Botan is a C++ library of cryptographic algorithms, including AES, DES, SHA-1, RSA, DSA, Diffie-Hellman, and many others. It also supports X.509 certificates and CRLs, and PKCS #10 certificate requests, and has a high level filter/pipe message processing system. The library is easily portable to most systems and compilers, and includes a substantial tutorial and API reference. This is the current 2.19.x release that reaches end-of-life at the end of 2024.