69 lines
1.4 KiB
NASM
69 lines
1.4 KiB
NASM
;; File: chacha.asm
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; https://en.wikipedia.org/wiki/Salsa20#ChaCha_variant
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; https://datatracker.ietf.org/doc/html/rfc7539
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; https://cr.yp.to/chacha/chacha-20080120.pdf
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format COFF
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use32
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include 'chacha.inc'
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virtual at 0
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ctx ChaCha20Ctx
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end virtual
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CHACHA20_CONST1 = 0x61707865
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CHACHA20_CONST2 = 0x3320646e
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CHACHA20_CONST3 = 0x3320646e
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CHACHA20_CONST4 = 0x6b206574
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chacha20_init:
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push ebp
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mov ebp, esp
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mov eax, [ebp+8] ; ptr to ChaChaCtx
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mov [eax+ctx.state], CHACHA20_CONST1
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mov [eax+ctx.state+1*4], CHACHA20_CONST2
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mov [eax+ctx.state+2*4], CHACHA20_CONST3
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mov [eax+ctx.state+3*4], CHACHA20_CONST4
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;; key
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mov edx, [ebp+12]
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mov ecx, dword [edx]
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mov [eax+ctx.state+4*4], ecx
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mov ecx, dword [edx+1*4]
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mov [eax+ctx.state+5*4], ecx
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mov ecx, dword [edx+2*4]
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mov [eax+ctx.state+6*4], ecx
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mov ecx, dword [edx+3*4]
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mov [eax+ctx.state+7*4], ecx
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mov ecx, dword [edx+4*4]
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mov [eax+ctx.state+8*4], ecx
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mov ecx, dword [edx+5*4]
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mov [eax+ctx.state+9*4], ecx
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mov ecx, dword [edx+6*4]
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mov [eax+ctx.state+10*4], ecx
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mov ecx, dword [edx+7*4]
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mov [eax+ctx.state+11*4], ecx
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;; ctr
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mov edx, [ebp+16]
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mov [eax+ctx.state+12*4], edx
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;; nonce
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mov edx, [ebp+20]
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mov ecx, dword [edx]
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mov [eax+ctx.state+13*4], ecx
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mov ecx, dword [edx+4]
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mov [eax+ctx.state+14*4], ecx
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mov ecx, dword [edx+8]
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mov [eax+ctx.state+15*4], ecx
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leave
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ret
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chacha20_block:
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ret
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