Find the MD4 message digest of a string of octets.
Use the ASCII encoded string “Rosetta Code” (without quotes).
You may either call an MD4 library, or implement MD4 in your language.

MD4 is an obsolete hash function that computes a 128-bit message digest that sometimes appears in obsolete protocols.

RFC 1320 specifies the MD4 algorithm. RFC 6150 declares that MD4 is obsolete.

with Ada.Text_IO;
 
with CryptAda.Digests.Message_Digests.MD4;
with CryptAda.Digests.Hashes;
with CryptAda.Pragmatics;
with CryptAda.Utils.Format;
 
procedure RC_MD4 is
   use CryptAda.Digests.Message_Digests;
   use CryptAda.Digests;
   use CryptAda.Pragmatics;
 
   function To_Byte_Array (Item : String) return Byte_Array is
      Result : Byte_Array (Item'Range);
   begin
      for I in Result'Range loop
         Result (I) := Byte (Character'Pos (Item (I)));
      end loop;
      return Result;
   end To_Byte_Array;
 
   Text    : constant String                := "Rosetta Code";
   Bytes   : constant Byte_Array            := To_Byte_Array (Text);
   Handle  : constant Message_Digest_Handle := MD4.Get_Message_Digest_Handle;
   Pointer : constant Message_Digest_Ptr    := Get_Message_Digest_Ptr (Handle);
   Hash    : Hashes.Hash;
begin
   Digest_Start  (Pointer);
   Digest_Update (Pointer, Bytes);
   Digest_End    (Pointer, Hash);
 
   Ada.Text_IO.Put_Line
     ("""" & Text & """: " & CryptAda.Utils.Format.To_Hex_String (Hashes.Get_Bytes (Hash)));
end RC_MD4;