class type digest =object
..end
method name : string
The name conventionally follows the <uppercasestring>-<size>
format,
e.g. "MD5-128", "SHA1-160", or "SHA2-256".
method iana_hash_fn : iana_hash_fn option
Whether registered at IANA, and if so, which ID we use here
method iana_name : string option
The name as registered by IANA (if registered)
method oid : int array option
The OID (if registered)
method size : int
The size of the digest string in bytes
method block_length : int
The block length of the hash function (for HMAC) in bytes
method create : unit -> digest_ctx
Start digestion