module Digest: Digesttypet =string
The type of digests: 16-character strings.
val compare : t -> t -> intThe comparison function for 16-character digest, with the same
    specification as compare and the implementation
    shared with String.compare. Along with the type t, this
    function compare allows the module Digest to be passed as
    argument to the functors Set.Make and Map.Make.
val equal : t -> t -> boolThe equal function for 16-character digest.
val string : string -> tReturn the digest of the given string.
val bytes : bytes -> tReturn the digest of the given byte sequence.
val substring : string -> int -> int -> tDigest.substring s ofs len returns the digest of the substring
   of s starting at index ofs and containing len characters.
val subbytes : bytes -> int -> int -> tDigest.subbytes s ofs len returns the digest of the subsequence
    of s starting at index ofs and containing len bytes.
val channel : in_channel -> int -> tIf len is nonnegative, Digest.channel ic len reads len
   characters from channel ic and returns their digest, or raises
   End_of_file if end-of-file is reached before len characters
   are read.  If len is negative, Digest.channel ic len reads
   all characters from ic until end-of-file is reached and return
   their digest.
val file : string -> tReturn the digest of the file whose name is given.
val output : out_channel -> t -> unitWrite a digest on the given output channel.
val input : in_channel -> tRead a digest from the given input channel.
val to_hex : t -> stringReturn the printable hexadecimal representation of the given digest.
    Raise Invalid_argument if the argument is not exactly 16 bytes.
val from_hex : string -> tConvert a hexadecimal representation back into the corresponding digest.
   Raise Invalid_argument if the argument is not exactly 32 hexadecimal
   characters.