cipher_implementations_rust

Project contains the rust implementation's of all the cryptography methods I learn. List of ciphers I will be implementing are:

Hill Cipher
Caesar Cipher : A Caesar Cipher is one of the most simple and easily cracked encryption methods. It is a Substitution Cipher that involves replacing each letter of the secret message with a different letter of the alphabet which is a fixed number of positions further in the alphabet.

Example : each letter in the plaintext message has been shifted 3 letters down in the alphabet.

Plaintext: This is a secret message

Ciphertext: wklv lv d vhfuhw phvvdjh

Keyword Cipher: Keyword cipher is a form of monoalphabetic substitution. A keyword is used as the key, and it determines the letter matchings of the cipher alphabet to the plain alphabet. Repeats of letters in the word are removed, then the cipher alphabet is generated with the keyword matching to A, B, C, etc. until the keyword is used up, whereupon the rest of the ciphertext letters are used in alphabetical order, excluding those already used in the key.

Implementation

To create a substitution alphabet from a keyword, you first write down the alphabet. Below this you write down the keyword (omitting duplicate letters) followed by the remaining unused letters of the alphabet
```
  ABCDEFGHIJKLMNOPQRSTUVWXYZ
  KEYWORDABCFGHIJLMNPQSTUVXZ
```
To encipher a plaintext message, you convert all letters from the top row to their corresponding letter on the bottom row (A to K, B to E, etc).

Ex: plaintext = "Hello world" keyword = "secret"

encrypted = "dtiil wloir"
Affine Cipher The affine cipher is a type of monoalphabetic substitution cipher,which has 2 keys. Let us consider Key 1(a) and key 2 (b) and plaintext(x) when encrypting we use a*X+b mod 26 to encrypt the message. While we can use a(inverse)*(y-b) mod 26 to decrypt the encrypted message

Ex: Key = Hello, World!, Key 1 = 5, key 2 = 8

encryption = Rclla, Oaplx!
Vigener Cipher (16th century, Rome) It is an cipher that was being developed by an Roman by named Vigener, In this cipher we have a key(K) and a message (M) when encrypting we replicate key length to the length of the message and add then together with mod 26. Similarly, you do the same with the decryption only in this case you substract with mod 26

Ex: Key = CRYPTO Message = WHATANICEDAYTODAY Implementation
```
   key       =  CRYPTOCRYPTOCRYPT
   message   =  WHATANICEDAYTODAY 
   -------------------------------- + mod 26
   encrypt   =  ZZZJUCLUDTUNWGCQS
   -------------------------------- 
   encrypt   =  ZZZJUCLUDTUNWGCQS
   key       =  CRYPTOCRYPTOCRYPT
   -------------------------------- - mod 26
   message   =  WHATANICEDAYTODAY
   
```
Roter machines cipher (1870-1943) It consists of a key with which a letter mapping was done, Initially the roter was mapped with the key but with each keystroke, the key map also routed making it slightly difficult, In cases when an user types c for three times the encryption will yeld 3 different characters thus making it slightly harder to crack, These improvised and then they become multi-roter the infamous Enigma is an example for Router machine cipher.
One time pad cipher : The one-time pad is a long sequence of random letters. These letters are combined with the plaintext message to produce the ciphertext. To decipher the message, a person must have a copy of the one-time pad to reverse the process. A one-time pad should be used only once (hence the name) and then destroyed. This is the first and only encryption algorithm that has been proven to be unbreakable.

Implementation

Given any plaintext we have generate one time key randomly and that key is same as the length of plaintext, The plaintext is encrypted using the one time pad and the same one time pad is shared to use it to decode the information.

Example:
plaintext    : SECRETMESSAGE
one-time pad : CIJTHUUHMLFRU
ciphertext   : UMLKLNGLEDFXY

Atbash Cipher: The Atbash cipher is a very specific case of a substitution cipher where the letters of the alphabet are reversed. In otherwords, all As are replaced with Zs, all Bs are replaced with Ys, and so on. Because reversing the alphabet twice will get you actual alphabet, you can encipher and decipher a message using the exact same algorithm.

Example

Plaintext: This is a secret message

Ciphertext: Gsrh rh z hvxivg nvhhztv

Please feel free to open an issue if you would like to implement a new cipher and can submit a PR.

Ekaanth/cipher_implementation_rust

cipher_implementations_rust