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| author |  brian m. carlson <sandals@crustytoothpaste.net> | 2018-11-14 04:09:36 +0000 |
|---|---|---|
| committer |  Junio C Hamano <gitster@pobox.com> | 2018-11-14 16:54:53 +0900 |
| commit | 13eeedb5d17ca3539600b6618d103b652ecc8ab0 (patch) | |
| tree | 4b4dd03dafa7c67d234c8f6da3e49c4a80234f76 /hash.h | |
| parent | commit-graph: convert to using the_hash_algo (diff) | |
| download | tgif-13eeedb5d17ca3539600b6618d103b652ecc8ab0.tar.xz | |
Add a base implementation of SHA-256 support
SHA-1 is weak and we need to transition to a new hash function. For
some time, we have referred to this new function as NewHash. Recently,
we decided to pick SHA-256 as NewHash. The reasons behind the choice of
SHA-256 are outlined in the thread starting at [1] and in the commit
history for the hash function transition document.
Add a basic implementation of SHA-256 based off libtomcrypt, which is in
the public domain. Optimize it and restructure it to meet our coding
standards. Pull in the update and final functions from the SHA-1 block
implementation, as we know these function correctly with all compilers.
This implementation is slower than SHA-1, but more performant
implementations will be introduced in future commits.
Wire up SHA-256 in the list of hash algorithms, and add a test that the
algorithm works correctly.
Note that with this patch, it is still not possible to switch to using
SHA-256 in Git. Additional patches are needed to prepare the code to
handle a larger hash algorithm and further test fixes are needed.
[1] https://public-inbox.org/git/20180609224913.GC38834@genre.crustytoothpaste.net/
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'hash.h')
| -rw-r--r-- | hash.h | 19 |
1 files changed, 18 insertions, 1 deletions
@@ -15,6 +15,8 @@ #include "block-sha1/sha1.h" #endif +#include "sha256/block/sha256.h" + #ifndef platform_SHA_CTX /* * platform's underlying implementation of SHA-1; could be OpenSSL, @@ -34,6 +36,18 @@ #define git_SHA1_Update platform_SHA1_Update #define git_SHA1_Final platform_SHA1_Final +#ifndef platform_SHA256_CTX +#define platform_SHA256_CTX SHA256_CTX +#define platform_SHA256_Init SHA256_Init +#define platform_SHA256_Update SHA256_Update +#define platform_SHA256_Final SHA256_Final +#endif + +#define git_SHA256_CTX platform_SHA256_CTX +#define git_SHA256_Init platform_SHA256_Init +#define git_SHA256_Update platform_SHA256_Update +#define git_SHA256_Final platform_SHA256_Final + #ifdef SHA1_MAX_BLOCK_SIZE #include "compat/sha1-chunked.h" #undef git_SHA1_Update @@ -52,12 +66,15 @@ #define GIT_HASH_UNKNOWN 0 /* SHA-1 */ #define GIT_HASH_SHA1 1 +/* SHA-256 */ +#define GIT_HASH_SHA256 2 /* Number of algorithms supported (including unknown). */ -#define GIT_HASH_NALGOS (GIT_HASH_SHA1 + 1) +#define GIT_HASH_NALGOS (GIT_HASH_SHA256 + 1) /* A suitably aligned type for stack allocations of hash contexts. */ union git_hash_ctx { git_SHA_CTX sha1; + git_SHA256_CTX sha256; }; typedef union git_hash_ctx git_hash_ctx; |