35 lines
833 B
Plaintext
35 lines
833 B
Plaintext
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== How to fix it in pyca
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=== Code examples
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The example uses a hardcoded IV as a nonce, which causes AES-CCM to be insecure. To fix it, a nonce is randomly generated instead.
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==== Noncompliant code example
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[source,python,diff-id=201,diff-type=noncompliant]
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----
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from cryptography.hazmat.primitives.ciphers.aead import AESGCM
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def encrypt(key, plaintext):
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nonce = '7cVgr5cbdCZV'.encode('utf-8')
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cipher = AESGCM(key)
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cipher.encrypt(nonce, plaintext, None) # Noncompliant
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----
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==== Compliant solution
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[source,python,diff-id=201,diff-type=compliant]
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----
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from os import urandom
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from cryptography.hazmat.primitives.ciphers.aead import AESGCM
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def encrypt(key, plaintext):
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nonce = urandom(12)
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cipher = AESGCM(key)
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cipher.encrypt(nonce, plaintext, None)
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----
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include::../../common/how-does-this-work.adoc[]
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