Hello OpenSSL users, I'm doing Diffie-Hellman key agreement between Java's built-in crypto and C++ using OpenSSL latest version 0.9.8g. The key agreement works and the generated shared secret bytes are the same on the Java and OpenSSL side.
The problem is when I try to use the bytes of the DH shared secret as the secret key to a symmetric cipher (say 3DES or Blowfish in CBC mode with PKCS5Padding) and encrypt some data from OpenSSL and send it to Java for decryption, I get a BadPaddingException. Now OpenSSL's default padding is the "standard/PKCS5" padding (verified by looking at the code) which is what I've specified on the Java side. So this might indicate a key and/or IV mismatch issue - I've set the IV to all zeroes to test. I believe I have specified for the Java side symmetric cipher to use the shared secret bytes directly as the key - I know 3DES needs odd parity (it uses the bytes by toggling the LSB of each byte to get odd parity) so I'm testing with Blowfish. But looking at the OpenSSL code for the "set key" functions for the various symmetric ciphers, it looks like we don't use the bytes directly, rather we are performing some operations on the bytes before setting it as the key? Is there any way I can get OpenSSL to directly use the bytes I provide (as the "key" param in EVP_EncryptInit) without modifying it so that I might avoid the BadPaddingException on the Java side? Or is there a different issue going on and my suspicion about the key being mismatched is incorrect? Thanks, Vishal ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager [EMAIL PROTECTED]
