python pycryptodome_Python PyCrypto(PyCryptodome) ASE实现对文件加密和解密方法
1、PyCryptodome的padding方法
pad和unpad函数是从Crypto.Util复制的。填充并修改为只使用PKCS7填充。注意，当使用PKCS7填充时，填充最后一个块是很重要的，即使它的大小是块大小的倍数，否则您将无法正确地解填充。try:
from Crypto.Util.Padding import pad, unpad
except ImportError:
from Crypto.Util.py3compat import bchr, bord
def pad(data_to_pad, block_size):
padding_len = block_size-len(data_to_pad)%block_size
padding = bchr(padding_len)*padding_len
return data_to_pad + padding
def unpad(padded_data, block_size):
pdata_len = len(padded_data)
if pdata_len % block_size:
raise ValueError("Input data is not padded")
padding_len = bord(padded_data[-1])
if padding_len<1 or padding_len>min(block_size, pdata_len):
raise ValueError("Padding is incorrect.")
if padded_data[-padding_len:]!=bchr(padding_len)*padding_len:
raise ValueError("PKCS#7 padding is incorrect.")
return padded_data[:-padding_len]
2、文件加密和解密方法
1)加密方法代码def encrypt_file(key, in_filename, out_filename=None, chunksize=64*1024):
if not out_filename:
out_filename = in_filename + '.enc'
iv = os.urandom(16)
encryptor = AES.new(key, AES.MODE_CBC, iv)
filesize = os.path.getsize(in_filename)
with open(in_filename, 'rb') as infile:
with open(out_filename, 'wb') as outfile:
outfile.write(struct.pack('
outfile.write(iv)
pos = 0
while pos < filesize:
chunk = infile.read(chunksize)
pos += len(chunk)
if pos == filesize:
chunk = pad(chunk, AES.block_size)
outfile.write(encryptor.encrypt(chunk))
2)解密方法代码def decrypt_file(key, in_filename, out_filename=None, chunksize=64*1024):
if not out_filename:
out_filename = in_filename + '.dec'
with open(in_filename, 'rb') as infile:
filesize = struct.unpack('
iv = infile.read(16)
encryptor = AES.new(key, AES.MODE_CBC, iv)
with open(out_filename, 'wb') as outfile:
encrypted_filesize = os.path.getsize(in_filename)
pos = 8 + 16 # the filesize and IV.
while pos < encrypted_filesize:
chunk = infile.read(chunksize)
pos += len(chunk)
chunk = encryptor.decrypt(chunk)
if pos == encrypted_filesize:
chunk = unpad(chunk, AES.block_size)
outfile.write(chunk)
注意：上面代码与Python2/Python3兼容，它应该可以与PyCryptodome或PyCrypto一起使用。
但是，虽然本文介绍的是PyCrypto，还是建议您更新到PyCryptodome。PyCryptodome是PyCrypto的一个分支，它公开了相同的API(因此您不需要过多地更改代码)，还提供了一些额外的特性:填充函数、经过身份验证的加密算法、KDFs等。另一方面，PyCrypto不再被维护，而且一些版本还存在基于堆的缓冲区溢出漏洞。
安装PyCryptodome使用下面命令：pip install PyCryptodome
3、完整代码import os, random, struct
from Crypto.Cipher import AES
try:
from Crypto.Util.Padding import pad, unpad
except ImportError:
from Crypto.Util.py3compat import bchr, bord
def pad(data_to_pad, block_size):
padding_len = block_size-len(data_to_pad)%block_size
padding = bchr(padding_len)*padding_len
return data_to_pad + padding
def unpad(padded_data, block_size):
pdata_len = len(padded_data)
if pdata_len % block_size:
raise ValueError("Input data is not padded")
padding_len = bord(padded_data[-1])
if padding_len<1 or padding_len>min(block_size, pdata_len):
raise ValueError("Padding is incorrect.")
if padded_data[-padding_len:]!=bchr(padding_len)*padding_len:
raise ValueError("PKCS#7 padding is incorrect.")
return padded_data[:-padding_len]
def encrypt_file(key, in_filename, out_filename=None, chunksize=64*1024):
if not out_filename:
out_filename = in_filename + '.enc'
iv = os.urandom(16)
encryptor = AES.new(key, AES.MODE_CBC, iv)
filesize = os.path.getsize(in_filename)
with open(in_filename, 'rb') as infile:
with open(out_filename, 'wb') as outfile:
outfile.write(struct.pack('
outfile.write(iv)
pos = 0
while pos < filesize:
chunk = infile.read(chunksize)
pos += len(chunk)
if pos == filesize:
chunk = pad(chunk, AES.block_size)
outfile.write(encryptor.encrypt(chunk))
def decrypt_file(key, in_filename, out_filename=None, chunksize=64*1024):
if not out_filename:
out_filename = in_filename + '.dec'
with open(in_filename, 'rb') as infile:
filesize = struct.unpack('
iv = infile.read(16)
encryptor = AES.new(key, AES.MODE_CBC, iv)
with open(out_filename, 'wb') as outfile:
encrypted_filesize = os.path.getsize(in_filename)
pos = 8 + 16 # the filesize and IV.
while pos < encrypted_filesize:
chunk = infile.read(chunksize)
pos += len(chunk)
chunk = encryptor.decrypt(chunk)
if pos == encrypted_filesize:
chunk = unpad(chunk, AES.block_size)
outfile.write(chunk)
#测试代码
if __name__=='__main__':
encrypt_file("keyskeyskeyskeys".encode('utf-8'),"/root/myfile")
decrypt_file("keyskeyskeyskeys".encode('utf-8'),"/root/myfile.enc")