• 密码学作业—编程能力属实拉跨了

# 明文转二进制
def bin_trans(mw):b = ""for i in mw:c =  bin(ord(i))[2:]while len(c) < 8:c = '0' + cb = b + creturn b
# 对转换后的位字符串进行补位操作 并且转为16进制
def supplement(c):length = len(c)%512if (length > 448):c = c + "1"for i in range(1,512-length + 448):c = c + "0"elif(length < 448):c = c + "1"for i in range(1,448-length):c = c + '0'else:c = c + '1' return hex(int(c,2))
# 附加长度值
def append(mw,c):length = len(mw)# 附加明文的原长度app =  hex(8*length)[2:]while(len(app)<16):app="0" + appc = c + appreturn c
# 分为16个32比特的字
def cut(w,c):for i in range(0,16):w.append("0x"+c[i*8:i*8+8])return w
# ROTL表示对32个比特的变量循环左移n比特
def ROTL(a,n):a = int(a,16)a = bin(a)a = a[2:]while len(a) < 32:a = "0" + aa = "0b" + ac = a[2:2+n]a = "0b" + a[2+n:] + ca = int(a,2)a = hex(a)return a
# 非门
def Not_func(a):a = int(a,16)a = bin(a)[2:]while len(a) < 32:a = '0' + ac = ''for ch in a:if ch == '0':c = c + '1'else:c = c + '0'c = "0b" + cc = int(c,2)c = hex(c)return c
#0 —— 19
def ch(x,y,z):c = (int(x,16) & int(y,16))^(int(Not_func(x),16) & int(z,16))return c
#20 —— 39 60 —— 79
def parity(x,y,z):c = int(x,16)^int(y,16)^int(z,16)return c
#40 —— 59
def maj(x,y,z):c = (int(x,16) & int(y,16)) ^ (int(x,16) & int(z,16)) ^ (int(y,16) & int(z,16))return c
if __name__=="__main__": #mw="Beijing University of Posts and Telecommunications"mw="State Key Laboratory of Networking and Switching State Key Laboratory of Networking and Switching"
# 初始散列值A = '0x67452301'B = '0xEFCDAB89'C = '0x98BADCFE'D = '0x10325476'E = '0xC3D2E1F0'
# 明文转二进制c = bin_trans(mw)
# 补位操作c = supplement(c)
# 附加长度值c = append(mw, c)
# 赋值给16个32比特的字c = c[2:]w = []w = cut(w,c)
# 扩充W为80个 for i in range(16,80):app=int(w[i-3],16)^int(w[i-8],16)^int(w[i-14],16)^int(w[i-16],16)app=ROTL(hex(app), 1)w.append(app)
# for循环80次for t in range(0,80):if 0 <= t & t <= 19:r = 0x5A827999a = AA = hex((int(ROTL(A,5),16) + ch(B, C, D) + int(E,16) + int(w[t],16) + r) %2 ** 32)b = BB = ac = CC = hex(int(ROTL(b, 30),16) % 2**32)d = DD = cE = delif 20 <= t & t <= 39:r = 0x6ED9EBA1a = AA = hex((int(ROTL(A,5),16) + parity(B, C, D) + int(E,16) + int(w[t],16) + r) %2 ** 32)b = BB = ac = CC = hex(int(ROTL(b, 30),16) % 2**32)d = DD = cE = delif 40 <= t & t <= 59:r = 0x8F1BBCDCa = AA = hex((int(ROTL(A,5),16) + maj(B, C, D) + int(E,16) + int(w[t],16) + r) %2 ** 32)b = BB = ac = CC = hex(int(ROTL(b, 30),16) % 2**32)d = DD = cE = delif 60 <= t & t <= 79:r = 0xCA62C1D6a = AA = hex((int(ROTL(A,5),16) + parity(B, C, D) + int(E,16) + int(w[t],16) + r) %2 ** 32)b = BB = ac = CC = hex(int(ROTL(b, 30),16) % 2**32)d = DD = cE = d
# 算出明文
A=hex((0x67452301 + int(A,16)) % 2**32)
B=hex((0xEFCDAB89 + int(B,16)) % 2**32)
C=hex((0x98BADCFE + int(C,16)) % 2**32)
D=hex((0x10325476 + int(D,16)) % 2**32)
E=hex((0xC3D2E1F0 + int(E,16)) % 2**32)
secret = A[2:]+B[2:]+C[2:]+D[2:]+E[2:]
print("sha1加密后:",secret)

• 运行结果
  
• 代码存在问题 超过一定程度的加密没有分类。懒得改了 应付作业。