classicrack

[wip 🛠️] A Python library for implementing and cracking classical ciphers (Atbash, Caesar, ROT13, etc.)

Supported Ciphers

• Affine
• Atbash
• Caesar
• ROT13

Documentation

Full Docs: https://classicrack.readthedocs.io/en/latest/

Installation

pip install -r requirements.txt

Cryptanalysis

For cracking, cipher implementations have a crack() method. Implementations of some ciphers, such as ROT-13 and Atbash do not have it, since the decode() method already performs the same task.

So far, classicrack can only perform cryptanalysis on ciphers with keyspace weaknesses (e.g. Affine, Caesar). Implementations for other ciphers such as Vigenere might be added soon.

Ciphers

Affine

Example

from classicrack.ciphers import Affine
af = Affine()
# encode (plaintext, a, b)
af.encode('cheemsburger', 5, 8)
# decode (ciphertext, a, b)
af.decode('srccqunepmcp', 5, 8)
# crack (ciphertext)
af.crack('srccqunepmcp')

encode (pt, a, b): encrypts the input plaintext using Affine

• pt: the input plaintext
• a: a slope value, which must be a positive integer coprime with 26
• b: an intercept value, which can take any positive integer

decode (ct, a, b): decrypts an input ciphertext using Affine

• ct: the input ciphertext
• a: a slope value, which must be a positive integer coprime with 26
• b: an intercept value, which can take any positive integer

crack (ct): cracks an input Affine ciphertext

• ct: the input ciphertext

Atbash

Example

from classicrack.ciphers import Atbash
ab = Atbash()
# encode
ab.encode('zebras')
# decode
ab.decode('avyizh')

encode (pt): encrypts the input plaintext using Atbash

• pt: the input plaintext

decode (ct): decrypts a ciphertext using Atbash

• ct: the input ciphertext

Caesar

Example

from classicrack.ciphers import Caesar
cs = Caesar()
# encode
cs.encode('cheemsburger', 13)
# decode
cs.decode('purrzfohetre', 13)
# crack
cs.crack('purrzfohetre')

encode (pt, shift): encrypts the input plaintext with Caesar’s Cipher

• pt: the input plaintext
• shift: a shift value, which can be any positive integer

decode (ct, a, b): decrypts a ciphertext encrypted with Caesar’s Cipher

• ct: the input ciphertext
• shift: a shift value, which can be any positive integer

crack (ct): cracks an input Caesar ciphertext

• ct: the input ciphertext

ROT13

Example

from classicrack.ciphers import ROT13
rot = ROT13()
# encode
rot.encode('cheemsburger')
# decode
rot.decode('purrzfohetre')

encode (pt): encrypts the input plaintext with ROT-13

• pt: the input plaintext

decode (ct): decrypts a ciphertext encrypted with ROT-13

• ct: the input ciphertext

License

MIT License