A Tour of CommonCrypto
CommonCrypto is a convenient library provided with Mac OS X and iOS that provides a range of cryptographic primitives. It provides cryptographic hashes, message-authentication codes and key-derivation functions based on those hashes, and symmetric encryption. It's not a fully-featured cryptography library like OpenSSL, as it's missing more complex features such as public key cryptography and common protocols like TLS. However, if your needs fit within its capabilities, CommonCrypto is easy to use and requires no third-party code.