DE25851: Made Encryptor#encrypt thread safe and improved performance … #107
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irinaepshteyn
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Done reviewing. Please review my comments.
| // Rigorous checks to make sure we've absolutely got the correct instance (with correct alg/key/iv/...) | ||
| if (cachedCipher != null && cachedCipher.isCipherValid(iv, cipherMode, this.secretKeySpec)) { | ||
| return cachedCipher.cipher; | ||
| } |
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Caching cipher seems like unnecessary overhead. isCipherValid does comparison on cipherMode (ENCRYPT_MODE or DECRYPT_MODE) and on IV. If the same thread is used continuously to encrypt (or decrypt), the cached cipher will be thrown away each time as new IV is generated for every encryption/decryption operation. If same thread is used to encrypt and then decrypt, cached cypher will be thrown away as mode is different. I can't come up with the use case when cached cypher is actually used.
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Apart from maybe allowing flexibility to change the algorithm and not having to change this code, I agree with you. For now, I've changed it to just cache the Cipher instance thread-locally (agnostic of Cipher#init).
| CIPHER_THREAD_LOCAL.set(new CachedCipher(cipherMode, this.secretKeySpec, cipher)); | ||
| return cipher; | ||
| } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidAlgorithmParameterException | ||
| | InvalidKeyException e) { |
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It's better to catch a Throwable here and wrap anything that could go wrong with CipherInitializationFailureException
| throw new SymmetricKeyValidationException("Encryption key must be string of length " + KEY_LENGTH_IN_BYTES); | ||
| } | ||
| this.encryptionKey = encryptionKey; | ||
| this.secretKeySpec = new SecretKeySpec(encryptionKey.getBytes(), ALGO); |
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We could unload key length validation to SecretKeySpec(byte[] key, int offset, int len, String algorithm) constructor. It throws IllegalArgumentException if algorithm is null or key is null, empty, or too short, i.e. key.length-offset<len.
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Agreed. In the case that the key is longer than 16 bytes, the first 16 will be used (since the offset is 0)
…by using thread local instances of Cipher Signed-off-by: Anurag <[email protected]>
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Incorporated PR feedback and squashed changes
…by using thread local instances of Cipher
Signed-off-by: Anurag [email protected]