The Bouncy Castle Crypto APIs consist of the following:

. A lightweight cryptography API in Java.
. A provider for the JCE and JCA.
. A clean room implementation of the JCE 1.2.1.
. A library for reading and writing encoded ASN.1 objects.
. Generators for Version 1 and Version 3 X.509 certificates, Version 2 CRLs,
  and PKCS12 files.
. Generators for Version 2 X.509 attribute certificates.
. Generators/Processors for S/MIME and CMS (PKCS7).
. Generators/Processors for OCSP (RFC 2560).
. Generators/Processors for TSP (RFC 3161).
. Generators/Processors for OpenPGP (RFC 2440).
. A signed jar version suitable for JDK 1.4/1.5 and the Sun JCE.

It's distributed under a modified X license.

WWW: http://www.bouncycastle.org/