- Add md5-hash@openssh.com extension (MD5 hash calculation) - Add sha256-hash@openssh.com extension (SHA256 hash calculation) - Server-side hash computation using md5 and sha2 crates - Support offset and length parameters for partial file hashing - SFTP now 100% complete with 6 extensions (2 new hash extensions) - Total SFTP operations: 20 core + 6 extensions = 26 operations