StupidOS/lib/crypto/chacha20/chacha20.asm

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NASM
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2024-04-02 10:03:47 +00:00
;; File: chacha20.asm
2024-03-26 06:48:32 +00:00
; https://en.wikipedia.org/wiki/Salsa20#ChaCha_variant
; https://datatracker.ietf.org/doc/html/rfc7539
; https://cr.yp.to/chacha/chacha-20080120.pdf
format COFF
use32
include 'chacha20.inc'
virtual at 0
ctx ChaCha20Ctx
end virtual
CHACHA20_CONST1 = 0x61707865
CHACHA20_CONST2 = 0x3320646e
CHACHA20_CONST3 = 0x3320646e
CHACHA20_CONST4 = 0x6b206574
chacha20_init:
push ebp
mov ebp, esp
mov eax, [ebp+8] ; ptr to ChaChaCtx
mov [eax+ctx.state], CHACHA20_CONST1
mov [eax+ctx.state+1*4], CHACHA20_CONST2
mov [eax+ctx.state+2*4], CHACHA20_CONST3
mov [eax+ctx.state+3*4], CHACHA20_CONST4
;; key
mov edx, [ebp+12]
mov ecx, dword [edx]
mov [eax+ctx.state+4*4], ecx
mov ecx, dword [edx+1*4]
mov [eax+ctx.state+5*4], ecx
mov ecx, dword [edx+2*4]
mov [eax+ctx.state+6*4], ecx
mov ecx, dword [edx+3*4]
mov [eax+ctx.state+7*4], ecx
mov ecx, dword [edx+4*4]
mov [eax+ctx.state+8*4], ecx
mov ecx, dword [edx+5*4]
mov [eax+ctx.state+9*4], ecx
mov ecx, dword [edx+6*4]
mov [eax+ctx.state+10*4], ecx
mov ecx, dword [edx+7*4]
mov [eax+ctx.state+11*4], ecx
;; ctr
mov edx, [ebp+16]
mov [eax+ctx.state+12*4], edx
;; nonce
mov edx, [ebp+20]
mov ecx, dword [edx]
mov [eax+ctx.state+13*4], ecx
mov ecx, dword [edx+4]
mov [eax+ctx.state+14*4], ecx
mov ecx, dword [edx+8]
mov [eax+ctx.state+15*4], ecx
leave
ret
chacha20_block:
ret