​XySSL is an open-source cryptographic library for embedded systems. It provides standard crypto block: AES, SHA-1, X.509, etc. as well as higher lever protocols: SSL v3 and TLS v1. XySSL has been ported on a number of architectures, including ARM, PowerPC, MIPS, and Motorola 68000. Its already small memory footprint can be easily reduced to 50k for a basic SSL client or server, by modifying a single .h configuration file. XySSL is currently used in several open-source (GPL) and closed-source projects, such as Adobe's flash player.

Inzwischen wird XySSL nicht mehr weiter entwickelt. Der Nachfolger heißt ​PolarSSL.