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
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')))
接着是python版本的
#!/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
再来个php版本的
<?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(); ?>
php果然是…很省事的语言..看他多简短啊.
