BouncyCastle
Try to use BC Crypto APIs to implement the crypto core function in my system. The point is how to implement ECDSA in mobile device. The speed is a more complicated issue. Generating Key for ECDSA should be solved in this week.
http://www.bouncycastle.org/ contribute somethings to you:
The Bouncy Castle Crypto APIs for Java consist of the following:
A lightweight cryptography API for Java and C#.
A provider for the Java Cryptography Extension and the Java Cryptography Architecture.
A clean room implementation of the JCE 1.2.1.
A library for reading and writing encoded ASN.1 objects.
A light weight client-side TLS API.
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/RFC 3852).
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 1.4-1.6 and the Sun JCE.
