DeriveECDHES derives a shared encryption key using ECDH/ConcatKDF as described in JWE/JWA.

KeyUnwrap implements NIST key unwrapping; it unwraps a content encryption key (cek) with the given block cipher.

KeyWrap implements NIST key wrapping; it wraps a content encryption key (cek) with the given block cipher.

NewCBCHMAC instantiates a new AEAD based on CBC+HMAC.

NewConcatKDF builds a KDF reader based on the given inputs.