[Music]
hello everyone this is mr. random
generator in this video we will be
looking at top 5 ciphers throughout the
history starting off with the first one
Caesar cipher it is probably the most
known cipher out there and I guess many
of you heard it before it involves your
regular alphabets and the corresponding
two random letter sets when you want to
encrypt a message all you have to do is
replace each letter on the message
with the corresponding one on the cipher
by today's standards it is obviously
very easy to break however we know that
When Caesar was alive it was used
effectively moving on with the second
cipher the vigenère square this can be
thought as an advanced version of caesar
cipher it involves a table called
tabular vector to encrypt a message you
start off by creating a random key a
same length as your message then pick
letter from your message and find the
corresponding row after that click
letter from your key and find the
corresponding column the overlapping
letter is your encrypted letter it's
rate this process until you reach the
end of your message then you should have
an encrypted version of it to decrypt a
message all you have to do is iterate
over your key on the row of the square
then find corresponding letter in the
cipher-text the column letter should be
the letter on the original message now
we can look up other side which is the
famous enigma cipher it was developed by
an German engineer named Arthur Scherbius
it involves a keyboard light called
rotary disks and the flat board although
it is pretty complicated
electromechanical system it works in a
following way
first you put your numbered or lettered
rotors in certain order according to the
specifications you had then you
configure your blackboard according to
those specifications as well
after that you can encrypt decrypt
messages by typing on the keyboard the
result for each letter will show up on
the last whiteboard even if you type
same little multiple times the outcome
will be different and that is the beauty
of any
because you essentially alter the
electrical parts in every single
iteration obviously this is always
simplified explanation but you get the
idea and the cool part about enigma is
its effectiveness which is proven in the
Second World War until it is cracked by
the genius names Alan Turing which we
can say that he is the founding father
of the modern computer science from that
reason I have highly amazed and
interested in the Enigma machine even so
that I have created my own simplified
version using stm32 chip which you can
find up here anyway as for our final
encryption let's look at AES which
stands for advanced encryption standard
it is essentially based on Rijndael's
Cipher and it is the encryption
standard that is widely used today on
very high level it works in a following
way
initially we have to point out few
values first we got fixed inputs block
with a size of 128 bits then we got
multiple key blocks with varying sizes
of 128 192 and 256 bits first we start
with separating our text to 4x4 blocks
second we drive multiple keys from our
initial key according to the Rijndael's key
schedule this process is called key
expansion then we combine our initial
key with our block that contains the
message fragments by an XOR Cipher this
step is called adding the round key
after that things get bit operational we
first substitute bytes from a lookup
table then we shift Rows mix columns
and start to add our drive round keys we
repeat those operations multiple times
according to the key that we have chosen
initially if we have take hundred and
twenty eight bits version we repeated
nine times 192 bit version 11 times and
256 bits version
13 times the AES encryption is obviously
a very detailed topic to explain in a
short video so I will provide some
useful links in the description so you
understand the concepts in detail
like I hope you find this video helpful
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