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Diffstat (limited to 'sha1dc/sha1.h')
| -rw-r--r-- | sha1dc/sha1.h | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/sha1dc/sha1.h b/sha1dc/sha1.h new file mode 100644 index 0000000000..bd8bd928fb --- /dev/null +++ b/sha1dc/sha1.h @@ -0,0 +1,122 @@ +/*** +* Copyright 2017 Marc Stevens <marc@marc-stevens.nl>, Dan Shumow <danshu@microsoft.com> +* Distributed under the MIT Software License. +* See accompanying file LICENSE.txt or copy at +* https://opensource.org/licenses/MIT +***/ +#ifndef SHA1DC_SHA1_H +#define SHA1DC_SHA1_H + +#if defined(__cplusplus) +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]); */ + +/* same as sha1_compression_W, but 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 +*/ +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: */ +/* 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 */ +typedef struct { + uint64_t total; + uint32_t ihv[5]; + unsigned char buffer[64]; + int found_collision; + int safe_hash; + int detect_coll; + int ubc_check; + int reduced_round_coll; + collision_block_callback callback; + + uint32_t ihv1[5]; + uint32_t ihv2[5]; + uint32_t m1[80]; + uint32_t m2[80]; + uint32_t states[80][5]; +} SHA1_CTX; + +/* 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 +*/ +void SHA1DCSetSafeHash(SHA1_CTX*, int); + +/* 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 */ +void SHA1DCSetUseDetectColl(SHA1_CTX*, int); + +/* function to disable or enable the detection of reduced-round SHA-1 collisions */ +/* disabled by default */ +void SHA1DCSetDetectReducedRoundCollision(SHA1_CTX*, int); + +/* function to set a callback function, pass NULL to disable */ +/* by default no callback set */ +void SHA1DCSetCallback(SHA1_CTX*, collision_block_callback); + +/* update SHA-1 context with buffer contents */ +void SHA1DCUpdate(SHA1_CTX*, const char*, size_t); + +/* obtain SHA-1 hash from SHA-1 context */ +/* 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 */ |