include::../description.adoc[]

== Noncompliant Code Example

https://pycryptodome.readthedocs.io[pycryptodomex] library:

----
from Cryptodome.Cipher import AES, PKCS1_OAEP,  PKCS1_v1_5
from Cryptodome.Random import get_random_bytes
from Cryptodome.PublicKey import RSA

# Example for a symmetric cipher: AES
AES.new(key, AES.MODE_ECB)  # Noncompliant
AES.new(key, AES.MODE_CBC)  # Noncompliant

# Example for a asymmetric cipher: RSA
cipher = PKCS1_v1_5.new(key) # Noncompliant
----

https://cryptography.io/en/latest/[pyca] library:

----
import os
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric import rsa, padding
from cryptography.hazmat.primitives import hashes

# Example for a symmetric cipher: AES
aes = Cipher(algorithms.AES(key), modes.CBC(iv), backend=default_backend())  # Noncompliant
aes = Cipher(algorithms.AES(key), modes.ECB(), backend=default_backend())  # Noncompliant

# Example for a asymmetric cipher: RSA
ciphertext = public_key.encrypt(
  message,
  padding.PKCS1v15() # Noncompliant
)

plaintext = private_key.decrypt(
  ciphertext,
  padding.PKCS1v15() # Noncompliant
)
----

https://pypi.org/project/pyDes/[pydes] library:

----
# For DES cipher
des = pyDes.des('ChangeIt') # Noncompliant
des = pyDes.des('ChangeIt', pyDes.CBC, "\0\0\0\0\0\0\0\0", pad=None, padmode=pyDes.PAD_PKCS5) # Noncompliant
des = pyDes.des('ChangeIt', pyDes.ECB, "\0\0\0\0\0\0\0\0", pad=None, padmode=pyDes.PAD_PKCS5) # Noncompliant
----

https://pycrypto.readthedocs.io/en/latest/[pycrypto] library is not maintained and therefore should not be used:

----
# https://pycrypto.readthedocs.io/en/latest/
from Crypto.Cipher import *
from Crypto.Random import get_random_bytes
from Crypto.Util import Counter
from Crypto.PublicKey import RSA

# Example for a symmetric cipher: AES
AES.new(key, AES.MODE_ECB)  # Noncompliant
AES.new(key, AES.MODE_CBC, IV=iv)  # Noncompliant

# Example for a asymmetric cipher: RSA
cipher = PKCS1_v1_5.new(key) # Noncompliant
----

== Compliant Solution

https://pycryptodome.readthedocs.io[pycryptodomex] library:

----
from Cryptodome.Cipher import AES
from Cryptodome.Random import get_random_bytes
from Cryptodome.PublicKey import RSA

# AES is the recommended symmetric cipher with GCM mode
AES.new(key, AES.MODE_GCM)  # Compliant

# RSA is the recommended asymmetric cipher with OAEP padding
cipher = PKCS1_OAEP.new(key) # Compliant
----

https://cryptography.io/en/latest/[pyca] library:

----
import os
from cryptography.hazmat.primitives.ciphers import Cipher, algorithms, modes
from cryptography.hazmat.backends import default_backend
from cryptography.hazmat.primitives.asymmetric import rsa, padding
from cryptography.hazmat.primitives import hashes

# AES is the recommended symmetric cipher with GCM mode
aes = Cipher(algorithms.AES(key), modes.GCM(iv), backend=default_backend())  # Compliant

# RSA is the recommended asymmetric cipher with OAEP padding
ciphertext = public_key.encrypt(
  message,
  padding.OAEP( # Compliant
    mgf=padding.MGF1(algorithm=hashes.SHA256()),
    algorithm=hashes.SHA256(),
    label=None
  )
)

plaintext = private_key.decrypt(
  ciphertext,
  padding.OAEP( # Compliant
    mgf=padding.MGF1(algorithm=hashes.SHA256()),
    algorithm=hashes.SHA256(),
    label=None
  )
)
----

include::../see.adoc[]

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== Comments And Links
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include::../comments-and-links.adoc[]
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