汇编代码实现HMAC-SHA256算法

根据提供的引用内容，HMAC-SHA256算法需要使用密钥生成函数HKDF_SHA256和SHA256哈希函数。由于汇编语言的实现方式与不同的处理器架构有关，因此下面提供的是x86架构下的汇编代码实现HMAC-SHA256算法的示例。

section .data
    key db 'mykey' ; 密钥
    key_len equ $-key ; 密钥长度
    message db 'mymessage' ; 消息
    message_len equ $-message ; 消息长度
section .text
    global _start

; 定义SHA256哈希函数
sha256:
    ; 参数：eax - 指向消息的指针，ebx - 消息长度，ecx - 指向哈希值的指针
    ; 返回值：无
    push ebx ; 保存消息长度
    push ecx ; 保存哈希值指针
    push eax ; 保存消息指针
    mov eax, 0x67452301
    mov ebx, 0xEFCDAB89
    mov ecx, 0x98BADCFE
    mov edx, 0x10325476
    ; 填充消息
    mov esi, eax
    mov edi, [esp+8] ; 消息指针
    mov ecx, ebx
    mov edx, ecx
    add edx, eax
    mov ebx, edx
    mov edx, 0xC3D2E1F0
    mov ebp, 0x80
    mov [edi+ebx], byte 0x80
    mov ebx, 0
    mov ecx, ebp
    sub ecx, ebx
    cmp ecx, 0x40
    jbe .Lpad
    mov ecx, 0x40
.Lpad:
    xor eax, eax
    rep stosb
    ; 处理消息
    mov eax, esi
    mov ebx, [esp+4] ; 消息长度
    mov ecx, 0
    mov edx, 0
    .Lloop:
        mov esi, eax
        mov edi, [esp+8] ; 哈希值指针
        mov ebp, ecx
        mov ebx, edx
        add ebx, 0x10
        cmp ebx, ebx
        jbe .Lend
        mov ebx, ebx
        sub ebx, edx
        cmp ebx, 0x40
        jbe .Lend
        mov ebx, 0x40
.Lend:
        mov edx, ebx
        mov ebx, eax
        add eax, edx
        push edi
        push ebp
        push esi
        push ebx
        call sha256_block
        add esp, 16
        add ecx, 0x40
        cmp ecx, [esp+4] ; 消息长度
        jb .Lloop
    ; 输出哈希值
    pop eax ; 恢复消息指针
    pop ecx ; 恢复哈希值指针
    pop ebx ; 恢复消息长度
    ret

; 定义SHA256哈希函数的内部块处理函数
sha256_block:
    ; 参数：eax - 指向消息块的指针，ebx - 指向哈希值的指针，ecx - 消息长度，edx - 哈希值长度
    ; 返回值：无
    push ebp ; 保存ebp
    mov ebp, esp ; 设置ebp
    sub esp, 0x20 ; 分配栈空间
    push ebx ; 保存哈希值指针
    push esi ; 保存消息块指针
    push edi ; 保存消息长度
    push ebp ; 保存ebp
    mov ebp, esp ; 设置ebp
    ; 初始化变量
    mov esi, [ebp+0x10] ; 消息块指针
    mov edi, [ebp+0x8] ; 哈希值指针
    mov ebx, [edi]
    mov ecx, [edi+4]
    mov edx, [edi+8]
    mov eax, [edi+12]
    mov ebp, [edi+16]
    mov esi, [edi+20]
    mov edi, [edi+24]
    ; 处理消息块
    mov ebp, 0x428A2F98
    mov edx, [esi]
    mov eax, [esi+4]
    mov ebx, [esi+8]
    mov ecx, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ebx
    mov [ebp-0x4], ecx
    mov ebx, 0x71374491
    mov edx, [esi]
    mov eax, [esi+4]
    mov ecx, [esi+8]
    mov ebp, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ecx
    mov [ebp-0x4], ebp
    mov ebp, 0xB5C0FBCF
    mov edx, [esi]
    mov eax, [esi+4]
    mov ebx, [esi+8]
    mov ecx, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ebx
    mov [ebp-0x4], ecx
    mov ebx, 0xE9B5DBA5
    mov edx, [esi]
    mov eax, [esi+4]
    mov ecx, [esi+8]
    mov ebp, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ecx
    mov [ebp-0x4], ebp
    mov ebp, 0x3956C25B
    mov edx, [esi]
    mov eax, [esi+4]
    mov ebx, [esi+8]
    mov ecx, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ebx
    mov [ebp-0x4], ecx
    mov ebx, 0x59F111F1
    mov edx, [esi]
    mov eax, [esi+4]
    mov ecx, [esi+8]
    mov ebp, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ecx
    mov [ebp-0x4], ebp
    mov ebp, 0x923F82A4
    mov edx, [esi]
    mov eax, [esi+4]
    mov ebx, [esi+8]
    mov ecx, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ebx
    mov [ebp-0x4], ecx
    mov ebx, 0xAB1C5ED5
    mov edx, [esi]
    mov eax, [esi+4]
    mov ecx, [esi+8]
    mov ebp, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ecx
    mov [ebp-0x4], ebp
    mov ebp, 0xD807AA98
    mov edx, [esi]
    mov eax, [esi+4]
    mov ebx, [esi+8]
    mov ecx, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ebx
    mov [ebp-0x4], ecx
    mov ebx, 0x12835B01
    mov edx, [esi]
    mov eax, [esi+4]
    mov ecx, [esi+8]
    mov ebp, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ecx
    mov [ebp-0x4], ebp
    mov ebp, 0x243185BE
    mov edx, [esi]
    mov eax, [esi+4]
    mov ebx, [esi+8]
    mov ecx, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ebx
    mov [ebp-0x4], ecx
    mov ebx, 0x550C7DC3
    mov edx, [esi]
    mov eax, [esi+4]
    mov ecx, [esi+8]
    mov ebp, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ecx
    mov [ebp-0x4], ebp
    mov ebp, 0x72BE5D74
    mov edx, [esi]
    mov eax, [esi+4]
    mov ebx, [esi+8]
    mov ecx, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ebx
    mov [ebp-0x4], ecx
    mov ebx, 0x80DEB1FE
    mov edx, [esi]
    mov eax, [esi+4]
    mov ecx, [esi+8]
    mov ebp, [esi+12]
    add esi, 0x10
    mov [ebp-0x10], edx
    mov [ebp-0xC], eax
    mov [ebp-0x8], ecx
    mov [ebp-0x4], ebp
    ; 更新哈希值
    mov edx, [edi]
    add [ebp-0x10], edx
    mov eax, [edi+4]
    adc [ebp-0xC], eax
    mov ebx, [edi+8]
    adc [ebp-0x8], ebx
    mov ecx, [edi+12]
    adc [ebp-0x4], ecx
    mov edx, [edi+16]
    adc [ebp+0], edx
    mov eax, [edi+20]
    adc [ebp+4], eax
    mov ebx, [edi+24]
    adc [ebp+8], ebx
    mov ecx, [edi+28]
    adc [ebp+0xC], ecx
    ; 输出哈希值
    pop ebp ; 恢复ebp
    pop edi ; 恢复消息长度
    pop esi ; 恢复消息块指针
    pop ebx ; 恢复哈希值指针
    add esp, 0x20 ; 释放栈空间
    ret

; 定义HMAC-SHA256算法
hmac_sha256:
    ; 参数：eax - 指向密钥的指针，ebx - 密钥长度，ecx - 指向消息的指针，edx - 消息长度，esi - 指向哈希值的指针
    ; 返回值：无
    push ebp ; 保存ebp
    mov ebp, esp ; 设置ebp
    sub esp, 0x20 ; 分配栈空间
    push esi ; 保存哈希值指针
    push edi ; 保存密钥指针
    push ebp ; 保存ebp
    mov ebp, esp ; 设置ebp
    ; 计算内部密钥
    mov esi, [ebp+0x10] ; 消息指针
    mov edi, [ebp+0x8] ; 密钥指针
    mov ebx, [ebp+0x14] ; 密钥长度
    cmp ebx, 0x40
    jbe .Lkeypad
    push ebx
    push edi
    call sha256
    add esp, 8
    mov edi, eax
    mov ebx, 0x20
    jmp .Lkeydone
.Lkeypad:
    mov ecx, 0x40
    sub ecx, ebx
    mov edx, ecx
    mov eax, ebx
    mov esi, 0x36
    rep stosb
    mov ecx, ebx
    mov esi, [ebp+0x8] ; 密钥指针
    add esi, ebx
    mov edx, 0x40
    sub edx, ebx
    mov eax, edx
    mov edi, esp
    rep movsb
    push edx
    push esp
    call sha256
    add esp, 8
    mov edi, eax
    mov ebx, 0x20
.Lkeydone:
    ; 计算外部密钥
    mov esi, [ebp+0x10] ; 消息指针
    mov ebx, [ebp+0x14] ; 消息长度
    mov edx, 0x40
    sub edx, ebx
    mov eax, edx
    mov edi, esp
    rep movsb