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MZ-Zyadat asked:

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I have tried to generate an encrypted text using AES algorithm In both ( Android and IPhone ) platforms but the problem is even I use the same encryption decryption algorithm (AES-128) and I use the same fixed variables ( Key , IV ,mode) but I get two deferent result for them.

I appreciate any help .

The below code presents the used encryption and decryption methods ,
Code version for Android:
- Key = “123456789abcdefg” ;
 - IV   = “1111111111111111” ;
 - Plain text = “HelloThere”;
 - Mode = “AES/CBC/NoPadding” ;

Code :
public class Crypto {
    public static String encrypt(String seed, String cleartext) throws Exception {
            byte[] rawKey = getRawKey(seed.getBytes());
            byte[] result = encrypt(rawKey, cleartext.getBytes());
            return toHex(result);
    }
    public static String decrypt(String seed, String encrypted) throws Exception {
            byte[] rawKey = getRawKey(seed.getBytes());
            byte[] enc = toByte(encrypted);
            byte[] result = decrypt(rawKey, enc);
            return new String(result);
    }
    private static byte[] getRawKey(byte[] seed) throws Exception {
            KeyGenerator kgen = KeyGenerator.getInstance(“CBC”);
            SecureRandom sr = SecureRandom.getInstance(“SHA1PRNG”);
            sr.setSeed(seed);
        kgen.init(128, sr); // 192 and 256 bits may not be available
        SecretKey skey = kgen.generateKey();
        byte[] raw = skey.getEncoded();
        return raw;
    }
    private static byte[] encrypt(byte[] raw, byte[] clear) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, “AES”);
            Cipher cipher = Cipher.getInstance(“AES”);
        cipher.init(Cipher.ENCRYPT_MODE, skeySpec);
        byte[] encrypted = cipher.doFinal(clear);
            return encrypted;
    }
    private static byte[] decrypt(byte[] raw, byte[] encrypted) throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, “AES”);
            Cipher cipher = Cipher.getInstance(“AES”);
        cipher.init(Cipher.DECRYPT_MODE, skeySpec);
        byte[] decrypted = cipher.doFinal(encrypted);
            return decrypted;
    }
    public static String toHex(String txt) {
            return toHex(txt.getBytes());
    }
    public static String fromHex(String hex) {
            return new String(toByte(hex));
    }
    public static byte[] toByte(String hexString) {
            int len = hexString.length()/2;
            byte[] result = new byte[len];
            for (int i = 0; i < len; i++)
                    result[i] = Integer.valueOf(hexString.substring(2*i, 2*i+2), 16).byteValue();
            return result;
    }
    public static String toHex(byte[] buf) {
            if (buf == null)
                    return “”;
            StringBuffer result = new StringBuffer(2*buf.length);
            for (int i = 0; i < buf.length; i++) {
                    appendHex(result, buf[i]);
            }
            return result.toString();
    }
    private final static String HEX = “0123456789ABCDEF”;
    private static void appendHex(StringBuffer sb, byte b) {
            sb.append(HEX.charAt((b»4)&0x0f)).append(HEX.charAt(b&0x0f));
    }
}
Code version for IPhone:
 
- (NSData *) transform:(CCOperation) encryptOrDecrypt data:(NSData *) inputData {
 
    NSData* secretKey = [Cipher md5:cipherKey];
    
    CCCryptorRef cryptor = NULL;
    CCCryptorStatus status = kCCSuccess;
    
    uint8_t iv[kCCBlockSizeAES128];
    memset((void *) iv, 0x0, (size_t) sizeof(iv));
    
    status = CCCryptorCreate(encryptOrDecrypt, kCCAlgorithmAES128, kCCOptionPKCS7Padding,
                             [secretKey bytes], kCCKeySizeAES128, iv, &cryptor);
    
    if (status != kCCSuccess) {
        return nil;
    }
    
    size_t bufsize = CCCryptorGetOutputLength(cryptor, (size_t)[inputData length], true);
    
    void * buf = malloc(bufsize * sizeof(uint8_t));
    memset(buf, 0x0, bufsize);
    
    size_t bufused = 0;
    size_t bytesTotal = 0;
    
    status = CCCryptorUpdate(cryptor, [inputData bytes], (size_t)[inputData length],
                             buf, bufsize, &bufused);
    
    if (status != kCCSuccess) {
        free(buf);
        CCCryptorRelease(cryptor);
        return nil;
    }
    
    bytesTotal += bufused;
    
    status = CCCryptorFinal(cryptor, buf + bufused, bufsize - bufused, &bufused);
    
    if (status != kCCSuccess) {
        free(buf);
        CCCryptorRelease(cryptor);
        return nil;
    }
    
    bytesTotal += bufused;
    
    CCCryptorRelease(cryptor);
    
    return [NSData dataWithBytesNoCopy:buf length:bytesTotal];
}
 
+ (NSData *) md5:(NSString *) stringToHash {
    
    const char *src = [stringToHash UTF8String];
    
    unsigned char result[CC_MD5_DIGEST_LENGTH];
    
    CC_MD5(src, strlen(src), result);
    
    return [NSData dataWithBytes:result length:CC_MD5_DIGEST_LENGTH];
}

Some of my references :

- http://automagical.rationalmind.net/2009/02/12/aes-interoperability-between-net-and-iphone/[^]
- http://stackoverflow.com/questions/538435/aes-interoperability-between-net-and-iphone/[^]
- http://stackoverflow.com/questions/538435/aes-interoperability-between-net-and-iphone[^]
- http://www.example-code.com/objc/rsa_encryptKey.asp[^]
- http://stackoverflow.com/questions/10031137/cccrypt-encryption-result-issue[^]
- http://stackoverflow.com/questions/10631076/how-to-encrypt-the-nsstring-value-using-des-in-iphone[^]
- http://www.code2learn.com/2011/06/encryption-and-decryption-of-data-using.html[^]
- http://code.google.com/p/aes-encryption-samples/wiki/HowToEncryptWithJava[^]
Tags: iPhone, Android, Encryption

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