132 lines
3.2 KiB
NASM
132 lines
3.2 KiB
NASM
;; File: sha256.asm
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;; SHA-256 cryptographic hash
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; Implementation is based on <Wikipedia's pseudocode at https://en.wikipedia.org/wiki/SHA-2#Pseudocode>
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format COFF
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use32
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section '.data' data
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; Constant: K
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; SHA-256 round constants
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K:
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dd 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5
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dd 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174
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dd 0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da
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dd 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967
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dd 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85
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dd 0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070
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dd 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3
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dd 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
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section '.text' code
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;; Function: sha256_compute_block
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sha256_compute_block:
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push ebp
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mov ebp, esp
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leave
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ret
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;; Function: sha256_internal
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;;
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;; Parameters:
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;;
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;; [esp+8] - state
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;; [esp+12] - input buffer
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;; [esp+16] - size of the input buffer
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;;
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sha256_internal:
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push ebp
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push edi
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mov ebp, esp
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sub esp, 64+8
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mov eax, dword [ebp+16]
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xor edx, edx
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; set padlen to (len << 3)
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shld edx, eax, 3 ; 64-bit left shit
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sal eax, 3
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mov dword [ebp-(64+8)], eax
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mov dword [ebp-(64+4)], edx
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.for_block:
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cmp dword [ebp+16], 64
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jb .done
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push dword [ebp+12] ; push in
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push dword [ebp+8] ; push state
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call sha256_compute_block
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add esp, 8
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sub dword [ebp+16], 64 ; len -= 64
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add dword [ebp+12], 64 ; in += 64
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jmp .for_block
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.done:
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; ensure padding buffer is full of zero
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lea edi, [ebp-64]
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mov ecx, 16
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xor eax, eax
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rep stosd
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pop edi
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leave
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ret
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;; Function: sha256
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;;
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;; Parameters:
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;;
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;; [esp+8] - output buffer
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;; [esp+12] - input buffer
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;; [esp+16] - size of the input buffer
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;;
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public sha256
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sha256:
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push ebp
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mov ebp, esp
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sub esp, 8*4 ; uint32_t state[8]
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; setup initial state
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mov dword [ebp-8*4], 0x6a09e667
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mov dword [ebp-7*4], 0xbb67ae85
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mov dword [ebp-6*4], 0x3c6ef372
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mov dword [ebp-5*4], 0xa54ff53a
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mov dword [ebp-4*4], 0x510e527f
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mov dword [ebp-3*4], 0x9b05688c
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mov dword [ebp-2*4], 0x1f83d9ab
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mov dword [ebp-1*4], 0x5be0cd19
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;
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; copy state to uint8_t *out
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mov edx, dword [ebp+8]
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mov eax, dword [ebp-8*4]
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bswap eax
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mov dword [edx], eax ; out[0] = bswap(state[0])
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mov eax, dword [ebp-7*4]
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bswap eax
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mov dword [edx+4], eax ; out[1] = bswap(state[1])
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mov eax, dword [ebp-6*4]
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bswap eax
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mov dword [edx+8], eax ; out[2] = bswap(state[2])
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mov eax, dword [ebp-5*4]
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bswap eax
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mov dword [edx+12], eax ; out[3] = bswap(state[3])
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mov eax, dword [ebp-4*4]
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bswap eax
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mov dword [edx+16], eax ; out[4] = bswap(state[4])
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mov eax, dword [ebp-3*4]
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bswap eax
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mov dword [edx+20], eax ; out[5] = bswap(state[5])
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mov eax, dword [ebp-2*4]
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bswap eax
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mov dword [edx+24], eax ; out[6] = bswap(state[6])
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mov eax, dword [ebp-1*4]
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bswap eax
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mov dword [edx+28], eax ; out[7] = bswap(state[7])
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leave
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ret
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