def encrypt_CTR_(plain_text, key, IV): # check pass
"""
Counter Mode Encryption in AES, using increment-by-one method
* Attention(Very similar with OFB mode):
- CTR belongs to stream cipher mode, which can operate any size of plaintext and cipher,
so there is no need for padding.
- Whether in encryption or decryption in CTR mode, only AES_RAW encryption has been used.
:param plain_text: plaintext that needed to be encrypted --> bytes
:param key: AES key --> bytes
:param IV: fixed initial value/nonce(8 bytes) --> bytes
:return: cipher --> bytes
"""
if len(IV) != 8: # check the IV length
raise ValueError("Invalid IV!")
counter = 0
cipher = b''
for i in range(0, len(plain_text), 16):
v = IV + counter.to_bytes(8, 'big')
output = AES_RAW.new().encrypt(v, key)
if i + 16 > len(plain_text): # if the last block is incomplete
x = plain_text[i:]
else:
x = plain_text[i:i+16]
x = bytes([x[b] ^ output[b] for b in range(len(x))])
cipher += x
counter += 1 # increment by one
return cipher
def decrypt_CTR_(cipher, key, IV): # check pass
"""
Counter Mode Decryption in AES, using increment-by-one method
:param cipher: cipher that need to be decrypted --> bytes
:param key: AES key --> bytes
:param IV: fixed initial vector/nonce(8 bytes) --> bytes
:return: plaintext --> bytes
"""
if len(IV) != 8: # check the IV length
raise ValueError("Invalid IV!")
counter = 0
plain_text = b''
for i in range(0, len(cipher), 16):
v = IV + counter.to_bytes(8, 'big')
output = AES_RAW.new().encrypt(v, key)
if i + 16 > len(cipher): # if the last block is incomplete
x = cipher[i:]
else:
x = cipher[i:i+16]
x = bytes([x[b] ^ output[b] for b in range(len(x))])
plain_text += x
counter += 1 # increment by one
return plain_text
def encrypt_CFB_(plain_text, key, IV): # check pass, but not the same as Crypto Package, confused...
"""
Cipher Feedback Mode Encryption in AES
* Attention(Very similar with OFB mode):
- CFB belongs to stream cipher mode, which can operate any size of plaintext and cipher,
so there is no need for padding.
- Whether in encryption or decryption in CFB mode, only AES_RAW encryption has been used.
:param plain_text: plaintext that needed to be encrypted --> bytes
:param key: AES key --> bytes
:param IV: initial vector(16 bytes) --> bytes
:return: cipher --> bytes
"""
if len(IV) != 16: # check the IV length
raise ValueError("Invalid IV!")
cipher = b''
v = IV
for i in range(0, len(plain_text), 16): # check pass
output = AES_RAW.new().encrypt(v, key)
if i + 16 > len(plain_text): # if the last block is incomplete
x = plain_text[i:]
else:
x = plain_text[i:i+16]
v = bytes([x[b] ^ output[b] for b in range(len(x))])
cipher += v
return cipher
def encrypt_ECB_(plain_text, key, pad="PKCS#7"): # check pass
"""
Electronic Code Book Mode Encryption in AES
:param plain_text: plaintext that needed to be encrypted --> bytes
:param key: AES key --> bytes
:param pad: padding mode --> str
:return: cipher --> bytes
"""
plain_text = padding(plain_text, pad)
cipher = b''
for i in range(0, len(plain_text), 16):
cipher += AES_RAW.new().encrypt(plain_text[i:i+16], key)
return cipher
def decrypt_ECB_(cipher, key, pad="PKCS#7"): # check pass
"""
Electronic Code Book Mode Decryption in AES
:param cipher: cipher that needed to be decrypted --> bytes
:param key: AES key --> bytes
:param pad: padding mode --> str
:return: plaintext --> bytes
"""
if len(cipher) % 16: # check cipher length
raise ValueError("Invalid cipher length!")
plain_text = b''
for i in range(0, len(cipher), 16):
plain_text += AES_RAW.new().decrypt(cipher[i:i+16], key)
plain_text = unpadding(plain_text, pad)
return plain_text
def encrypt_CBC_(plain_text, key, IV, pad="PKCS#7"): # check pass
"""
Block Cipher Chaining Mode Encryption in AES
:param plain_text: plaintext that needed to be encrypted --> bytes
:param key: AES key --> bytes
:param IV: initial vector(16 bytes) --> bytes
:param pad: padding mode --> str
:return: cipher --> bytes
"""
if len(IV) != 16: # check the IV length
raise ValueError("Invalid IV!")
plain_text = padding(plain_text, pad)
cipher = b''
v = IV
for i in range(0, len(plain_text), 16):
x = bytes([plain_text[i+b] ^ v[b] for b in range(16)])
v = AES_RAW.new().encrypt(x, key)
cipher += v
return cipher
def decrypt_CFB_(cipher, key, IV): # check pass, but not the same as Crypto Package, confused...
"""
Cipher Feedback Mode Decryption in AES
:param cipher: cipher that needed to be decrypted --> bytes
:param key: AES key --> bytes
:param IV: initial vector(16 bytes) --> bytes
:return: plaintext --> bytes
"""
if len(IV) != 16: # check the IV length
raise ValueError("Invalid IV!")
plain_text = b''
v = IV
for i in range(0, len(cipher), 16):
output = AES_RAW.new().encrypt(v, key)
if i + 16 > len(cipher): # if the last block is incomplete
v = cipher[i:]
else:
v = cipher[i:i+16]
x = bytes([v[b] ^ output[b] for b in range(len(v))])
plain_text += x
return plain_text
def decrypt_OFB_(cipher, key, IV): # check pass
"""
Output Feedback Mode Decryption in AES
:param cipher: cipher that needed to be decrypted --> bytes
:param key: AES key --> bytes
:param IV: initial vector(16 bytes) --> bytes
:return: plaintext --> bytes
"""
if len(IV) != 16: # check the IV length
raise ValueError("Invalid IV!")
plain_text = b''
v = IV
for i in range(0, len(cipher), 16):
v = AES_RAW.new().encrypt(v, key)
if i + 16 > len(cipher): # if the last block is incomplete
x = cipher[i:]
else:
x = cipher[i:i+16]
x = bytes([x[b] ^ v[b] for b in range(len(x))])
plain_text += x
return plain_text
def decrypt_CBC_(cipher, key, IV, pad="PKCS#7"): # check pass
"""
Block Cipher ChainingMode Decryption in AES
:param cipher: cipher that needed to be decrypted --> bytes
:param key: AES key --> bytes
:param IV: initial vector(16 bytes) --> bytes
:param pad: padding mode --> str
:return: plaintext --> bytes
"""
if len(IV) != 16: # check the IV length
raise ValueError("Invalid IV!")
if len(cipher) % 16: # check cipher length
raise ValueError("Invalid cipher length!")
plain_text = b''
v = IV
for i in range(0, len(cipher), 16):
x = AES_RAW.new().decrypt(cipher[i:i+16], key)
plain_text += bytes([x[b] ^ v[b] for b in range(16)])
v = cipher[i:i+16]
plain_text = unpadding(plain_text, pad)
return plain_text