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javajavascriptalgorithmencryptionblowfish

Matching BlowfishJ Java implementation to dren blowfish javascript implementation; encryption values after 8-bytes are different

I'm having some issues with correlating the BlowsfishJ Java implementation (BlowfishJ Javadoc) to the dren Blowfish JavaScript implementation (dren Blowfish page).

On the Java side, I'm using Blowfish CBC, with a zero IV and the key is somekey. The plaintext is WillThisEQ.

On the JavaScript side, I PRESUME dren's implementation is using CBC and a zero IV, as well. The key is somekey and the plaintext is WillThisEQ, as well.

Here's the JavaScript code:

var bf = new Blowfish('some key');
var ciphertext = bf.encrypt('WillThisEQ');
var plaintext = bf.decrypt(ciphertext);

For the ciphertext, The first 8-bytes match for both implementations (WillThis). However, any subsequent bytes do NOT match (EQ000000). The IV is factored into the first block (Block Cipher Modes Wikipedia page). So, I don't think that's the problem.

How can I these two implementations to match?

Thank you very much for any help.

Solution

  • Your answer is at the very top of the dren BlowFish page you linked to:

    You need to impliment your own cipher-block chaining if you want to encrypt anything longer than 8 bytes.

    So no, it's not doing CBC. You could try the ECB version of BlowfishJ, but the security is much worse.