Compute cryptographic digests and HMACs deterministically: MD5, SHA-1, SHA-256, SHA-384, SHA-512, output as hex, base64,

Compute cryptographic digests and HMACs deterministically: MD5, SHA-1, SHA-256, SHA-384, SHA-512, output as hex, base64, or base64url. Add a "key" for HMAC. Built for checksums, content addressing, and signature verification. Inputs are hashed and discarded. POST a JSON body like: {"text":"hello world","algorithm":"sha256","encoding":"hex"}