def ofb_encrypt(data, iv, key, type, thr=0):
encrypted = []
encrypted += data[:thr]
iv = iv
for ch in data[thr:]:
if type == 'caesar':
encr_ch = caesar.encrypt(iv, key)
elif type == 'vigenere':
encr_ch = vig.encrypt_chunk(iv, key)
elif type == 'affine':
encr_ch = aff.encrypt(iv, key['a'], key['b'])
iv = encr_ch
encr_ch = encr_ch ^ ch
encrypted.append(encr_ch)
return encrypted
def ofb_decrypt(cipher_data, iv, key, type, thr=0):
decrypted = []
decrypted += cipher_data[:thr]
iv = iv
for i in range(thr, len(cipher_data)):
if type == 'caesar':
decr_ch = caesar.encrypt(iv, key)
elif type == 'vigenere':
decr_ch = vig.encrypt_chunk(iv, key[i % len(key)])
elif type == 'affine':
decr_ch = aff.encrypt(iv, key['a'], key['b'])
iv = decr_ch
decr_ch = cipher_data[i] ^ decr_ch
decrypted.append(decr_ch)
return decrypted
def cbc_encrypt(data, iv, key, type, thr=0):
encrypted = []
iv = iv
encrypted += data[:thr]
for ch in data[thr:]:
xored = ch ^ iv
if type == 'caesar':
encr_ch = caesar.encrypt(xored, key)
elif type == 'vigenere':
encr_ch = vig.encrypt([xored], key)
elif type == 'affine':
encr_ch = aff.encrypt(xored, key['a'], key['b'])
iv = encr_ch
encrypted.append(encr_ch)
return encrypted