DeriveECDHES derives a shared encryption key using ECDH/ConcatKDF as described in JWE/JWA. It is an error to call this function with a private/public key that are not on the same curve. Callers must ensure that the keys are valid before calling this function. Output size may be at most 1<<16 bytes (64 KiB).
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.