FlexiProvider
- An open source cryptographic class library for the JCA/JCE architecture. [Open Source with registration]
- http://flexiprovider.cdc.informatik.tu-darmstadt.de/

FlexiCrypt
- Crypto toolkit based on FlexiProvider.
- http://developer.gauner.org/flexicrypt/

J2SSH Maverick
- A fully featured SSH2 library. By 3SP LTD. [Commercial]
- http://3sp.com/showMaverick.do

RSA BSAFE
- Toolkits for SSL, general cryptography, and PKI. [Commercial]
- http://www.rsasecurity.com/node.asp?id=1202

JSDSI
- Reimplemented the Java SDSI (Simple Distributed Security Infrastructure) API. [Open source, MIT License]
- http://jsdsi.sourceforge.net/

IAIK Java Crypto Products
- Provides a comprehensive set of Java-based crypto products. Java implementation TLS, SSLv3 and SSLv2(client side), S/MIMEv2. [Commercial]
- http://jce.iaik.tugraz.at/

QuartzLight in Java
- Public key signature system QuartzLight [Open Source, GPL].
- http://www.christopher-wolf.de/ql/

Hidden Field Equations (HFE) in Java
- Java implementation of the public key cryptosystem Hidden Field Equations (HFE). Also includes matrix and finite field operations. [Open source, GPL]
- http://www.christopher-wolf.de/hfe/

Network Security Services for Java (JSS)
- Libraries used internally by Netscape and iPlanet products that do crypto in Java. [Mozilla]
- http://www.mozilla.org/projects/security/pki/jss/

Java Cryptography Extension (JCE)
- Provides framework and implementations for encryption, key generation and key agreement, and Message Authentication Code (MAC) algorithms.
- http://java.sun.com/products/jce/

Baltimore Technologies
- Cryptographic security products, including Secure Socket Layer 3 for Java. [commercial]
- http://www.baltimore.com/

Legion of The Bouncy Castle
- 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]
- http://www.bouncycastle.org/