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in this topic I'd like to talk to you about corruption algorithms
they're going to cover a little bit about algorithms potential see
throughout our discussion of cryptography
going to learn more and more about them beyond this particular session
down Christian algorithms can be roughly divided into three categories:
symmetric algorithms asymmetric
and hashing now we haven't talked about hashing as a
yet we're going to talk about their little bit later so we're going to
shelved discussion on the hashing algorithms until another session
so for now let's focus on some metric in asymmetric you already know what's met
Ricky an asymmetric key cryptography are
Smet Ricky obviously users one key that encrypts and decrypts
an asymmetric uses a public and private key system
each of these methods have their different strengths weaknesses
n uses in cryptography algorithms
as we know can also be divided into streaming or block ciphers and they're
used in various applications as well
now some the algorithms that will talk about
are considered to be weak or broken or may just not be typically use because
they've been replaced by stronger algorithms
you still may need to know them for the exam so you'll know which ones you
shouldn't use
or if you're a hacker which ones you'll be best to target
since some cases algorithms are actually very strong
but the implementation method is weak
maybe it's a good out where them but it was not implemented in the system
properly
so hackers will target that as well
now let's talk about encryption algorithms from a general perspective
first
encryption strength is based upon really two key factors
strength the key and the strength to the algorithm
the key strength itself refers to the length and complexity
love the key obviously a single character password
isn't as strong as an eight character password so
length is a factor there in obviously having a password its
all lower case letters is not as strong as having a password its
upper case lower case special characters
in numbers and so forth so complexity comes into play there too
no algorithm strength relates to the mathematical complexity
oh the algorithm itself in there could be
elliptic curves it could be large prime numbers
it could be all kinds of different mathematical algorithms are formulas
the stronger the algorithm strongly encrypted in
stronger the key the stronger the encryption
now they're also weaknesses and strengthen the various methods and
algorithms are implemented
n we can discuss those a little bit as we go through the course
now I mention that algorithms are divided into symmetric
asymmetric in hashing we're gonna talk about hashing a little bit later
but you can also classify them as block or screaming
so let's talk about which ones are symmetric in which ones are asymmetric
in which ones are blocking which ones are streaming
now its easy to pick up the streaming
thats rc4 and to be perfectly honest
in most certification exams you take most cryptography discussions are really
going to mention rc4
as basically the only streaming algorithm you need to concern yourself
with
an RC four has one particular interesting news
it's used in way up and one on the way
reasons that way up in wireless communications is so
we can easily broken is not because our C four is a week algorithm
is because it was in implemented poorly so that makes web
easy to crack
rc4 along with the rest of these in the charts are symmetric algorithms now
obviously we have
old there's a Dell Inc Russian Standard which is very we can easily cracked the
we had tripled there's
which three times the
this a key size in round 7 crib shin but still easily broken
tripled as is not use widely much anymore except
in some cases to encrypt DVD eats and unfortunately it's easily broken
ADSs had an exceptional standard to the united states right now
and it comes in key size 128 bits 192 bits
and 256 bits now you notice in the third column
for type all these i'm talking about. blocks
except rc4 so it's worth mentioning
once again the rc4 you seen on the exam is the only streaming server you're
probably sick
there's also other ones like idea to fish Blowfish in RC five
now let's move on asymmetric algorithms and and there's only a few you really
need to worry about for the exam or really in real life
there's our essay which is a key size of 512 bits
Ennis again primarily used for encryption one thing about our essay
al gore them since we're talking asymmetric that's the main algorithm
issues in public and private key cryptography
so to develop an use a digital certificate
in a public and private key pair we use our essay
there's also ECC which is elliptical curve cryptography
and it has a variable key size an issue shrink wrap Shin
one thing about ECC in this is again you might see this on exam somewhere
is set it requires very low computing power
and this makes ideal for mobile devices like tablets in
smartphones so you might see a description a BCC tied to those types of
devices
and in fact its key length in the way it actually does its keys
is such that even a 128 bit key with ECC is equivalent to like a
3,000 some odd bit key for our essay so
even though it's a 128 bit key that still a very large key size for
normal encryption for ECC diffie-hellman el-gamal
are used to in key exchange is its their key exchange protocol so though el-gamal
can also be used for encryption
and digital signatures ok miles actually derivative loved if he hell min those
the four primary
algorithms you'll see tied to asymmetric in there all
blocked by the weather in much stream again the only streaming saffir you'll
see mention
is rc4 so that's just a quick down and dirty on the algorithms that you might
see on the exam
keep in mind that the CH exam was not going to test you extensively on
cryptography
it's more going to test you on which types a cryptography and how you might
break
that cryptography which ones are weak in with how you might break themselves
that's basically the extension going to see in cryptography on the CH exam