For full, incremental, compressed and encrypted backups or archives
C++ cryptographic library (modern hash functions, ciphers, KDFs)
Powerful webdav client and sync tools with client-side AES encryption
antigift is simple cross-platform, files & folders encryption tool
52 Hash Functions In One Program, plus each with HMAC or KMAC
xxteac - XXTEA Encrypter/Decrypter