Keyczar is an open source cryptographic toolkit designed to make it easier and safer for developers to use cryptography in their applications. Keyczar supports authentication and encryption with both symmetric and asymmetric keys. Some features of Keyczar include:

• A simple API
• Key rotation and versioning
• Safe default algorithms, modes, and key lengths
• Automated generation of initialization vectors and ciphertext signatures
• Java, Python, and C++ implementations
• International support in Java

Keyczar was originally developed by members of the Google Security Team and is released under an Apache 2.0 license.

• Discussion Group
• Design Document (PDF)

Cryptography is easy to get wrong. Developers can choose improper cipher modes, use obsolete algorithms, compose primitives in an unsafe manner, or fail to anticipate the need for key rotation. Keyczar abstracts some of these details by choosing safe defaults, automatically tagging outputs with key version information, and providing a simple programming interface.

Keyczar is designed to be open, extensible, and cross-platform compatible. It is not intended to replace existing cryptographic libraries like OpenSSL, PyCrypto, or the Java JCE, and in fact is built on these libraries.

Suppose an application needs to encrypt a URL parameter value with a symmetric key. Normally, a developer would need to decide which algorithm to use, the key length to use, the mode of operation, how to handle initialization vectors, how to rotate keys, and how to sign ciphertexts. Keyczar simplifies these choices. Using an existing keyset, a Java developer would need to call the following:

Crypter crypter = new Crypter("/path/to/your/keys");
String ciphertext = crypter.encrypt("Secret message");

Similarly a Python developer would call the following:

crypter = Crypter.Read("/path/to/your/keys");
ciphertext = crypter.Encrypt("Secret message");

Interested in getting involved? We encourage open source developers to contribute to the Keyczar project. Please join us on the Keyczar project and subscribe to the Keyczar discussion group.