class uBlockCipher():
# 初始化选择密码算法
def __init__(self, mode='des'):
if mode.lower() == 'des':
self.a = DES()
self.blocksize = 8
elif mode.lower() == 'sm4':
self.a = SM4()
self.blocksize = 16
# 读取文件
def readFile(self, filename):
f = open(filename, 'rb')
self.data = f.read()
f.close()
# 写加密后文件
def writeFile(self, filename, ed):
f = open(filename + ed, 'wb')
f.write(self.cdata)
f.close()
# 填充，支持零填充、pkcs7
def aPadding(self, s):
if s.lower() == 'zero':
t = self.blocksize - len(self.data) % self.blocksize
for _ in range(t):
self.data += b'\x00'
elif s.lower() == 'pkcs7':
t = self.blocksize - len(self.data) % self.blocksize
pad = i2b(t, 1)
for _ in range(t):
self.data += pad
else:
raise ('没有这种填充方式。')
# 反填充
def rePadding(self, s):
if s.lower() == 'zero':
las = len(self.cdata) - 1
while self.cdata[las] == 0:
las -= 1
self.cdata = self.cdata[0:las + 1]
elif s.lower() == 'pkcs7':
num = self.cdata[-1]
self.cdata = self.cdata[0:len(self.cdata) - num]
else:
raise ('没有这种填充方式。')
# ECB模式加密
def ECB_E(self, key):
self.cdata = b''
self.a.generateKey(key)
for i in range(0, len(self.data), self.blocksize):
self.cdata += self.a.aBlockEncode(self.data[i:i + self.blocksize])
# ECB模式解密
def ECB_D(self, key):
self.cdata = b''
self.a.generateKey(key)
for i in range(0, len(self.data), self.blocksize):
self.cdata += self.a.aBlockDecode(self.data[i:i + self.blocksize])
# CBC模式加密
def CBC_E(self, key, IV):
self.cdata = b''
self.a.generateKey(key)
for i in range(0, len(self.data), self.blocksize):
tmp = b''
# print(len(self.data))
for j in range(self.blocksize):
# print(j,i+j)
tmp += i2b(IV[j] ^ self.data[i + j], 1)
IV = self.a.aBlockEncode(tmp)
self.cdata += IV
# CBC模式解密
def CBC_D(self, key, IV):
self.cdata = b''
self.a.generateKey(key)
for i in range(0, len(self.data), self.blocksize):
tmp = self.a.aBlockDecode(self.data[i:i + self.blocksize])
for j in range(self.blocksize):
self.cdata += i2b(IV[j] ^ tmp[j], 1)
IV = self.data[i:i + self.blocksize]
# CFB模式加密
def CFB_E(self, key, IV, cfb_s=8):
if cfb_s % 8 != 0 or cfb_s > self.blocksize * 8:
raise ('明文分组长度出错。')
self.cdata = b''
self.a.generateKey(key)
for i in range(0, len(self.data), cfb_s // 8):
tmp = b''
eIV = self.a.aBlockEncode(IV)
for j in range(cfb_s // 8):
tmp += i2b(eIV[j] ^ self.data[i + j], 1)
IV = IV[cfb_s // 8:] + tmp
self.cdata += tmp
# CFB模式解密
def CFB_D(self, key, IV, cfb_s=8):
if cfb_s % 8 != 0 or cfb_s > self.blocksize * 8:
raise ('明文分组长度出错。')
self.cdata = b''
self.a.generateKey(key)
for i in range(0, len(self.data), cfb_s // 8):
tmp = b''
eIV = self.a.aBlockEncode(IV)
for j in range(cfb_s // 8):
tmp += i2b(eIV[j] ^ self.data[i + j], 1)
IV = IV[cfb_s // 8:] + self.data[i:i + cfb_s // 8]
self.cdata += tmp
# 文件加密
def encryptFile(self,
filename,
key,
IV,
mode='cbc',
padding='pkcs7',
coding='base64',
cfb_s=8):
self.readFile(filename)
self.aPadding(padding)
if mode.lower() == 'ecb':
print('请注意，ECB模式可能不安全！')
self.ECB_E(key)
elif mode.lower() == 'cbc':
self.CBC_E(key, IV)
elif mode.lower() == 'cfb':
self.CFB_E(key, IV, cfb_s)
else:
raise ('没有这种工作模式。')
if coding.lower() == 'base64':
self.cdata = base64.b64encode(self.cdata)
elif coding.lower() == 'hex':
self.cdata = ''.join([hex(i)[2:]
for i in self.cdata]).encode('utf-8')
else:
raise ('没有这种编码方案')
self.writeFile(filename, '.encrypt')
# 文件解密
def decryptFile(self,
filename,
key,
IV,
mode='cbc',
padding='pkcs7',
coding='base64',
cfb_s=8):
self.readFile(filename)
if coding.lower() == 'base64':
self.data = base64.b64decode(self.data)
elif coding.lower() == 'hex':
tmp = b''
for i in range(0, len(self.data), 2):
tmp += i2b(int(self.data[i:i + 2].decode('utf-8'), 16), 1)
self.data = tmp
else:
raise ('没有这种编码方案')
if mode.lower() == 'ecb':
self.ECB_D(key)
elif mode.lower() == 'cbc':
self.CBC_D(key, IV)
elif mode.lower() == 'cfb':
self.CFB_D(key, IV, cfb_s)
else:
raise ('没有这种工作模式。')
self.rePadding(padding)
self.writeFile(filename, '.decrypt')
# 测试模式
def show(self):
s = b'zzzzzzzz'
self.encryptFile('BlockCipher\\123.txt',
s,
s,
mode='cfb',
padding='pkcs7',
coding='base64')
self.decryptFile('BlockCipher\\123.txt.encrypt',
s,
s,
mode='cfb',
padding='pkcs7',
coding='base64')
