksthat are tied to the Russian
Foreign Intelligence Service, orotherwise known as their SVR.
These are the same folks thatwent after SolarWinds, and so it
is a pretty significant thingthat you can know that
Microsoft's just going to haveto do better at this, because I
come back to the point of let'slook at this from a critical
(04:26):
infrastructure standpoint, or asmall or medium-sized business
standpoint, which many of thecritical infrastructures are
within the United States.
A lot of them are using oldMicrosoft-type systems.
Many of them aren't updated,many of them may not even be
patched to the level they needto be, and so now you've got
access to the source code.
It's just bad, bad business andMicrosoft.
(04:48):
They make a lot of money.
They need to do a better job.
They have to do a better jobbecause so much of what they
have out there is tied to allthese systems, are all tied to
them, so something to keep inmind.
Again.
This comes down to.
This is the Russian hackersthat stole source code from the
Microsoft environment.
Okay, so now we're going to getinto the, for our podcast is
(05:11):
about today is message integritycontrols, or what we're going
to first start off with Now, amessage integrity check.
This is where it's designed andthis is a very basic level
version of this, where it'sdesigned to ensure the integrity
of a message between the timeit is created and the overall
time it is read.
Now the MIC works by creating arepresentation of the message
which is actually sent with themessage, and these integrity
(05:34):
checks are based upon moresimple math, but they're based
on the fact that they're goingto create this, this message
digest.
We're going to get into alittle bit more of a deeper
message digest, but they'regoing to create this second
message based on math, and thedesign is that its ultimate goal
is to ensure that the messagehas integrity when it goes from
point A to point B, but becauseof a basic message integrity
(05:57):
check, it is based on thissimple math.
There is the possibility youcould run into a collision,
which basically means there'stwo different message can have
the same representation of whatit created.
So let's kind of walk throughan example of how this works.
Now this is done through whatthey call a checksum.
So you have a cyclic redundancycheck or a CRC, and this is
(06:18):
that simple math that I talkedabout, where it performs this on
the block of data that's inthis message, such as a packet
or a file.
It'll create this, this CRCwill create this, what they call
a checksum, and this checksum.
So the CRC takes the simplemath let's just say, for example
, it takes your message and it'sgot Bill loves Frida loves
George, I don't know whateveryou want to say and you want to.
(06:39):
You has this message.
It then does this check on itand creates what they call a
checksum.
The message then performs thiscalculation and it sends it with
it.
Once they receive the message,it decrypts that piece of it and
it looks at that checksum fromthe same math and then, if they
match, it considers the messageto be nothing wrong with it,
(07:02):
that it was not compromised inany way, it was not corrupted in
any way.
That's the ultimate goal.
So if they're different, itpotentially could have been
tampered with or the overallmessage has been corrupted.
This is the simple piece ofthis.
It's called message integritycontrols.
Now, to take it up a notch,you'd go and you'd add in some
level of what they call ahashing algorithm.
(07:23):
Now, these hashing algorithmsis using complex encryption
technologies to create the sameconcept, but using it in a way
that is not easily tampered with.
It's not in a situation whereit would have be corrupted or
potentially run into collisions.
So these are much moresensitive to small bit changes
and therefore they are resistantto the collisions.
(07:45):
That doesn't mean that they aretotally benign from having a
collision, but they're much moreresistant from it and they work
really well as an integritycontrol for messages that are
being sent out.
Now, when you're talking hashingalgorithms, there's some key
concepts to understand.
About a hashing algorithm One,they have a fixed length digest.
(08:06):
So what does that mean?
It means the output of thehashing algorithm is always the
same length, so you're not goingto get some varying level links
when it comes to the hashingalgorithm.
So you have different types ofalgorithms that are of different
lengths.
But for an example, we'll useMD5.
Md5 hash always produces 128bit digest, which is basically
(08:27):
32 hexadecimal digits, right?
So the 32 times 4 is 128.
Now, that's an MD5 hash, butthat's a known digest that's
available for you.
So that's a fixed length digest.
It's also one way whichbasically means it's able to
easily compute the hash from onemessage, but it's very hard to
(08:48):
recover the message from thehash.
That doesn't mean you can't doit, but it's challenging.
You have a smaller digest.
It's easier I say easier, Ican't even do one plus one but
it's easier to recover the hashor the message from a hash
that's smaller.
The longer the hash, the harderthat is.
But what it basically comesright down to is that there's no
(09:11):
real good way to reverseengineer the original message
from the hash value, especiallybased on higher bit numbers.
Now, deterministic means thatthe same message always produces
the same hash.
So if you have the message thattalks about whatever it is, no
matter how many times you hashit, it will always come up with
the same overall digest.
(09:33):
No matter how many times youhash it, it'll always come up
with the same one, the samenumbers that will be there, the
same overall digest.
No matter how many times youhash it, it'll always come up
with the same one, the samenumbers that will be there, the
same 128 bits.
Okay, so the ultimate goal isthat it's going to be the same,
so that it can verify theintegrity and the authenticity
of the message so that it's nottampered with and modified.
So you want to ensure thatthat's the case and it does
calculate it on the entiremessage.
(09:54):
This means that the hash valuedepends on every bit of that
specific message, not just asmall part of it, like we talked
about earlier on the messageintegrity checks.
So when you're talking the hashit does the entire message.
The message integrity checkcould just take one piece of
that overall message andtherefore it's much more open to
have collisions.
It's much easier to not have agood potential message that's
(10:17):
sent out.
Now.
This property makes the hashesmore sensitive to changes,
obviously in the message, and itdoes resist against collisions
where there are two differentmessages that potentially could
produce the same hash.
That's a collision.
So I've had Bill has this longmessage that he sends and they
they hash it up and then Fredsends the long message that he
sends.
(10:37):
Those two message digest shouldnot match and that's a
collision if they would.
So therefore, that's how theMD5 hashes work.
They're also uniformlydistributed, which means that
the hash values are evenlyspread over all the possible
output space.
So there's no predictablepattern or there's no
correlation between them.
This produces the chances ofcollisions as well and it makes
(11:02):
it a much more secure and randomtype of environment.
Now there's some several popularhashing algorithms out there.
You got your MD5, which wementioned is 128-bit digest.
Sha-1 is 160.
You got your SHA-2 and 3, andthey have varying ranges of
their digest from 224 up to512-bit.
But MD-5, most people have beendeprecated to this point where
(11:23):
it doesn't really use an MD-5hash, but it was the staple that
was out there forever and youstill may see it.
So it's good for you to knowwhat an MD-5 hash is.
But in many cases now you'reexpecting to see SHA-2 and 3
hashes that are being usedwithin these environments.
So let's walk through anexample of how this could be
done within what you'd want toexpect to see, so the steps that
(11:46):
you would anticipate to see.
So, first off, you have Carol,okay, so she uploads a file to a
cloud storage service, right,and she wants to verify that has
not been corrupted or modifiedby anywhere else anyone else.
So she uses a hashing algorithmto generate a digest of the
file.
So she's got her file, myreport, and she creates an md5
(12:07):
or let's say, let's say, a shaw3 digest, so a shaw 3 digest.
She did it at 512 bits, so shewants to make sure that it is
really secure.
So she says this fixed length,one-way, deterministic and
uniformly distributed value,right?
So she's going to take thisthat's all the big terms right?
She's going to get that digest,she's going to get that form,
(12:29):
it's going to create a digest ofit.
It's going to create thishexadecimal number that's like
really long, and thishexadecimal number that's like
really long.
And then she's going to uploadthat file to the cloud storage
service.
Before she does, she takes anmd5 or I should say a sha3 hash.
She has that number, so shestores it.
She knows what that number is.
So now she wants to downloadthat file and check its
(12:50):
integrity to make sure that thefile that she uploaded is the
same one that she downloaded.
She wants to make sure of that.
She doesn't want to have asituation where maybe somebody
tampered with it.
So what she'll do then is shewill download the file and then
she will run the SHA-3 algorithmagainst it again and she
compares the digest from theoriginal one and the one that
(13:10):
she just did.
If they match, boom, she's inbusiness, they're the same.
If they don't match, thensomething has happened to that
file.
Now, as an example, you may seethis out there in the real world
.
Let's say you go to a filesharing site.
They will tell you what the MDor, depending on what they're
using, if it's MD5 or SHA,whatever it might be they'll
(13:31):
tell you what the hash should be.
So when you download that file,it should compare to what the
overall hash should be that'sdownloaded.
That's the expectation thatthey know.
That way, you know, someonedidn't go and put something into
that actual file that couldpotentially be malicious.
So that's the difference isunderstanding.
How do these digestives work.
And so if they match that's theultimate goal is that you then
(13:55):
can entrust the integrity ofthat specific file.
Okay, so now we're going to getinto digital signatures.
Now, a digital signature willprovide three different types of
services integrity,authenticity and repudiation, or
non-repudiation.
I should say Integrity, this isthe service that ensures a
message has not been tamperedwith or altered during the
(14:16):
transmission.
Okay, digital signatures, theseprovide three different
services.
You have integrity,authenticity and non-repudiation
.
So integrity, this is theservice that ensures that the
message has not been tamperedwith or altered during the
specific transmission.
So the digital signature canprovide integrity, basically
verifying the message digest,which we talked about earlier,
(14:38):
is computed by the receiver andmatches the one sent by the
sender.
This implies, obviously, themessage is intact, authentic and
has not been tampered.
The authenticity is a serviceby which a message originates
from the claimed sender and notfrom an imposter.
Digital signatures provideauthenticity using the sender's
private key.
So you have your private keyand you have a public key, and
(15:00):
the private key encrypts themessage digest, which can only
be decrypted by thecorresponding public key.
So you have your two keys outthere, a public and a private,
and only the private key can bedecrypted by the public key.
Now, in non-repudiation thisprevents the sender from denying
having sent the message or thereceiver from denying having
(15:21):
ever received it.
The digital signature willprovide the non-repudiation that
is needed by creating a uniqueand verifiable link between both
the message and the sender'sidentity.
So if you ever have a situationwhere someone would dispute it,
that's where the digitalsignature says no, it was signed
by you.
It's the same legal kind ofsignatures, legal significance
(15:42):
that you could have if you got apen and paper and you went and
signed it yourself.
So again, process of creating adigital signature is quite easy,
and it fundamentally involvestwo specific steps.
The sender hashes a message andproduces a fixed length message
digest, like we talked aboutearlier, and then the sender
encrypts the hash value with thesender's private key.
(16:02):
Once that's done, then therecipient will then decrypt the
hash value of the sender'sprivate public key, and then the
recipient hashes the messageand compares the result to the
decrypted hash value.
Okay, if they match, thenyou're in business.
Right, that's the ultimate goal.
So let's kind of give you anexample of how this would work.
So you have Alice and you haveBob.
(16:23):
Alice wants to send a messageto Bob.
Alice has the message, shesigns it with her private key.
The key thing here to rememberis that your private key should
never be compromised.
The moment your private key iscompromised, then all of this
goes out the window.
So this is something that'svery important to be kept within
your system, and this is alldone automatically.
(16:47):
But it is probably one of themost important aspects that you
need to ensure remainsconsistent is your private key
is never compromised.
The public key, on the otherhand, is out there on the
internet and is available foranybody's use.
But the goal is that it canbegin this part of communication
back and forth between the twoentities.
So Alice, again, she has thismessage and she wants to send it
to Bob and she sends it withher private key.
(17:09):
She uses the hash function togenerate a hash value which has
the fixed length of stringswhich talked about earlier and
it has unique representation ofthat specific message.
She then encrypts the hashvalue with her private key,
forming the digital signature.
They then attach the digitalsignature to the message and
it's sent to Bob.
Bob receives the message andwith the digital signature it's
(17:32):
already attached from Alice.
So if he wants to verify thiscame from Alice and that it
hasn't been tampered with, hetakes Alice's public key,
decrypts the digital signature,he gets a hash value that Alice
generated.
He also uses the same hashfunction to hash the overall
message that was sent andthey're basically producing
another hash.
So you have two hashes the onethat was encrypted as a digital
(17:55):
signature and the other onewhich is the actual message
itself.
You compare the two and if theyboth match, then at that point
in time you can say that it wasnot compromised and it's
legitimate.
So it's a really simple process, but there's a lot of little
moving parts which makes it kindof complicated and confusing.
But just remember, you have,like we talked about, you have
your hashing function, like aSHA, you have your private and
(18:19):
public keys and then you havethe overall digital signature
itself.
That comes from what we call amessage digest.
That's created.
Okay, so let's roll into whatare digital certificates Now.
Digital certificates bind anindividual to their public key
key and all certificateauthorities confirm that.
They call it.
An x 509 certificate is thespecific standard.
(18:40):
So you're going to be dealingwith some different types of
terms.
Now that come out of thecertificates, you're going to
have what they call a rootcertificate authority or root ca
.
These are considered what theycall the root of trust or the
trust anchor, and they're thefoundation of all digital
certificates that are out there.
Each of the major brands havethese the Microsofts, the
(19:01):
GoDaddys.
They have what they call.
They consider what they call aroot certificate or a
certificate authority.
Many of the hackers would loveto go after the certificate
authorities, and they do,because the ultimate goal is, if
you can get that certificateauthority capability, you now
can sign whatever you want froma digital certificate standpoint
, and in the past, there's beenvarious situations that have
(19:21):
occurred where the root CAs havebeen compromised.
Now there's intermediate CAswho can also sign certificates
and can issue these, but theyhave a very strict process by
which they have to become acertificate authority.
Now, digital certificates, bestpractice suggests when a public
and private key pairs areperiodically replaced.
That is usually the best thingthat's associated with a digital
(19:43):
certificate.
That's especially when adigital certificate is also
replaced.
You want to ensure that yourpublic and private keys are
replaced.
Now, when a private key hasbeen compromised, a digital
certificate should be revoked asquickly as possible, and it's
happened in the past whereyou've had to have a revocation
plan in place for these keys.
Now there's basically areplacement revocation process
(20:07):
and we'll kind of walk youthrough those how that happens.
Now, when it comes toreplacement, there's regular
replacement of expiredcertificates.
These replacement certificatesare issued are associated with
private keys that havepotentially been compromised.
Well, the CAs will have arevocation process by which
they're going to give you areplacement certificate.
(20:28):
The client will download andsearch all the list of serial
numbers of revoked certificatesfrom the CA.
The client queries the CA forrevocation status of the
specific certificate and theirserial number that's tied with
this.
So this is a manual processthat you can do or the system
will do it for you.
Some people that are veryinterested into this.
(20:48):
They will actually go out andmanually do this process, but
the computer itself will go outand compare your digital
certificates based on ones thatpotentially have been revocated.
So you don't have to go throughthis entire process.
But it's important to know,especially when you're dealing
with web servers.
They'll wanna make sure thatyour certificate is a legitimate
and up-to-date certificate andif not, they're gonna want to
(21:10):
get you a new one.
So let me walk through aprocess of how this would happen
.
So you have a digitalcertificate that and Alice owns
a public key for encrypting andsigning messages.
Now the information that's inthis digital certificate has the
name and the public key ofAlice, the name and the
(21:31):
signature of the intermediate,ca, and the serial number and
expiration date of thecertificate itself.
Specifically, it talks aboutthe purpose of this certificate
for, whether it's for signingdocuments, whatever it might be,
and then the potential scopefor it.
The XO5 standard has variousversions and extensions that tie
into this as well.
So the digital certificate thatis tied to Alice can be
(21:52):
validated by checking thesignature of the intermediate CA
against the public key, whichis obtained, obviously, from the
root CA certificate.
The digital certificate thencan be revoked by the CA if her
private key, if Alice's privatekey, is potentially compromised
or if she violates the terms ofthe certificate itself, using it
for something it shouldn't be.
This digital certificate canalso be renewed by the
(22:16):
intermediate CA before itspecifically expires and I've
had to do this myself where youcan actually go out and get a
new digital certificate beforeit actually goes out.
Most of the time this is done,like I said, automatically it
will do this for you, but youcan actually manually go and do
this process as well.
Once this happens, this digitalcertificate is then pinned
(22:36):
directly to Alice, who it trusts, and the client does not have
the ability to do anything withit.
It validates the certificateevery time it communicates with
Alice and it verifies that iswho she specifically is.
Now let's kind of walk throughthe the life cycle of a digital
certificate.
So we have enrollment, so Aliceagain requests a certificate
from the intermediate CA toprovide her identity and her
(22:59):
public key.
So obviously we talked aboutintermediate CAs.
You have your root C and thenyou have your intermediate CAs
Most various companies.
There's lots of intermediateCAs out there.
You can actually get that listoff your computer.
You can understand who are allof the authorities that are tied
to your certificates on yourcomputer.
That can all be looked at,depending on what version you
(23:20):
have and where it's locatedwhether it's Windows, whether
it's Linux or whether it'sactually in a mic or a apple
type version.
Now the intermediate ca willverify alice's identity and her
public key and then issues acertificate to her.
A client who wants tocommunicate with alice will
validate her certificate bychecking the signature of the
(23:40):
intermediate ca and theexpiration of the overall
certificate.
Then if that becomes a problemand she has to revocate or
revoke to get the certificaterevoked, the intermediate CA
will then revoke her certificateif her private key is ever
compromised and they're aware ofthat, or if she obviously
violates the terms of service.
And then that's part of whatthey call a CRL, which is your
(24:01):
Certificate Revocation List.
There's also an online versionof this called the Online
Certificate Status Protocol,ocsp.
That's a server that's outthere that will look for these
certificates as well and then,once that occurs, the
intermediate CA will renewAlice's certificate before it
expires or, if it has beencompromised, they'll renew that
(24:21):
as well, depending upon whatoccurred and why it was actually
compromised.
So, again, these certificatesare an important factor, digital
certificates are, and you havevarious pieces of this as it
relates to how you're going tohandle the certificate for your
specific identity.
Last thing we're going to getinto is SMIME.
So SMIME is a standard forpublic key encryption that
(24:43):
provides security services fordigital messaging applications.
Now it originally starts off.
It's tied into PKI, which isyour public key infrastructure.
Now the basic security servicesthat are with S-MIME are
authentication, non-repudiationof the origin, message integrity
and then confidentiality.
Now S-MIME is a culmination ofwhat started off as MIME.
(25:05):
So we're talking MIME.
It's M-I-M-E, so Mike India,mike Echo.
Now MIME did not addresssecurity issues.
It was just basically developedfor messages.
But as time has gone on, thereneeded to be some level of
security added to this overallstandard.
So they created what they calla S-slash slash MIME, which adds
features to your emailmessaging, including the digital
(25:27):
signatures which we talkedabout encryption for message
privacy and then, obviously,hashing for message integrity
and non-repudiation.
So that's where the S MIMEcomes into play.
Now an example of an S MIME.
We'll kind of get put this intoaction again.
Is?
We got Alice and Bob.
Now Alice wants to send themessage, a secure message, to
Bob, who has her public key, andhe has this public key from a
(25:49):
certificate issued by a trustedCA right.
So Alice uses Bob's public keyto encrypt the message content
and generate what he, what she,what she calls.
What they call is a messagedigest we talked about earlier,
which hashes the message.
Alice then signs the messagedigest with her own private key,
creating a digital signaturethat proves her identity as the
(26:14):
sender and prevents anyone fromaltering the message.
Alice then takes and attachesher public key certificate and
Bob's public key certificate tothe email, along with the
encrypted message and thedigital signature.
So you got four things in placehere Alice's public key, bob's
public key, the message itselfthat's encrypted, and the
(26:34):
digital signature.
Alice will then send the emailto Bob using standard MIME
format, but with a secure MIMEheader indicating that the
security features have been used.
So that's the key piece of thisis that it's a MIME message,
mime header indicating that thesecurity features have been used
.
So that's the key piece of thisis that it's a MIME message,
mime format, but it's a slash Sslash MIME to show you that the
security features have been used.
(26:55):
Specifically, Bob receives thisemail and then verifies the
certificates with the CA,ensuring that they're valid and
then that they have been revoked.
And then Bob uses his ownprivate key, which is in
compromise, to decrypt themessage content and Alice's
public key to verify hersignature.
So you got Alice's public keyto verify the signature.
You got Bob's private key todecrypt the message because he
(27:18):
used his public key, and thenalso to verify the digital
signature and the message digestconfirming Alice's identity and
the message integrity.
Bob uses his own private key todecrypt the message and then
Alice's public key to verify thedigital signature and the
message digest.
So that verifies that Alice iswho she says she is.
(27:38):
Bob can read the message andreply to Alice using the same
procedure, going backwards or ifhe uses a different security
protocol, if he chooses.
The bottom line is again, we'llwalk this through one more time.
Alice wants to send a messageto Bob the secure message who
has a public key certificatethat's issued out there on the
internet by a trusted CA.
(27:59):
Alice uses Bob's public key, soshe takes his public key, she
encrypts the message content andgenerates a message digest Okay
.
So that's again.
That's the hash.
That's the hash of the overallmessage itself.
Alice signs the message digestthat she was just created with
her own private key.
So the private key she owns noone else has.
(28:20):
She then signs it with that,creating a digital signature
that proves she is who she saysshe is.
She then sends this, or sheattaches the public key
certificate okay, that Bob'spublic key to the email, along
with the encrypted message andthe digital signature that she
created.
She sends this to Bob throughan email using standard MIME
(28:43):
format with an S slash header,to Bob through an email using
standard MIME format with an Sslash header.
And then Bob receives the emailand verifies that the
certificate with the CA.
So her certificate is confirmedwith the CA, ensuring that
they're valid and it hasn't beenrevoked.
Bob then uses his own privatekey to decrypt the message.
He's got a private key, it'sbeen encrypted with his public
key.
It's now verifies the message.
(29:04):
So the message is unencrypted,but then he's able to utilize
Alice's public key, which is outon the internet, to verify her
digital signature and themessage digest are correct.
So then they're both equal.
So that hasn't had anythingthat's happened to the message
digest at all.
It's all there and then Bob canread the message and obviously
reply to her as he sees fit.
(29:25):
So that is the overall exampleof an S-MIME.
Speaker 1 (29:28):
Okay, that's all I have for you today.
I hope you all have a wonderfulday.
Speaker 2 (29:32):
Head on over to CISSP Cyber Training and catch out
what we got.
All these videos are there freefor you to gain access to.
They're on the blog.
You can go check them out.
Also, if you're interested, Ihave some paid products out
there as well for you.
To help you pass the CISSP thefirst time, I have a blueprint.
That's amazing.
Everybody that uses it passes.
They are doing a great job withthis.
If they follow what theblueprint offers, you will pass
(29:56):
the CISSP exam.
If you're interested in justgetting the free content, it's
there and available for you aswell.
All of that is there at CISSPCyber Training.
Go check it outcisspcybertrainingcom.
Check it out.
Let me know.
If you have any questions atall.
Feel free to respond to me inthe.
There's different places.
(30:17):
You can reply to me or just letme know what you need, but I'm
here for you at that CISSP CyberTraining.
Head on over there, check itout.
Also, you can get 30 or 60 freeCISSP questions.
Just go tofreecisspquestionscom and you
can get answers to those as well.
All right, have a wonderful dayand we will catch you on the
flip side, see ya.
Welcome to the CISSP Cyber Training Podcast, where we
provide you the training andtools you need to pass the CISSP
exam the first time.
Hi, my name is Sean Gerber andI'm your host for this
action-packed, informativepodcast.
Join me each week as I providethe information you need to pass
the CISSP exam and grow yourcybersecurity knowledge.
(00:20):
Alright, let's get started,let's go cybersecurity knowledge
.
Speaker 2 (00:26):
All right, let's get started.
Hey, I'm Sean Gerber with CISSP, cyber Training, and today we
are going to be talking aboutsome various aspects around
message authenticity.
We're going to get into messageintegrity, controls, hashing
algorithms, we're going to getinto the overall piece of that,
digital signatures, digitalcertificates and finally, we're
going to get into what we callS-MIME.
Those are going to be thetopics for today's podcast.
(00:48):
Hope you guys are ready to hangon to this one.
This one's going to be a funone, but before we do, we're
going to get into one topic thatI saw from some news that was
in the news just yesterdayActually, it was released on
Friday is that Microsoftconfirms Russian hackers have
stole the source code andpotentially, some customer
secrets based on their testenvironment that they have
(01:09):
within their production and testaspects.
So this came to light on, Iguess, in January is where it
originally came out, but itsounds like the attack occurred
in November of 23.
Now, with that being said, itappears they leveraged a test
environment that Microsoft hadin place, for whatever reason
that they're testing theirproduction stuff, and they were
(01:32):
able to leverage it from apassword spraying model.
So it basically got someone'spassword and they compromised it
using known passwords that areprobably out on the internet
right now, and they were able tobreach this information.
Now, as they were able to getin there, it appears that they
were actually able to gainaccess to some of the source
code that Microsoft had withinthat test environment.
(01:53):
They didn't have multi-factorenabled because it was a test
environment, and I'm sorry, butthey're just going to have to do
better than this.
I mean, I've dealt withdevelopers in the past and one
of the things that we've had isyou have your production, you
have your test environment andin many cases, you have your
same source code that you use ina repository such as a GitLab,
github, and you end up havingthat that feeds into both of
(02:15):
those environments.
Well, when you leverage, if youdon't have the same level of
controls that you have on yourtest environment that you have
within your productionenvironment, now you're in a
situation where one they haveaccess in some cases maybe not
in this, but in some cases tothe various code repositories
that are available, because theyhave to do it in the test
(02:36):
environment to then push it intoproduction, and so it seems
like they didn't havemulti-factor enabled.
Well, having multi-factor andthen having bad passwords on
your test environment.
It's just a bad idea.
And that also shows thatthey're not enforcing any sort
of password complexity to thelevel that they do in their
(02:57):
production environment.
So there's a lot of tellinglittle breadcrumbs that are
built into there and, just likeanybody else, people get lazy.
They do.
And the people that are in thistest environment don't think
that it's just a testenvironment.
It's not like the fullproduction.
But one other thing is theytalked about in here with
customer data.
When I've seen in the pastwhere you'll have a test
(03:19):
environment set up, they willtake customer data specifically
from the production environmentand put it into their test
environment.
Maybe not all of it, butthey'll put a substantial amount
.
Why?
Because they want to make sureit works.
So if you're going to be ahacker, you're going to go after
these test environments,because what it can do is one,
give you a lot of greatinformation.
Two, it can also tell you a lotabout how the production
(03:42):
environment is laid out from anoverall structure standpoint,
and then in many cases, the samepasswords they're using in the
test environment are most likelybeing used pretty strongly in a
production environment.
So understand what happened here.
This is a pretty big deal, andit's from the APT29 folks that
are the fuzzy bear or the whatwas that?
(04:03):
They're the bears, I can'tremember the name of it.
But there's the APT29 folksthat are tied to the Russian
Foreign Intelligence Service, orotherwise known as their SVR.
These are the same folks thatwent after SolarWinds, and so it
is a pretty significant thingthat you can know that
Microsoft's just going to haveto do better at this, because I
come back to the point of let'slook at this from a critical
(04:26):
infrastructure standpoint, or asmall or medium-sized business
standpoint, which many of thecritical infrastructures are
within the United States.
A lot of them are using oldMicrosoft-type systems.
Many of them aren't updated,many of them may not even be
patched to the level they needto be, and so now you've got
access to the source code.
It's just bad, bad business andMicrosoft.
(04:48):
They make a lot of money.
They need to do a better job.
They have to do a better jobbecause so much of what they
have out there is tied to allthese systems, are all tied to
them, so something to keep inmind.
Again.
This comes down to.
This is the Russian hackersthat stole source code from the
Microsoft environment.
Okay, so now we're going to getinto the, for our podcast is
(05:11):
about today is message integritycontrols, or what we're going
to first start off with Now, amessage integrity check.
This is where it's designed andthis is a very basic level
version of this, where it'sdesigned to ensure the integrity
of a message between the timeit is created and the overall
time it is read.
Now the MIC works by creating arepresentation of the message
which is actually sent with themessage, and these integrity
(05:34):
checks are based upon moresimple math, but they're based
on the fact that they're goingto create this, this message
digest.
We're going to get into alittle bit more of a deeper
message digest, but they'regoing to create this second
message based on math, and thedesign is that its ultimate goal
is to ensure that the messagehas integrity when it goes from
point A to point B, but becauseof a basic message integrity
(05:57):
check, it is based on thissimple math.
There is the possibility youcould run into a collision,
which basically means there'stwo different message can have
the same representation of whatit created.
So let's kind of walk throughan example of how this works.
Now this is done through whatthey call a checksum.
So you have a cyclic redundancycheck or a CRC, and this is
(06:18):
that simple math that I talkedabout, where it performs this on
the block of data that's inthis message, such as a packet
or a file.
It'll create this, this CRCwill create this, what they call
a checksum, and this checksum.
So the CRC takes the simplemath let's just say, for example
, it takes your message and it'sgot Bill loves Frida loves
George, I don't know whateveryou want to say and you want to.
(06:39):
You has this message.
It then does this check on itand creates what they call a
checksum.
The message then performs thiscalculation and it sends it with
it.
Once they receive the message,it decrypts that piece of it and
it looks at that checksum fromthe same math and then, if they
match, it considers the messageto be nothing wrong with it,
(07:02):
that it was not compromised inany way, it was not corrupted in
any way.
That's the ultimate goal.
So if they're different, itpotentially could have been
tampered with or the overallmessage has been corrupted.
This is the simple piece ofthis.
It's called message integritycontrols.
Now, to take it up a notch,you'd go and you'd add in some
level of what they call ahashing algorithm.
(07:23):
Now, these hashing algorithmsis using complex encryption
technologies to create the sameconcept, but using it in a way
that is not easily tampered with.
It's not in a situation whereit would have be corrupted or
potentially run into collisions.
So these are much moresensitive to small bit changes
and therefore they are resistantto the collisions.
(07:45):
That doesn't mean that they aretotally benign from having a
collision, but they're much moreresistant from it and they work
really well as an integritycontrol for messages that are
being sent out.
Now, when you're talking hashingalgorithms, there's some key
concepts to understand.
About a hashing algorithm One,they have a fixed length digest.
(08:06):
So what does that mean?
It means the output of thehashing algorithm is always the
same length, so you're not goingto get some varying level links
when it comes to the hashingalgorithm.
So you have different types ofalgorithms that are of different
lengths.
But for an example, we'll useMD5.
Md5 hash always produces 128bit digest, which is basically
(08:27):
32 hexadecimal digits, right?
So the 32 times 4 is 128.
Now, that's an MD5 hash, butthat's a known digest that's
available for you.
So that's a fixed length digest.
It's also one way whichbasically means it's able to
easily compute the hash from onemessage, but it's very hard to
(08:48):
recover the message from thehash.
That doesn't mean you can't doit, but it's challenging.
You have a smaller digest.
It's easier I say easier, Ican't even do one plus one but
it's easier to recover the hashor the message from a hash
that's smaller.
The longer the hash, the harderthat is.
But what it basically comesright down to is that there's no
(09:11):
real good way to reverseengineer the original message
from the hash value, especiallybased on higher bit numbers.
Now, deterministic means thatthe same message always produces
the same hash.
So if you have the message thattalks about whatever it is, no
matter how many times you hashit, it will always come up with
the same overall digest.
(09:33):
No matter how many times youhash it, it'll always come up
with the same one, the samenumbers that will be there, the
same overall digest.
No matter how many times youhash it, it'll always come up
with the same one, the samenumbers that will be there, the
same 128 bits.
Okay, so the ultimate goal isthat it's going to be the same,
so that it can verify theintegrity and the authenticity
of the message so that it's nottampered with and modified.
So you want to ensure thatthat's the case and it does
calculate it on the entiremessage.
(09:54):
This means that the hash valuedepends on every bit of that
specific message, not just asmall part of it, like we talked
about earlier on the messageintegrity checks.
So when you're talking the hashit does the entire message.
The message integrity checkcould just take one piece of
that overall message andtherefore it's much more open to
have collisions.
It's much easier to not have agood potential message that's
(10:17):
sent out.
Now.
This property makes the hashesmore sensitive to changes,
obviously in the message, and itdoes resist against collisions
where there are two differentmessages that potentially could
produce the same hash.
That's a collision.
So I've had Bill has this longmessage that he sends and they
they hash it up and then Fredsends the long message that he
sends.
(10:37):
Those two message digest shouldnot match and that's a
collision if they would.
So therefore, that's how theMD5 hashes work.
They're also uniformlydistributed, which means that
the hash values are evenlyspread over all the possible
output space.
So there's no predictablepattern or there's no
correlation between them.
This produces the chances ofcollisions as well and it makes
(11:02):
it a much more secure and randomtype of environment.
Now there's some several popularhashing algorithms out there.
You got your MD5, which wementioned is 128-bit digest.
Sha-1 is 160.
You got your SHA-2 and 3, andthey have varying ranges of
their digest from 224 up to512-bit.
But MD-5, most people have beendeprecated to this point where
(11:23):
it doesn't really use an MD-5hash, but it was the staple that
was out there forever and youstill may see it.
So it's good for you to knowwhat an MD-5 hash is.
But in many cases now you'reexpecting to see SHA-2 and 3
hashes that are being usedwithin these environments.
So let's walk through anexample of how this could be
done within what you'd want toexpect to see, so the steps that
(11:46):
you would anticipate to see.
So, first off, you have Carol,okay, so she uploads a file to a
cloud storage service, right,and she wants to verify that has
not been corrupted or modifiedby anywhere else anyone else.
So she uses a hashing algorithmto generate a digest of the
file.
So she's got her file, myreport, and she creates an md5
(12:07):
or let's say, let's say, a shaw3 digest, so a shaw 3 digest.
She did it at 512 bits, so shewants to make sure that it is
really secure.
So she says this fixed length,one-way, deterministic and
uniformly distributed value,right?
So she's going to take thisthat's all the big terms right?
She's going to get that digest,she's going to get that form,
(12:29):
it's going to create a digest ofit.
It's going to create thishexadecimal number that's like
really long, and thishexadecimal number that's like
really long.
And then she's going to uploadthat file to the cloud storage
service.
Before she does, she takes anmd5 or I should say a sha3 hash.
She has that number, so shestores it.
She knows what that number is.
So now she wants to downloadthat file and check its
(12:50):
integrity to make sure that thefile that she uploaded is the
same one that she downloaded.
She wants to make sure of that.
She doesn't want to have asituation where maybe somebody
tampered with it.
So what she'll do then is shewill download the file and then
she will run the SHA-3 algorithmagainst it again and she
compares the digest from theoriginal one and the one that
(13:10):
she just did.
If they match, boom, she's inbusiness, they're the same.
If they don't match, thensomething has happened to that
file.
Now, as an example, you may seethis out there in the real world
.
Let's say you go to a filesharing site.
They will tell you what the MDor, depending on what they're
using, if it's MD5 or SHA,whatever it might be they'll
(13:31):
tell you what the hash should be.
So when you download that file,it should compare to what the
overall hash should be that'sdownloaded.
That's the expectation thatthey know.
That way, you know, someonedidn't go and put something into
that actual file that couldpotentially be malicious.
So that's the difference isunderstanding.
How do these digestives work.
And so if they match that's theultimate goal is that you then
(13:55):
can entrust the integrity ofthat specific file.
Okay, so now we're going to getinto digital signatures.
Now, a digital signature willprovide three different types of
services integrity,authenticity and repudiation, or
non-repudiation.
I should say Integrity, this isthe service that ensures a
message has not been tamperedwith or altered during the
(14:16):
transmission.
Okay, digital signatures, theseprovide three different
services.
You have integrity,authenticity and non-repudiation
.
So integrity, this is theservice that ensures that the
message has not been tamperedwith or altered during the
specific transmission.
So the digital signature canprovide integrity, basically
verifying the message digest,which we talked about earlier,
(14:38):
is computed by the receiver andmatches the one sent by the
sender.
This implies, obviously, themessage is intact, authentic and
has not been tampered.
The authenticity is a serviceby which a message originates
from the claimed sender and notfrom an imposter.
Digital signatures provideauthenticity using the sender's
private key.
So you have your private keyand you have a public key, and
(15:00):
the private key encrypts themessage digest, which can only
be decrypted by thecorresponding public key.
So you have your two keys outthere, a public and a private,
and only the private key can bedecrypted by the public key.
Now, in non-repudiation thisprevents the sender from denying
having sent the message or thereceiver from denying having
(15:21):
ever received it.
The digital signature willprovide the non-repudiation that
is needed by creating a uniqueand verifiable link between both
the message and the sender'sidentity.
So if you ever have a situationwhere someone would dispute it,
that's where the digitalsignature says no, it was signed
by you.
It's the same legal kind ofsignatures, legal significance
(15:42):
that you could have if you got apen and paper and you went and
signed it yourself.
So again, process of creating adigital signature is quite easy,
and it fundamentally involvestwo specific steps.
The sender hashes a message andproduces a fixed length message
digest, like we talked aboutearlier, and then the sender
encrypts the hash value with thesender's private key.
(16:02):
Once that's done, then therecipient will then decrypt the
hash value of the sender'sprivate public key, and then the
recipient hashes the messageand compares the result to the
decrypted hash value.
Okay, if they match, thenyou're in business.
Right, that's the ultimate goal.
So let's kind of give you anexample of how this would work.
So you have Alice and you haveBob.
(16:23):
Alice wants to send a messageto Bob.
Alice has the message, shesigns it with her private key.
The key thing here to rememberis that your private key should
never be compromised.
The moment your private key iscompromised, then all of this
goes out the window.
So this is something that'svery important to be kept within
your system, and this is alldone automatically.
(16:47):
But it is probably one of themost important aspects that you
need to ensure remainsconsistent is your private key
is never compromised.
The public key, on the otherhand, is out there on the
internet and is available foranybody's use.
But the goal is that it canbegin this part of communication
back and forth between the twoentities.
So Alice, again, she has thismessage and she wants to send it
to Bob and she sends it withher private key.
(17:09):
She uses the hash function togenerate a hash value which has
the fixed length of stringswhich talked about earlier and
it has unique representation ofthat specific message.
She then encrypts the hashvalue with her private key,
forming the digital signature.
They then attach the digitalsignature to the message and
it's sent to Bob.
Bob receives the message andwith the digital signature it's
(17:32):
already attached from Alice.
So if he wants to verify thiscame from Alice and that it
hasn't been tampered with, hetakes Alice's public key,
decrypts the digital signature,he gets a hash value that Alice
generated.
He also uses the same hashfunction to hash the overall
message that was sent andthey're basically producing
another hash.
So you have two hashes the onethat was encrypted as a digital
(17:55):
signature and the other onewhich is the actual message
itself.
You compare the two and if theyboth match, then at that point
in time you can say that it wasnot compromised and it's
legitimate.
So it's a really simple process, but there's a lot of little
moving parts which makes it kindof complicated and confusing.
But just remember, you have,like we talked about, you have
your hashing function, like aSHA, you have your private and
(18:19):
public keys and then you havethe overall digital signature
itself.
That comes from what we call amessage digest.
That's created.
Okay, so let's roll into whatare digital certificates Now.
Digital certificates bind anindividual to their public key
key and all certificateauthorities confirm that.
They call it.
An x 509 certificate is thespecific standard.
(18:40):
So you're going to be dealingwith some different types of
terms.
Now that come out of thecertificates, you're going to
have what they call a rootcertificate authority or root ca
.
These are considered what theycall the root of trust or the
trust anchor, and they're thefoundation of all digital
certificates that are out there.
Each of the major brands havethese the Microsofts, the
(19:01):
GoDaddys.
They have what they call.
They consider what they call aroot certificate or a
certificate authority.
Many of the hackers would loveto go after the certificate
authorities, and they do,because the ultimate goal is, if
you can get that certificateauthority capability, you now
can sign whatever you want froma digital certificate standpoint
, and in the past, there's beenvarious situations that have
(19:21):
occurred where the root CAs havebeen compromised.
Now there's intermediate CAswho can also sign certificates
and can issue these, but theyhave a very strict process by
which they have to become acertificate authority.
Now, digital certificates, bestpractice suggests when a public
and private key pairs areperiodically replaced.
That is usually the best thingthat's associated with a digital
(19:43):
certificate.
That's especially when adigital certificate is also
replaced.
You want to ensure that yourpublic and private keys are
replaced.
Now, when a private key hasbeen compromised, a digital
certificate should be revoked asquickly as possible, and it's
happened in the past whereyou've had to have a revocation
plan in place for these keys.
Now there's basically areplacement revocation process
(20:07):
and we'll kind of walk youthrough those how that happens.
Now, when it comes toreplacement, there's regular
replacement of expiredcertificates.
These replacement certificatesare issued are associated with
private keys that havepotentially been compromised.
Well, the CAs will have arevocation process by which
they're going to give you areplacement certificate.
(20:28):
The client will download andsearch all the list of serial
numbers of revoked certificatesfrom the CA.
The client queries the CA forrevocation status of the
specific certificate and theirserial number that's tied with
this.
So this is a manual processthat you can do or the system
will do it for you.
Some people that are veryinterested into this.
(20:48):
They will actually go out andmanually do this process, but
the computer itself will go outand compare your digital
certificates based on ones thatpotentially have been revocated.
So you don't have to go throughthis entire process.
But it's important to know,especially when you're dealing
with web servers.
They'll wanna make sure thatyour certificate is a legitimate
and up-to-date certificate andif not, they're gonna want to
(21:10):
get you a new one.
So let me walk through aprocess of how this would happen
.
So you have a digitalcertificate that and Alice owns
a public key for encrypting andsigning messages.
Now the information that's inthis digital certificate has the
name and the public key ofAlice, the name and the
(21:31):
signature of the intermediate,ca, and the serial number and
expiration date of thecertificate itself.
Specifically, it talks aboutthe purpose of this certificate
for, whether it's for signingdocuments, whatever it might be,
and then the potential scopefor it.
The XO5 standard has variousversions and extensions that tie
into this as well.
So the digital certificate thatis tied to Alice can be
(21:52):
validated by checking thesignature of the intermediate CA
against the public key, whichis obtained, obviously, from the
root CA certificate.
The digital certificate thencan be revoked by the CA if her
private key, if Alice's privatekey, is potentially compromised
or if she violates the terms ofthe certificate itself, using it
for something it shouldn't be.
This digital certificate canalso be renewed by the
(22:16):
intermediate CA before itspecifically expires and I've
had to do this myself where youcan actually go out and get a
new digital certificate beforeit actually goes out.
Most of the time this is done,like I said, automatically it
will do this for you, but youcan actually manually go and do
this process as well.
Once this happens, this digitalcertificate is then pinned
(22:36):
directly to Alice, who it trusts, and the client does not have
the ability to do anything withit.
It validates the certificateevery time it communicates with
Alice and it verifies that iswho she specifically is.
Now let's kind of walk throughthe the life cycle of a digital
certificate.
So we have enrollment, so Aliceagain requests a certificate
from the intermediate CA toprovide her identity and her
(22:59):
public key.
So obviously we talked aboutintermediate CAs.
You have your root C and thenyou have your intermediate CAs
Most various companies.
There's lots of intermediateCAs out there.
You can actually get that listoff your computer.
You can understand who are allof the authorities that are tied
to your certificates on yourcomputer.
That can all be looked at,depending on what version you
(23:20):
have and where it's locatedwhether it's Windows, whether
it's Linux or whether it'sactually in a mic or a apple
type version.
Now the intermediate ca willverify alice's identity and her
public key and then issues acertificate to her.
A client who wants tocommunicate with alice will
validate her certificate bychecking the signature of the
(23:40):
intermediate ca and theexpiration of the overall
certificate.
Then if that becomes a problemand she has to revocate or
revoke to get the certificaterevoked, the intermediate CA
will then revoke her certificateif her private key is ever
compromised and they're aware ofthat, or if she obviously
violates the terms of service.
And then that's part of whatthey call a CRL, which is your
(24:01):
Certificate Revocation List.
There's also an online versionof this called the Online
Certificate Status Protocol,ocsp.
That's a server that's outthere that will look for these
certificates as well and then,once that occurs, the
intermediate CA will renewAlice's certificate before it
expires or, if it has beencompromised, they'll renew that
(24:21):
as well, depending upon whatoccurred and why it was actually
compromised.
So, again, these certificatesare an important factor, digital
certificates are, and you havevarious pieces of this as it
relates to how you're going tohandle the certificate for your
specific identity.
Last thing we're going to getinto is SMIME.
So SMIME is a standard forpublic key encryption that
(24:43):
provides security services fordigital messaging applications.
Now it originally starts off.
It's tied into PKI, which isyour public key infrastructure.
Now the basic security servicesthat are with S-MIME are
authentication, non-repudiationof the origin, message integrity
and then confidentiality.
Now S-MIME is a culmination ofwhat started off as MIME.
(25:05):
So we're talking MIME.
It's M-I-M-E, so Mike India,mike Echo.
Now MIME did not addresssecurity issues.
It was just basically developedfor messages.
But as time has gone on, thereneeded to be some level of
security added to this overallstandard.
So they created what they calla S-slash slash MIME, which adds
features to your emailmessaging, including the digital
(25:27):
signatures which we talkedabout encryption for message
privacy and then, obviously,hashing for message integrity
and non-repudiation.
So that's where the S MIMEcomes into play.
Now an example of an S MIME.
We'll kind of get put this intoaction again.
Is?
We got Alice and Bob.
Now Alice wants to send themessage, a secure message, to
Bob, who has her public key, andhe has this public key from a
(25:49):
certificate issued by a trustedCA right.
So Alice uses Bob's public keyto encrypt the message content
and generate what he, what she,what she calls.
What they call is a messagedigest we talked about earlier,
which hashes the message.
Alice then signs the messagedigest with her own private key,
creating a digital signaturethat proves her identity as the
(26:14):
sender and prevents anyone fromaltering the message.
Alice then takes and attachesher public key certificate and
Bob's public key certificate tothe email, along with the
encrypted message and thedigital signature.
So you got four things in placehere Alice's public key, bob's
public key, the message itselfthat's encrypted, and the
(26:34):
digital signature.
Alice will then send the emailto Bob using standard MIME
format, but with a secure MIMEheader indicating that the
security features have been used.
So that's the key piece of thisis that it's a MIME message,
mime header indicating that thesecurity features have been used
.
So that's the key piece of thisis that it's a MIME message,
mime format, but it's a slash Sslash MIME to show you that the
security features have been used.
(26:55):
Specifically, Bob receives thisemail and then verifies the
certificates with the CA,ensuring that they're valid and
then that they have been revoked.
And then Bob uses his ownprivate key, which is in
compromise, to decrypt themessage content and Alice's
public key to verify hersignature.
So you got Alice's public keyto verify the signature.
You got Bob's private key todecrypt the message because he
(27:18):
used his public key, and thenalso to verify the digital
signature and the message digestconfirming Alice's identity and
the message integrity.
Bob uses his own private key todecrypt the message and then
Alice's public key to verify thedigital signature and the
message digest.
So that verifies that Alice iswho she says she is.
(27:38):
Bob can read the message andreply to Alice using the same
procedure, going backwards or ifhe uses a different security
protocol, if he chooses.
The bottom line is again, we'llwalk this through one more time.
Alice wants to send a messageto Bob the secure message who
has a public key certificatethat's issued out there on the
internet by a trusted CA.
(27:59):
Alice uses Bob's public key, soshe takes his public key, she
encrypts the message content andgenerates a message digest Okay
.
So that's again.
That's the hash.
That's the hash of the overallmessage itself.
Alice signs the message digestthat she was just created with
her own private key.
So the private key she owns noone else has.
(28:20):
She then signs it with that,creating a digital signature
that proves she is who she saysshe is.
She then sends this, or sheattaches the public key
certificate okay, that Bob'spublic key to the email, along
with the encrypted message andthe digital signature that she
created.
She sends this to Bob throughan email using standard MIME
(28:43):
format with an S slash header,to Bob through an email using
standard MIME format with an Sslash header.
And then Bob receives the emailand verifies that the
certificate with the CA.
So her certificate is confirmedwith the CA, ensuring that
they're valid and it hasn't beenrevoked.
Bob then uses his own privatekey to decrypt the message.
He's got a private key, it'sbeen encrypted with his public
key.
It's now verifies the message.
(29:04):
So the message is unencrypted,but then he's able to utilize
Alice's public key, which is outon the internet, to verify her
digital signature and themessage digest are correct.
So then they're both equal.
So that hasn't had anythingthat's happened to the message
digest at all.
It's all there and then Bob canread the message and obviously
reply to her as he sees fit.
(29:25):
So that is the overall exampleof an S-MIME.
Speaker 1 (29:28):
Okay, that's all I have for you today.
I hope you all have a wonderfulday.
Speaker 2 (29:32):
Head on over to CISSP Cyber Training and catch out
what we got.
All these videos are there freefor you to gain access to.
They're on the blog.
You can go check them out.
Also, if you're interested, Ihave some paid products out
there as well for you.
To help you pass the CISSP thefirst time, I have a blueprint.
That's amazing.
Everybody that uses it passes.
They are doing a great job withthis.
If they follow what theblueprint offers, you will pass
(29:56):
the CISSP exam.
If you're interested in justgetting the free content, it's
there and available for you aswell.
All of that is there at CISSPCyber Training.
Go check it outcisspcybertrainingcom.
Check it out.
Let me know.
If you have any questions atall.
Feel free to respond to me inthe.
There's different places.
(30:17):
You can reply to me or just letme know what you need, but I'm
here for you at that CISSP CyberTraining.
Head on over there, check itout.
Also, you can get 30 or 60 freeCISSP questions.
Just go tofreecisspquestionscom and you
can get answers to those as well.
All right, have a wonderful dayand we will catch you on the
flip side, see ya.
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