diff options
Diffstat (limited to 'sha1dc/sha1.h')
| -rw-r--r-- | sha1dc/sha1.h | 90 |
1 files changed, 39 insertions, 51 deletions
diff --git a/sha1dc/sha1.h b/sha1dc/sha1.h index bd8bd92..1e4e94b 100644 --- a/sha1dc/sha1.h +++ b/sha1dc/sha1.h @@ -4,6 +4,7 @@ * See accompanying file LICENSE.txt or copy at * https://opensource.org/licenses/MIT ***/ + #ifndef SHA1DC_SHA1_H #define SHA1DC_SHA1_H @@ -11,36 +12,30 @@ extern "C" { #endif -/* uses SHA-1 message expansion to expand the first 16 words of W[] to 80 words */ -/* void sha1_message_expansion(uint32_t W[80]); */ - -/* sha-1 compression function; first version takes a message block pre-parsed as 16 32-bit integers, second version takes an already expanded message) */ -/* void sha1_compression(uint32_t ihv[5], const uint32_t m[16]); -void sha1_compression_W(uint32_t ihv[5], const uint32_t W[80]); */ +#ifndef SHA1DC_NO_STANDARD_INCLUDES +#include <stdint.h> +#endif -/* same as sha1_compression_W, but additionally store intermediate states */ +/* sha-1 compression function that takes an already expanded message, and additionally store intermediate states */ /* only stores states ii (the state between step ii-1 and step ii) when DOSTORESTATEii is defined in ubc_check.h */ void sha1_compression_states(uint32_t[5], const uint32_t[16], uint32_t[80], uint32_t[80][5]); /* -// 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]) -// where 0 <= T < 80 -// me2 is an expanded message (the expansion of an original message block XOR'ed with a disturbance vector's message block difference) -// 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 -// the function will return: -// ihvin: the reconstructed input chaining value -// ihvout: the reconstructed output chaining value +// 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]). +// Where 0 <= T < 80 +// me2 is an expanded message (the expansion of an original message block XOR'ed with a disturbance vector's message block difference.) +// 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. +// The function will return: +// ihvin: The reconstructed input chaining value. +// ihvout: The reconstructed output chaining value. */ typedef void(*sha1_recompression_type)(uint32_t*, uint32_t*, const uint32_t*, const uint32_t*); -/* table of sha1_recompression_step_0, ... , sha1_recompression_step_79 */ -/* extern sha1_recompression_type sha1_recompression_step[80];*/ - -/* a callback function type that can be set to be called when a collision block has been found: */ +/* A callback function type that can be set to be called when a collision block has been found: */ /* 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]) */ typedef void(*collision_block_callback)(uint64_t, const uint32_t*, const uint32_t*, const uint32_t*, const uint32_t*); -/* the SHA-1 context */ +/* The SHA-1 context. */ typedef struct { uint64_t total; uint32_t ihv[5]; @@ -59,30 +54,34 @@ typedef struct { uint32_t states[80][5]; } SHA1_CTX; -/* initialize SHA-1 context */ +/* Initialize SHA-1 context. */ void SHA1DCInit(SHA1_CTX*); /* -// function to enable safe SHA-1 hashing: -// collision attacks are thwarted by hashing a detected near-collision block 3 times -// think of it as extending SHA-1 from 80-steps to 240-steps for such blocks: -// the best collision attacks against SHA-1 have complexity about 2^60, -// thus for 240-steps an immediate lower-bound for the best cryptanalytic attacks would 2^180 -// an attacker would be better off using a generic birthday search of complexity 2^80 -// -// enabling safe SHA-1 hashing will result in the correct SHA-1 hash for messages where no collision attack was detected -// but it will result in a different SHA-1 hash for messages where a collision attack was detected -// this will automatically invalidate SHA-1 based digital signature forgeries -// enabled by default + Function to enable safe SHA-1 hashing: + Collision attacks are thwarted by hashing a detected near-collision block 3 times. + Think of it as extending SHA-1 from 80-steps to 240-steps for such blocks: + The best collision attacks against SHA-1 have complexity about 2^60, + thus for 240-steps an immediate lower-bound for the best cryptanalytic attacks would be 2^180. + An attacker would be better off using a generic birthday search of complexity 2^80. + + Enabling safe SHA-1 hashing will result in the correct SHA-1 hash for messages where no collision attack was detected, + but it will result in a different SHA-1 hash for messages where a collision attack was detected. + This will automatically invalidate SHA-1 based digital signature forgeries. + Enabled by default. */ void SHA1DCSetSafeHash(SHA1_CTX*, int); -/* function to disable or enable the use of Unavoidable Bitconditions (provides a significant speed up) */ -/* enabled by default */ +/* + Function to disable or enable the use of Unavoidable Bitconditions (provides a significant speed up). + Enabled by default + */ void SHA1DCSetUseUBC(SHA1_CTX*, int); -/* function to disable or enable the use of Collision Detection */ -/* enabled by default */ +/* + Function to disable or enable the use of Collision Detection. + Enabled by default. + */ void SHA1DCSetUseDetectColl(SHA1_CTX*, int); /* function to disable or enable the detection of reduced-round SHA-1 collisions */ @@ -100,23 +99,12 @@ void SHA1DCUpdate(SHA1_CTX*, const char*, size_t); /* returns: 0 = no collision detected, otherwise = collision found => warn user for active attack */ int SHA1DCFinal(unsigned char[20], SHA1_CTX*); -/* - * Same as SHA1DCFinal, but convert collision attack case into a verbose die(). - */ -void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *); - -/* - * Same as SHA1DCUpdate, but adjust types to match git's usual interface. - */ -void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, unsigned long len); - -#define platform_SHA_CTX SHA1_CTX -#define platform_SHA1_Init SHA1DCInit -#define platform_SHA1_Update git_SHA1DCUpdate -#define platform_SHA1_Final git_SHA1DCFinal - #if defined(__cplusplus) } #endif -#endif /* SHA1DC_SHA1_H */ +#ifdef SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H +#include SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H +#endif + +#endif |