40 lines
1.1 KiB
Plaintext
40 lines
1.1 KiB
Plaintext
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== How to fix it in BouncyCastle
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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,java,diff-id=201,diff-type=noncompliant]
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----
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public void encrypt(byte[] key, byte[] ptxt) {
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byte[] nonce = "7cVgr5cbdCZV".getBytes(StandardCharsets.UTF_8);
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BlockCipher engine = new AESEngine();
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AEADParameters params = new AEADParameters(new KeyParameter(key), 128, nonce);
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CCMBlockCipher cipher = new CCMBlockCipher(engine);
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cipher.init(true, params); // Noncompliant
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}
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----
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==== Compliant solution
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[source,java,diff-id=201,diff-type=compliant]
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----
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public void encrypt(byte[] key, byte[] ptxt) {
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SecureRandom random = new SecureRandom();
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byte[] nonce = new byte[12];
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random.nextBytes(nonce);
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BlockCipher engine = new AESEngine();
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AEADParameters params = new AEADParameters(new KeyParameter(key), 128, nonce);
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CCMBlockCipher cipher = new CCMBlockCipher(engine);
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cipher.init(true, params);
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}
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----
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include::../../common/how-does-this-work.adoc[]
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