Cryptographic security products, including Secure Socket Layer 3 for Java. [commercial]

A Sun JCE compliant Java cryptography library with CA functionality. [Free with Registration] (Entrust)

An open source cryptographic class library for the JCA/JCE architecture. [Open Source with registration]

Java implementation of the public key cryptosystem Hidden Field Equations (HFE). Also includes matrix and finite field operations. [Open source, GPL]

Provides a comprehensive set of Java-based crypto products. Java implementation TLS, SSLv3 and SSLv2(client side), S/MIMEv2. [Commercial]

A cryptographic service provider for Java. It includes implementations of the following cryptographic algorithms: RSA (PKCS1 and OAEP), Blowfish, RC2, DES, DESede (TripleDES), ARC Four (RC-4 compatible), Rijndael, HMac-SHA1, HMac-MD5. [Open source, Apache-style license]

A fully featured SSH2 library. By 3SP LTD. [Commercial]

Provides framework and implementations for encryption, key generation and key agreement, and Message Authentication Code (MAC) algorithms.

Clean-room JCE framework implementation with S/MIME, Kerberos 5, and SSL/TLS libraries.

Provides the functionality of a cryptographic cipher for encryption and decryption. It can encrypt or decrypt byte array, stream or object base on DES, TripleDES, AES(Rijndael) algorithms without JCE framework. [Commercial]

Reimplemented the Java SDSI (Simple Distributed Security Infrastructure) API. [Open source, MIT License]

Provides open source implentations of the Java Cryptography Extension 1.2.1, and a lightweight Java Cryptography API for the J2ME, and the JDK. [Open Source]

Formerly Cryptonite, a pure java package for strong cryptography. It supplies RSA (usable outside of North America), DES, Triple-DES implementation as well as other utility classes. [Open Source, GPL/Commercial]

Libraries used internally by Netscape and iPlanet products that do crypto in Java. [Mozilla]

Public key signature system QuartzLight [Open Source, GPL].

Toolkits for SSL, general cryptography, and PKI. [Commercial]

The source code of the 128-bit PC1 cipher algorithm in Java.

Allegedly "one of the fastest and most efficient cryptographic algorithms in existence". [Open Source]