AES 암호화/복호화 관련

공개된 클래스: https://github.com/rnapier/RNCryptor (기존의 CommonCrypto의 wrapper)

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Use AES to encrypt with Objective-C and decrypt with PHP

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I want to use AES to encrypt a password in Objective-C, and then decrypt it in PHP, but I have two problems. I encrypt the password, but it's an NSData object, so I encode it with base64, but when I decode in PHP, the result is nil. So I can't decrypt it. I can encrypt and decrypt the password in Objective-C, so it is the PHP that is the problem, but when I encrypt with AES and then encode with base64, the results are not the same. Here is my code: PHP:     $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB);     $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND);     $key = "a16byteslongkey!";     $plaintext = "iphone";     $ciphertext = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $plaintext, MCRYPT_MODE_ECB, $iv);     $ciphertext = base64_encode($ciphertext);     echo "ciphertext: ".$ciphertext."<br/>";     $ciphertext = base64_decode($ciphertext);     $plaintext = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, $ciphertext, MCRYPT_MODE_ECB, $iv);     echo "plaintext: ".$plaintext."<br/>"; output:     ciphertext: SXNepKfh0IrlDDdkq4EdmQ==     plaintext: iphone Objective-C: (Get the full source code here: https://gist.github.com/838614)     NSString *key = @"a16byteslongkey!";     NSString *plaintext = @"iphone";     NSString *ciphertext = [plaintext AES256EncryptWithKey: key];     NSLog(@"ciphertext: %@", ciphertext);     plaintext = [ciphertext AES256DecryptWithKey: key];     NSLog(@"plaintext: %@", plaintext); output:     ciphertext: D19l3gsgXJlrLl7B2oCT6g==     plaintext: iphone i replace kCCKeySizeAES256 with kCCKeySizeAES128, and replace "kCCOptionPKCS7Padding" with "kCCOptionPKCS7Padding | kCCOptionECBMode", php objective-c encryption aes link|edit edited Aug 24 '11 at 7:38 asked Aug 23 '11 at 15:39 pcrazyc 214

4   Right off the bat it looks like you're using 128 in PHP and 256 in Obj-C... That'll be a problem. – Corey Ogburn Aug 23 '11 at 15:43 thanks for you reply, i replace kCCKeySizeAES256 with kCCKeySizeAES128, and replace "kCCOptionPKCS7Padding" with "kCCOptionPKCS7Padding & kCCOptionECBMode", but the results are also not the same. is there any detail i should change? – pcrazyc Aug 23 '11 at 16:06 2   you seem to be base64_encode-ing the resulting string in PHP but only converting it to UTF8 in Obj-C. Obviously, the results will be different. – Aleks G Aug 23 '11 at 17:43 maybe you should have a look at NSString+AESCrypt.m, it encode with base64 in "- (NSString *)AES256EncryptWithKey:(NSString *)key" – pcrazyc Aug 24 '11 at 2:01 feedback

2 Answers

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i have slove the problem. don't change the code from https://gist.github.com/838614 the key should be 32 byte. the results of encryt are not the same, but they'll be the same if you decrypt. objective-c: NSString *key = @"a16byteslongkey!a16byteslongkey!"; NSString *plaintext = @"iphone"; NSString *ciphertext = [plaintext AES256EncryptWithKey: key]; NSLog(@"ciphertext: %@", ciphertext); plaintext = [ciphertext AES256DecryptWithKey: key]; NSLog(@"plaintext: %@", plaintext); output: ciphertext: I3chV+E2XUHeLCcJAhBaJQ== plaintext: iphone php: $iv_size = mcrypt_get_iv_size(MCRYPT_RIJNDAEL_128, MCRYPT_MODE_ECB); $iv = mcrypt_create_iv($iv_size, MCRYPT_RAND); $key = 'a16byteslongkey!a16byteslongkey!'; $plaintext = "iphone"; $ciphertext = mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $key, $plaintext, MCRYPT_MODE_ECB); $base64encoded_ciphertext = base64_encode($ciphertext); echo "ciphertext: ".$base64encoded_ciphertext."<br/>"; $plaintext = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($base64encoded_ciphertext), MCRYPT_MODE_ECB); echo "plaintext: ".$plaintext."<br/>"; $base64encoded_ciphertext =  "I3chV+E2XUHeLCcJAhBaJQ=="; $plaintext = mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $key, base64_decode($base64encoded_ciphertext), MCRYPT_MODE_ECB); echo "plaintext: ".trim($plaintext); output: ciphertext: kUr+YsYtb3Uy34li/GPcjg== plaintext: iphone plaintext: iphone link|edit answered Aug 24 '11 at 8:41 pcrazyc 214