Andrew's git - gitweb.git/blob

   1/***
   2* Copyright 2017 Marc Stevens <marc@marc-stevens.nl>, Dan Shumow <danshu@microsoft.com>
   3* Distributed under the MIT Software License.
   4* See accompanying file LICENSE.txt or copy at
   5* https://opensource.org/licenses/MIT
   6***/
   7
   8#ifndef SHA1DC_SHA1_H
   9#define SHA1DC_SHA1_H
  10
  11#if defined(__cplusplus)
  12extern "C" {
  13#endif
  14
  15#ifndef SHA1DC_NO_STANDARD_INCLUDES
  16#include <stdint.h>
  17#endif
  18
  19/* sha-1 compression function that takes an already expanded message, and additionally store intermediate states */
  20/* only stores states ii (the state between step ii-1 and step ii) when DOSTORESTATEii is defined in ubc_check.h */
  21void sha1_compression_states(uint32_t[5], const uint32_t[16], uint32_t[80], uint32_t[80][5]);
  22
  23/*
  24// Function type for sha1_recompression_step_T (uint32_t ihvin[5], uint32_t ihvout[5], const uint32_t me2[80], const uint32_t state[5]).
  25// Where 0 <= T < 80
  26//       me2 is an expanded message (the expansion of an original message block XOR'ed with a disturbance vector's message block difference.)
  27//       state is the internal state (a,b,c,d,e) before step T of the SHA-1 compression function while processing the original message block.
  28// The function will return:
  29//       ihvin: The reconstructed input chaining value.
  30//       ihvout: The reconstructed output chaining value.
  31*/
  32typedef void(*sha1_recompression_type)(uint32_t*, uint32_t*, const uint32_t*, const uint32_t*);
  33
  34/* A callback function type that can be set to be called when a collision block has been found: */
  35/* void collision_block_callback(uint64_t byteoffset, const uint32_t ihvin1[5], const uint32_t ihvin2[5], const uint32_t m1[80], const uint32_t m2[80]) */
  36typedef void(*collision_block_callback)(uint64_t, const uint32_t*, const uint32_t*, const uint32_t*, const uint32_t*);
  37
  38/* The SHA-1 context. */
  39typedef struct {
  40        uint64_t total;
  41        uint32_t ihv[5];
  42        unsigned char buffer[64];
  43        int found_collision;
  44        int safe_hash;
  45        int detect_coll;
  46        int ubc_check;
  47        int reduced_round_coll;
  48        collision_block_callback callback;
  49
  50        uint32_t ihv1[5];
  51        uint32_t ihv2[5];
  52        uint32_t m1[80];
  53        uint32_t m2[80];
  54        uint32_t states[80][5];
  55} SHA1_CTX;
  56
  57/* Initialize SHA-1 context. */
  58void SHA1DCInit(SHA1_CTX*);
  59
  60/*
  61    Function to enable safe SHA-1 hashing:
  62    Collision attacks are thwarted by hashing a detected near-collision block 3 times.
  63    Think of it as extending SHA-1 from 80-steps to 240-steps for such blocks:
  64        The best collision attacks against SHA-1 have complexity about 2^60,
  65        thus for 240-steps an immediate lower-bound for the best cryptanalytic attacks would be 2^180.
  66        An attacker would be better off using a generic birthday search of complexity 2^80.
  67
  68   Enabling safe SHA-1 hashing will result in the correct SHA-1 hash for messages where no collision attack was detected,
  69   but it will result in a different SHA-1 hash for messages where a collision attack was detected.
  70   This will automatically invalidate SHA-1 based digital signature forgeries.
  71   Enabled by default.
  72*/
  73void SHA1DCSetSafeHash(SHA1_CTX*, int);
  74
  75/*
  76    Function to disable or enable the use of Unavoidable Bitconditions (provides a significant speed up).
  77    Enabled by default
  78 */
  79void SHA1DCSetUseUBC(SHA1_CTX*, int);
  80
  81/*
  82    Function to disable or enable the use of Collision Detection.
  83    Enabled by default.
  84 */
  85void SHA1DCSetUseDetectColl(SHA1_CTX*, int);
  86
  87/* function to disable or enable the detection of reduced-round SHA-1 collisions */
  88/* disabled by default */
  89void SHA1DCSetDetectReducedRoundCollision(SHA1_CTX*, int);
  90
  91/* function to set a callback function, pass NULL to disable */
  92/* by default no callback set */
  93void SHA1DCSetCallback(SHA1_CTX*, collision_block_callback);
  94
  95/* update SHA-1 context with buffer contents */
  96void SHA1DCUpdate(SHA1_CTX*, const char*, size_t);
  97
  98/* obtain SHA-1 hash from SHA-1 context */
  99/* returns: 0 = no collision detected, otherwise = collision found => warn user for active attack */
 100int  SHA1DCFinal(unsigned char[20], SHA1_CTX*);
 101
 102#if defined(__cplusplus)
 103}
 104#endif
 105
 106#ifdef SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H
 107#include SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H
 108#endif
 109
 110#endif