Sandra 0.0.18

AES Stream Cipher with CFB and OpenPGP Modes

Sandra

Sandra implements CFB and OpenPGP-CFB built on top of pycryptodome.

Usage

Loading Data

Sandra.load_data(

    path # str -> path to data to be loaded

)

Writing Data

Sandra.write_data(

   file_names, # name of files to be written

   file_data, # data to be written, must be the same length as file_names

   path='.' # path to write data to

)

Examples

RSA File Encryption

import Sandra

file_names, file_data = Sandra.load_data('./taylor_txt/taylor_swift_1KB.txt') 

enc_dec_rsa = Sandra.RSA(2048, Sandra.RSA_ENGINE_DOME)

ciphertext = enc_dec_rsa.encrypt(file_data[0])

print(len(ciphertext))

plaintext = enc_dec_rsa.decrypt(ciphertext)

print(plaintext == file_data[0])

Sandra.write_data(

    file_names, # name of the file to be written

    [plaintext], # data to be written, must be the same length as file_names

    path='./taylor_txt_ed' # path to write data to

)

AES CFB Mode Sample(NIST) Encryption

import Sandra

#Test Case from http://csrc.nist.gov/groups/STM/cavp/block-ciphers.html#aes

data = bytes.fromhex('fffffe00000000000000000000000000')

iv   = bytes.fromhex('fffffe00000000000000000000000000')

key  = bytes.fromhex('00000000000000000000000000000000')



enc_dec_sandra = Sandra.AES(key, Sandra.MODE_CFB, iv, segment_size=16)

ciphertext = enc_dec_sandra.encrypt(data)

plaintext = enc_dec_sandra.decrypt(ciphertext)

AES CFB Mode File Encryption

import Sandra

iv   = bytes.fromhex('fffffe00000000000000000000000000')

key  = bytes.fromhex('00000000000000000000000000000000')

file_names, file_data = Sandra.load_data('./taylor_txt/taylor_swift_1KB.txt') 

enc_dec_cfb = Sandra.AES(key, Sandra.MODE_CFB, iv, segment_size=16)

ciphertext = enc_dec_cfb.encrypt(file_data[0])

print(len(ciphertext))

plaintext = enc_dec_cfb.decrypt(ciphertext)

print(plaintext == file_data[0])

Sandra.write_data(

    file_names, # name of the file to be written

    [plaintext], # data to be written, must be same length as file_names

    path='./taylor_txt_ed' # path to write data to

)

AES OpenPGP-CFB Mode File Encryption

In This mode, the first 18 bytes of cipher text contain the encrypted IV

Padding here is unnecessary as this mode is a stream cipher

import Sandra

iv   = bytes.fromhex('fffffe00000000000000000000000000')

key  = bytes.fromhex('00000000000000000000000000000000')

file_names, file_data = Sandra.load_data('./taylor_txt/taylor_swift_1KB.txt')

print(len(file_data[0]))

file_data_padded = Sandra.pad(file_data, Sandra.AES_BLOCK_SIZE) 

print(len(file_data_padded[0]))

enc_dec_pgp = Sandra.AES(key, Sandra.MODE_OPENPGP, iv)

ciphertext = enc_dec_pgp.encrypt(file_data_padded[0])

eiv, ciphertext = ciphertext[:18], ciphertext[18:]

print(len(ciphertext))

plaintext = enc_dec_pgp.decrypt(ciphertext)

print(len(plaintext))

plaintext = Sandra.unpad(plaintext,Sandra.AES_BLOCK_SIZE)

print(len(plaintext))

print(plaintext == file_data[0])

Sandra.write_data(

    file_names, # name of the file to be written

    [plaintext], # data to be written, must be the same length as file_names

    path='./taylor_txt_ed' # path to write data to

)

Performance

To obtain a table like this one, run

import Sandra

file_names, file_data = Sandra.load_data('path/to/data')

stats = Sandra.performance_test(

    file_names, 

    file_data, 

    rsa_key_size=256,

    rsa_engine=Sandra.RSA_ENGINE_RAW,

    segment_size=64,  

    verbose=True)



stats = Sandra.performance_test(

    file_names, 

    file_data, 

    rsa_key_size=256,

    rsa_engine=Sandra.RSA_ENGINE_RAW,

    segment_size=16,  

    verbose=True)