------------------------------------------------------------------------------ -- -- -- GNAT LIBRARY COMPONENTS -- -- -- -- G N A T . S H A 1 -- -- -- -- B o d y -- -- -- -- Copyright (C) 2002-2006, AdaCore -- -- -- -- GNAT is free software; you can redistribute it and/or modify it under -- -- terms of the GNU General Public License as published by the Free Soft- -- -- ware Foundation; either version 2, or (at your option) any later ver- -- -- sion. GNAT is distributed in the hope that it will be useful, but WITH- -- -- OUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY -- -- or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License -- -- for more details. You should have received a copy of the GNU General -- -- Public License distributed with GNAT; see file COPYING. If not, write -- -- to the Free Software Foundation, 51 Franklin Street, Fifth Floor, -- -- Boston, MA 02110-1301, USA. -- -- -- -- As a special exception, if other files instantiate generics from this -- -- unit, or you link this unit with other files to produce an executable, -- -- this unit does not by itself cause the resulting executable to be -- -- covered by the GNU General Public License. This exception does not -- -- however invalidate any other reasons why the executable file might be -- -- covered by the GNU Public License. -- -- -- -- GNAT was originally developed by the GNAT team at New York University. -- -- Extensive contributions were provided by Ada Core Technologies Inc. -- -- -- ------------------------------------------------------------------------------ -- Note: the code for this unit is derived from GNAT.MD5 with Ada.Unchecked_Conversion; package body GNAT.SHA1 is use Interfaces; Padding : constant String := (1 => Character'Val (16#80#), 2 .. 64 => ASCII.NUL); Hex_Digit : constant array (Unsigned_32 range 0 .. 15) of Character := ('0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'); -- Look-up table for each hex digit of the Message-Digest. -- Used by function Digest (Context). type Sixteen_Words is array (Natural range 0 .. 15) of Interfaces.Unsigned_32; -- Sixteen 32-bit words, converted from block of 64 characters. -- Used in procedure Decode and Transform. procedure Decode (Block : String; X : out Sixteen_Words); -- Convert a String of 64 characters into 16 32-bit numbers -- The following functions are the four elementary components of each -- of the four round groups (0 .. 19, 20 .. 39, 40 .. 59, and 60 .. 79) -- defined in RFC 3174. function F0 (B, C, D : Unsigned_32) return Unsigned_32; pragma Inline (F0); function F1 (B, C, D : Unsigned_32) return Unsigned_32; pragma Inline (F1); function F2 (B, C, D : Unsigned_32) return Unsigned_32; pragma Inline (F2); function F3 (B, C, D : Unsigned_32) return Unsigned_32; pragma Inline (F3); procedure Transform (Ctx : in out Context; Block : String); -- Process one block of 64 characters ------------ -- Decode -- ------------ procedure Decode (Block : String; X : out Sixteen_Words) is Cur : Positive := Block'First; begin pragma Assert (Block'Length = 64); for Index in X'Range loop X (Index) := Unsigned_32 (Character'Pos (Block (Cur + 3))) + Shift_Left (Unsigned_32 (Character'Pos (Block (Cur + 2))), 8) + Shift_Left (Unsigned_32 (Character'Pos (Block (Cur + 1))), 16) + Shift_Left (Unsigned_32 (Character'Pos (Block (Cur))), 24); Cur := Cur + 4; end loop; end Decode; ------------ -- Digest -- ------------ function Digest (C : Context) return Message_Digest is Result : Message_Digest; Cur : Natural := 1; -- Index in Result where the next character will be placed Last_Block : String (1 .. 64); C1 : Context := C; procedure Convert (X : Unsigned_32); -- Put the contribution of one of the five H words of the Context in -- Result. Increments Cur. ------------- -- Convert -- ------------- procedure Convert (X : Unsigned_32) is Y : Unsigned_32 := X; begin for J in 1 .. 8 loop Y := Rotate_Left (Y, 4); Result (Cur) := Hex_Digit (Y and Unsigned_32'(16#0F#)); Cur := Cur + 1; end loop; end Convert; -- Start of processing for Digest begin -- Process characters in the context buffer, if any pragma Assert (C.Last /= C.Buffer'Last); Last_Block (1 .. C.Last) := C.Buffer (1 .. C.Last); if C.Last > 55 then Last_Block (C.Last + 1 .. 64) := Padding (1 .. 64 - C.Last); Transform (C1, Last_Block); Last_Block := (others => ASCII.NUL); else Last_Block (C.Last + 1 .. 56) := Padding (1 .. 56 - C.Last); end if; -- Add the input length (as stored in the context) as 8 characters Last_Block (57 .. 64) := (others => ASCII.NUL); declare L : Unsigned_64 := Unsigned_64 (C.Length) * 8; Idx : Positive := 64; begin while L > 0 loop Last_Block (Idx) := Character'Val (L and 16#Ff#); L := Shift_Right (L, 8); Idx := Idx - 1; end loop; end; Transform (C1, Last_Block); Convert (C1.H (0)); Convert (C1.H (1)); Convert (C1.H (2)); Convert (C1.H (3)); Convert (C1.H (4)); return Result; end Digest; function Digest (S : String) return Message_Digest is C : Context; begin Update (C, S); return Digest (C); end Digest; function Digest (A : Ada.Streams.Stream_Element_Array) return Message_Digest is C : Context; begin Update (C, A); return Digest (C); end Digest; -------- -- F0 -- -------- function F0 (B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32 is begin return (B and C) or ((not B) and D); end F0; -------- -- F1 -- -------- function F1 (B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32 is begin return B xor C xor D; end F1; -------- -- F2 -- -------- function F2 (B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32 is begin return (B and C) or (B and D) or (C and D); end F2; -------- -- F3 -- -------- function F3 (B, C, D : Interfaces.Unsigned_32) return Interfaces.Unsigned_32 renames F1; --------------- -- Transform -- --------------- procedure Transform (Ctx : in out Context; Block : String) is W : array (0 .. 79) of Interfaces.Unsigned_32; A, B, C, D, E, Temp : Interfaces.Unsigned_32; begin pragma Assert (Block'Length = 64); -- a. Divide data block into sixteen words Decode (Block, Sixteen_Words (W (0 .. 15))); -- b. Prepare working block of 80 words for T in 16 .. 79 loop -- W(t) = S^1(W(t-3) XOR W(t-8) XOR W(t-14) XOR W(t-16)) W (T) := Rotate_Left (W (T - 3) xor W (T - 8) xor W (T - 14) xor W (T - 16), 1); end loop; -- c. Set up transformation variables A := Ctx.H (0); B := Ctx.H (1); C := Ctx.H (2); D := Ctx.H (3); E := Ctx.H (4); -- d. For each of the 80 rounds, compute: -- TEMP = S^5(A) + f(t;B,C,D) + E + W(t) + K(t); -- E = D; D = C; C = S^30(B); B = A; A = TEMP; for T in 0 .. 19 loop Temp := Rotate_Left (A, 5) + F0 (B, C, D) + E + W (T) + 16#5A827999#; E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp; end loop; for T in 20 .. 39 loop Temp := Rotate_Left (A, 5) + F1 (B, C, D) + E + W (T) + 16#6ED9EBA1#; E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp; end loop; for T in 40 .. 59 loop Temp := Rotate_Left (A, 5) + F2 (B, C, D) + E + W (T) + 16#8F1BBCDC#; E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp; end loop; for T in 60 .. 79 loop Temp := Rotate_Left (A, 5) + F3 (B, C, D) + E + W (T) + 16#CA62C1D6#; E := D; D := C; C := Rotate_Left (B, 30); B := A; A := Temp; end loop; -- e. Update context: -- H0 = H0 + A, H1 = H1 + B, H2 = H2 + C, H3 = H3 + D, H4 = H4 + E Ctx.H (0) := Ctx.H (0) + A; Ctx.H (1) := Ctx.H (1) + B; Ctx.H (2) := Ctx.H (2) + C; Ctx.H (3) := Ctx.H (3) + D; Ctx.H (4) := Ctx.H (4) + E; end Transform; ------------ -- Update -- ------------ procedure Update (C : in out Context; Input : String) is Inp : constant String := C.Buffer (1 .. C.Last) & Input; Cur : Positive := Inp'First; begin C.Length := C.Length + Input'Length; while Cur + 63 <= Inp'Last loop Transform (C, Inp (Cur .. Cur + 63)); Cur := Cur + 64; end loop; C.Last := Inp'Last - Cur + 1; C.Buffer (1 .. C.Last) := Inp (Cur .. Inp'Last); end Update; procedure Update (C : in out Context; Input : Ada.Streams.Stream_Element_Array) is subtype Stream_Array is Ada.Streams.Stream_Element_Array (Input'Range); subtype Stream_String is String (1 + Integer (Input'First) .. 1 + Integer (Input'Last)); function To_String is new Ada.Unchecked_Conversion (Stream_Array, Stream_String); String_Input : constant String := To_String (Input); begin Update (C, String_Input); end Update; ----------------- -- Wide_Digest -- ----------------- function Wide_Digest (W : Wide_String) return Message_Digest is C : Context; begin Wide_Update (C, W); return Digest (C); end Wide_Digest; ----------------- -- Wide_Update -- ----------------- procedure Wide_Update (C : in out Context; Input : Wide_String) is String_Input : String (1 .. 2 * Input'Length); Cur : Positive := 1; begin for Index in Input'Range loop String_Input (Cur) := Character'Val (Unsigned_32 (Wide_Character'Pos (Input (Index))) and 16#FF#); Cur := Cur + 1; String_Input (Cur) := Character'Val (Shift_Right (Unsigned_32 (Wide_Character'Pos (Input (Index))), 8) and 16#FF#); Cur := Cur + 1; end loop; Update (C, String_Input); end Wide_Update; end GNAT.SHA1;