/**
* 加密方法
* @param string $str
* @return string
*/
function encrypt($str, $screct_key)
{
//AES, 128 模式加密数据 CBC
$screct_key = base64_decode($screct_key);
$str = trim($str);
$str = addPKCS7Padding($str);
$iv = mcrypt_create_iv(mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_CBC), 1);
$encrypt_str = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $screct_key, $str, MCRYPT_MODE_CBC);
return base64_encode($encrypt_str);
}
function encryptAES128ECB($data, $key)
{
$blocks = str_split($data, 16);
$numBlocks = count($blocks);
if (strlen($blocks[$numBlocks - 1]) === 16) {
$blocks[] = addPKCS7Padding('', 16);
} else {
$blocks[$numBlocks - 1] = addPKCS7Padding($blocks[$numBlocks - 1], 16);
}
foreach ($blocks as &$block) {
$block = _encryptAES128ECB($block, $key);
}
return implode($blocks);
}
* http://cryptopals.com/sets/2/challenges/9/
*
* Implement PKCS#7 padding
*
* A block cipher transforms a fixed-sized block (usually 8 or 16 bytes) of plaintext into ciphertext. But we almost never want to transform a single block; we encrypt irregularly-sized messages.
*
* One way we account for irregularly-sized messages is by padding, creating a plaintext that is an even multiple of the blocksize. The most popular padding scheme is called PKCS#7.
*
* So: pad any block to a specific block length, by appending the number of bytes of padding to the end of the block. For instance,
* "YELLOW SUBMARINE"
*
* ... padded to 20 bytes would be:
* "YELLOW SUBMARINE\x04\x04\x04\x04"
*/
function addPKCS7Padding($data, $padTo = 16)
{
$dataLen = strlen($data);
$padLen = $padTo - $dataLen % $padTo;
return $data . str_repeat(chr($padLen), $padLen);
}
// don't output if we're included into another script.
if (!debug_backtrace()) {
$success = true;
$success &= addPKCS7Padding('YELLOW SUBMARINE', 20) === "YELLOW SUBMARINE";
$success &= addPKCS7Padding('YELLOW SUBMARINE', 10) === "YELLOW SUBMARINE";
$success &= addPKCS7Padding('YELLOW SUBMARINE', 6) === "YELLOW SUBMARINE";
// make sure a full block of padding is added when the data length is a multiple of the pad length
$success &= addPKCS7Padding('YELLOW SUBMARINE', 8) === "YELLOW SUBMARINE";
$success &= addPKCS7Padding('', 4) === "";
print $success ? "Success!\n\n" : "Failure :(\n\n";
}
