1.算法介绍

SHA-1（英语：Secure Hash Algorithm 1，中文名：安全散列算法1）是一种密码散列函数，美国国家安全局设计，并由美国国家标准技术研究所（NIST）发布为联邦数据处理标准（FIPS）。SHA-1可以生成一个被称为消息摘要的160位（20字节）散列值，散列值通常的呈现形式为40个十六进制数

2.源码

import math

# 异或算法
def xor_func(a, b):
    a = bin(a)[2:]
    b = bin(b)[2:]
    while len(a) < 32:
        a = '0' + a
    while len(b) < 32:
        b = '0' + b
    c = ''
    for i in range(0, 32):
        if a[i] == b[i]:
            c = c + '0'
        else:
            c = c + '1'
    return c


# 与运算
def and_func(a, b):
    a = bin(a)[2:]
    b = bin(b)[2:]
    while len(a) < 32:
        a = '0' + a
    while len(b) < 32:
        b = '0' + b
    c = ''
    for i in range(0, 32):
        if a[i] == '1' and b[i] == '1':
            c = c + '1'
        else:
            c = c + '0'
    return c


# ROTL运算
def ROTL_func(a, n):
    a = a * 2 ** n
    t = int(a / 2 ** 32)
    a = a % (2 ** 32) + t
    return a


# 非门
def NOT_func(a):
    a = bin(a)[2:]
    while len(a) < 32:
        a = '0' + a
    c = ''
    for ch in a:
        if ch == '0':
            c = c + '1'
        else:
            c = c + '0'
    return c


# 步函数算法编写
def step_func(W, list):
    A = list[0]
    B = list[1]
    C = list[2]
    D = list[3]
    E = list[4]
    t = 0
    # t=0-19的计算
    while t <= 19:
        k = 0x5A827999  # K1
        if t <= 15:
            w = W[t]
        else:
            w = xor_func(int(W[t - 3], 16), int(W[t - 8], 16))  # t>15后进行新的赋值
            w = xor_func(int(w, 2), int(W[t - 14], 16))
            w = xor_func(int(w, 2), int(W[t - 16], 16))
            temp = w[0]
            w = w[1:] + temp
            w = hex(int(w, 2))
            W.append(w)
        t += 1
        x = and_func(int(B), int(C))  #
        y = NOT_func(B)  #
        z = and_func(int(y, 2), int(D))  #
        a = int(xor_func(int(x, 2), int(z, 2)), 2)  # Ch(x,y,z)
        e = E
        E = D
        D = C
        C = ROTL_func(int(B), 30) % (2 ** 32)
        B = A
        A = int(ROTL_func(int(A), 5) + a + int(e) + int(w, 16) + int(k)) % (2 ** 32)
    # t=20-39的计算
    while t <= 39 and t >= 20:
        k = 0x6ED9EBA1  # K2
        w = xor_func(int(W[t - 3], 16), int(W[t - 8], 16))
        w = xor_func(int(w, 2), int(W[t - 14], 16))
        w = xor_func(int(w, 2), int(W[t - 16], 16))
        temp = w[0]
        w = w[1:] + temp
        w = hex(int(w, 2))
        W.append(w)
        x = int(xor_func(B, C), 2)  #
        y = int(xor_func(x, D), 2)  # Parity(x,y,z)
        e = E
        E = D
        D = C
        C = ROTL_func(int(B), 30) % (2 ** 32)
        B = A
        A = int(ROTL_func(int(A), 5) + y + int(e) + int(w, 16) + int(k)) % (2 ** 32)
        t += 1
    # t=40-59的计算
    while t <= 59 and t >= 40:
        k = 0x8f1bbcdc  # K3
        w = xor_func(int(W[t - 3], 16), int(W[t - 8], 16))
        w = xor_func(int(w, 2), int(W[t - 14], 16))
        w = xor_func(int(w, 2), int(W[t - 16], 16))
        temp = w[0]
        w = w[1:] + temp
        w = hex(int(w, 2))
        W.append(w)
        x = int(and_func(B, C), 2)  #
        y = int(and_func(B, D), 2)  #
        z = int(and_func(C, D), 2)  #
        xx = int(xor_func(x, y), 2)  #
        yy = int(xor_func(xx, z), 2)  # Maj(x,y,z)
        e = E
        E = D
        D = C
        C = ROTL_func(int(B), 30) % (2 ** 32)
        B = A
        A = int(ROTL_func(int(A), 5) + yy + int(e) + int(w, 16) + int(k)) % (2 ** 32)
        t += 1
    # t=60-79的计算
    while t <= 79 and t >= 60:
        k = 0xca62c1d6  # K4
        w = xor_func(int(W[t - 3], 16), int(W[t - 8], 16))
        w = xor_func(int(w, 2), int(W[t - 14], 16))
        w = xor_func(int(w, 2), int(W[t - 16], 16))
        temp = w[0]
        w = w[1:] + temp
        w = hex(int(w, 2))
        W.append(w)
        x = int(xor_func(B, C), 2)  #
        y = int(xor_func(x, D), 2)  # Parity(x,y,z)
        e = E
        E = D
        D = C
        C = ROTL_func(int(B), 30) % (2 ** 32)
        B = A
        A = int(ROTL_func(int(A), 5) + y + int(e) + int(w, 16) + int(k)) % (2 ** 32)
        t += 1

    AA = 0x67452301
    BB = 0xEFCDAB89
    CC = 0x98BADCFE
    DD = 0x10325476
    EE = 0xC3D2E1F0

    A = (AA + A) % (2 ** 32)
    B = (BB + B) % (2 ** 32)
    C = (CC + C) % (2 ** 32)
    D = (DD + D) % (2 ** 32)
    E = (EE + E) % (2 ** 32)

    # 给列表传值
    list[0] = A
    list[1] = B
    list[2] = C
    list[3] = D
    list[4] = E


# 读取需要加密的明文
def main():
    A = 0x67452301
    B = 0xEFCDAB89
    C = 0x98BADCFE
    D = 0x10325476
    E = 0xC3D2E1F0
    list = [A, B, C, D, E]

    # 三组测试明文
    # m = 'Beijing University of Posts and Telecommunications'
    m = 'State Key Laboratory of Networking and Switching'
    # m = 'iscbupt'

    print('明文为:', m)

    W = []
    l = len(m)
    x = hex(len(m) * 8)
    n = 0  # 字符串的读取位置
    while 1:
        # 长度大于64，即所占字节大于512，需要分段处理
        if l > 64:
            m = m[n:]
            nn = 0
            for i in range(1, 64):
                if int(nn / 4) * 4 + 4 <= len(m):
                    p = p + hex(ord(m[nn]))[2:4]
                    if (nn + 1) % 4 == 0:
                        W.append(p)
                        p = ''
                    nn = nn + 1
            step_func(W, list)
            n += 64
            l -= 64
            W = []
        # 长度在56与64之间，若要字节在448到512之间，若要其字节满足与512模448同余，还需额外添加使其达到1024字节
        elif l >= 56 and l <= 64:
            mm = m[n:]
            nn = 0
            p = ''
            j = 0
            for i in range(1, 64):
                if int(nn / 4) * 4 + 4 <= len(mm):
                    p = p + hex(ord(mm[nn]))[2:4]
                    if (nn + 1) % 4 == 0:
                        W.append(p)
                        j += 1
                        p = ''
                    nn = nn + 1
                else:
                    break
            judge = 0
            for i in range(0, 4):
                if nn < len(mm):
                    p = p + hex(ord(mm[nn]))[2:4]
                    nn = nn + 1
                else:
                    if judge == 0:
                        p = p + '80'
                        judge = 1
                    elif judge == 1:
                        p = p + '00'
            W.append(p)
            j += 1
            if j == 15:
                p = '00000000'
                W.append(p)
            step_func(W, list)
            W = []
            p = '00000000'
            for i in range(0, 14):
                W.append(p)
            length = len(x) - 2
            p = ''
            for i in range(0, 16 - length):
                p = p + '0'
            p = p + x[2:]
            W.append(p[0:8])
            W.append(p[8:16])
            step_func(W, list)
            break
        # 长度小于56，字节数在0到448之间，需要补全字节使其长度为512
        elif l < 56:
            mm = m[n:]
            nn = 0
            p = ''
            for i in range(1, 56):
                if int(nn / 4) * 4 + 4 <= len(mm):
                    p = p + hex(ord(mm[nn]))[2:4]
                    if (nn + 1) % 4 == 0:
                        W.append(p)
                        p = ''
                    nn = nn + 1
                else:
                    break
            judge = 0
            for i in range(0, 4):
                if nn < len(mm):
                    p = p + hex(ord(mm[nn]))[2:4]
                    nn = nn + 1
                else:
                    if judge == 0:
                        p = p + '80'
                        judge = 1
                    elif judge == 1:
                        p = p + '00'
            W.append(p)
            for i in range(int(len(mm) / 4) + 1, 14):
                p = '00000000'
                W.append(p)
            length = len(x) - 2
            p = ''
            for i in range(0, 16 - length):
                p = p + '0'
            p = p + x[2:]
            W.append(p[0:8])
            W.append(p[8:16])
            step_func(W, list)
            break

    c = hex(list[0])[2:] + hex(list[1])[2:] + hex(list[2])[2:] + hex(list[3])[2:] + hex(list[4])[2:]
    print('密文为:', c)


main()

3.运行结果

明文为: State Key Laboratory of Networking and Switching
密文为: ea616117a3115a3caa792813ac5de2743f00b613