不同程序之间经常会交换数据,我们经常采用的套路是:
假设要传输的信息是json,我们假设其为json_data,通过http传递信息为
json_data_encode=json_data&sign=md5(json_data+key)
接收方通过验证sign就知道内容有没有被篡改.
但是,这样json_data作为明码传送会让我们不太开心,所以今天的我们要介绍的aes256出马了,他是一强度很高的可逆加密算法!
aes256加密出来的内容是二进制的,不好通过http协议传输,所以我们再配合上base64转成ascii码
加密前,aes256要求字节数必须是32字节的倍数,所以使用pkcs7进行填充可以解决问题..介绍完原理,直接贴代码
写了3个版本,openresty及python和php的…请查收
1.openresty版本
local aes = require 'resty.aes'
local base64_encode = ngx.encode_base64
local base64_decode = ngx.decode_base64
local key = "a12e93c9edadeaa47eb1aeabe27dabef"
local iv = "a12e93c9edadeaa4"
-- AES 128 CBC with IV and no SALT
local cipher = aes.cipher(256,"cbc")
local aes_256_cbc_with_iv = aes:new(key,nil,cipher,{iv=iv})
local function decrypt(input)
input = base64_decode(input)
input = aes_256_cbc_with_iv:decrypt(input)
-- 取最后一个字符的ascii值
--local padding = string.byte(input,-1)
--return string.sub(input,-padding)
return input
end
local function pkcs7_padding(text)
local text_length = string.len(text)
local amount_to_pad = 32 - (text_length % 32)
if amount_to_pad == 0 then
amount_to_pad = 32
end
local pad = string.char(amount_to_pad) return text .. string.rep(pad,amount_to_pad)
end
local function encrypt (text)
text = pkcs7_padding(text)
text = aes_256_cbc_with_iv:encrypt(text)
return base64_encode(text)
end
print(decrypt(encrypt('linbc')))
2.python版本
#!/usr/bin/env python
# -*- coding: utf-8 -*-
import base64
from Crypto.Cipher import AES
import binascii
import StringIO
class PKCS7Encoder(object):
'''
RFC 2315: PKCS#7 page 21
Some content-encryption algorithms assume the
input length is a multiple of k octets, where k > 1, and
let the application define a method for handling inputs
whose lengths are not a multiple of k octets. For such
algorithms, the method shall be to pad the input at the
trailing end with k - (l mod k) octets all having value k -
(l mod k), where l is the length of the input. In other
words, the input is padded at the trailing end with one of
the following strings:
01 -- if l mod k = k-1
02 02 -- if l mod k = k-2
.
.
.
k k ... k k -- if l mod k = 0
The padding can be removed unambiguously since all input is
padded and no padding string is a suffix of another. This
padding method is well-defined if and only if k < 256;
methods for larger k are an open issue for further study.
'''
def __init__(self, k=16):
self.k = k
## @param text The padded text for which the padding is to be removed.
# @exception ValueError Raised when the input padding is missing or corrupt.
def decode(self, text):
'''
Remove the PKCS#7 padding from a text string
'''
nl = len(text)
val = int(binascii.hexlify(text[-1]), 16)
if val > self.k:
raise ValueError('Input is not padded or padding is corrupt')
l = nl - val
return text[:l]
## @param text The text to encode.
def encode(self, text):
'''
Pad an input string according to PKCS#7
'''
l = len(text)
output = StringIO.StringIO()
val = self.k - (l % self.k)
for _ in xrange(val):
output.write('%02x' % val)
return text + binascii.unhexlify(output.getvalue())
# 使用256位的AES，Python会根据传入的Key长度自动选择，长度为16时使用128位的AES
key = 'a12e93c9edadeaa47eb1aeabe27dabef'
mode = AES.MODE_CBC
#iv = '1234567812345678' # AES的CBC模式使用IV
iv = 'a12e93c9edadeaa4' # AES的CBC模式使用IV
encoder = PKCS7Encoder()
text = "This is for test."
def encrypt(data):
encryptor = AES.new(key, AES.MODE_CBC, iv)
padded_text = encoder.encode(data)
encrypted_data = encryptor.encrypt(padded_text)
return base64.b64encode(encrypted_data)
def decrypt(data):
cipher = base64.b64decode(data)
decryptor = AES.new(key, AES.MODE_CBC, iv)
plain = decryptor.decrypt(cipher)
return encoder.decode(plain)
#encrypted_text = encrypt(text)
encrypted_text = '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'
clean_text = decrypt(encrypted_text)
print "encrypted_text:", encrypted_text
print "clean_text: ", clean_text
3.php版本
<?php
//function aes256EcbPkcs7PaddingEncrypt($key, $data) {
// $padding = 16 - (strlen($data) % 16);
// $data .= str_repeat(chr($padding), $padding);
// return mcrypt_encrypt(MCRYPT_RIJNDAEL_256, hash('SHA256', $key, true), $data, MCRYPT_MODE_ECB);
//}
//
//function aes256EcbPkcs7PaddingDecrypt($key, $data) {
// $data = mcrypt_decrypt(MCRYPT_RIJNDAEL_256, hash('SHA256', $key, true), $data, MCRYPT_MODE_ECB);
// $padding = ord($data[strlen($data) - 1]);
// return substr($data, 0, -$padding);
//}
$txt="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";
$txt=base64_decode($txt);
$key="a12e93c9edadeaa47eb1aeabe27dabef";
$iv ='a12e93c9edadeaa4';
$module = mcrypt_module_open(MCRYPT_RIJNDAEL_128, '', MCRYPT_MODE_CBC, '');
mcrypt_generic_init($module, $key, $iv);
$data = mdecrypt_generic($module, $txt);
mcrypt_generic_deinit($module);
mcrypt_module_close($module);
$padding = ord($data[strlen($data) - 1]);
$result = substr($data, 0, -$padding);
echo $result;
exit();
?>