SHA256-Python-/SHA256.py at main · PYY-0617/SHA256-Python- · GitHub

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# https://zhuanlan.zhihu.com/p/278028577
# https://github.com/jingyadong/SHA256/blob/main/SHA256
# https://chat.deepseek.com/share/01f9g9l3fuu3pjov7n

class SHA256:
    def __init__(self):
        # 初始化常量（K值）和初始哈希值（H值）
        self.K = [
            0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
            0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
            0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
            0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
            0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
            0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
            0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
            0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
            0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
            0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
            0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
            0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
            0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
            0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
            0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
            0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
        ]

        self.H = [
            0x6a09e667, 0xbb67ae85, 0x3c6ef372, 0xa54ff53a,
            0x510e527f, 0x9b05688c, 0x1f83d9ab, 0x5be0cd19
        ]

    @staticmethod
    def rightrotate(x, n, size=32):
        """循环右移"""
        return (x >> n) | (x << (size - n)) & ((1 << size) - 1)

    @staticmethod
    def pad_message(message):
        """对消息进行填充"""
        if isinstance(message, str):
            message = message.encode('utf-8')

        # 原始消息长度（位）
        original_bit_len = len(message) * 8

        # 添加1和0的填充
        padded = bytearray(message)
        padded.append(0x80)  # 添加1比特

        # 填充0直到长度 ≡ 448 mod 512
        while (len(padded) * 8) % 512 != 448:
            padded.append(0x00)

        # 添加原始长度（64位大端序）
        padded.extend(original_bit_len.to_bytes(8, 'big'))

        return padded

    def hash(self, message):
        """计算SHA-256哈希值"""
        # 1. 填充消息
        padded = self.pad_message(message)

        # 2. 初始化哈希值
        h0, h1, h2, h3, h4, h5, h6, h7 = self.H

        # 3. 处理每个512位数据块
        for chunk_start in range(0, len(padded), 64):
            chunk = padded[chunk_start:chunk_start + 64]

            # 3.1 将块分解为16个32位字
            w = [0] * 64
            for i in range(16):
                w[i] = int.from_bytes(chunk[i*4:(i+1)*4], 'big')

            # 3.2 扩展消息
            for i in range(16, 64):
                s0 = self.rightrotate(w[i-15], 7) ^ self.rightrotate(w[i-15], 18) ^ (w[i-15] >> 3)
                s1 = self.rightrotate(w[i-2], 17) ^ self.rightrotate(w[i-2], 19) ^ (w[i-2] >> 10)
                w[i] = (w[i-16] + s0 + w[i-7] + s1) & 0xFFFFFFFF

            # 3.3 初始化工作变量
            a, b, c, d, e, f, g, h = h0, h1, h2, h3, h4, h5, h6, h7

            # 3.4 主循环
            for i in range(64):
                S1 = self.rightrotate(e, 6) ^ self.rightrotate(e, 11) ^ self.rightrotate(e, 25)
                ch = (e & f) ^ ((~e) & g)
                temp1 = (h + S1 + ch + self.K[i] + w[i]) & 0xFFFFFFFF

                S0 = self.rightrotate(a, 2) ^ self.rightrotate(a, 13) ^ self.rightrotate(a, 22)
                maj = (a & b) ^ (a & c) ^ (b & c)
                temp2 = (S0 + maj) & 0xFFFFFFFF

                h = g
                g = f
                f = e
                e = (d + temp1) & 0xFFFFFFFF
                d = c
                c = b
                b = a
                a = (temp1 + temp2) & 0xFFFFFFFF

            # 3.5 添加到当前哈希值
            h0 = (h0 + a) & 0xFFFFFFFF
            h1 = (h1 + b) & 0xFFFFFFFF
            h2 = (h2 + c) & 0xFFFFFFFF
            h3 = (h3 + d) & 0xFFFFFFFF
            h4 = (h4 + e) & 0xFFFFFFFF
            h5 = (h5 + f) & 0xFFFFFFFF
            h6 = (h6 + g) & 0xFFFFFFFF
            h7 = (h7 + h) & 0xFFFFFFFF

        # 4. 生成最终哈希值
        result = (h0.to_bytes(4, 'big') + h1.to_bytes(4, 'big') +
                  h2.to_bytes(4, 'big') + h3.to_bytes(4, 'big') +
                  h4.to_bytes(4, 'big') + h5.to_bytes(4, 'big') +
                  h6.to_bytes(4, 'big') + h7.to_bytes(4, 'big'))

        return result.hex()

def main():
    encoder = SHA256()

    while True:
        message = input("Enter string: ")
        print(f"Output: {encoder.hash(message)}\n")


if __name__ == "__main__":
    main()