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I recently purchased and HTC One and test ran some code on it that is working fine on my old Moto Razr. I am getting a BadPaddingException, pad block corrupted. Encryption is needed just to hide a pass phrase in the preferences.. it's not critical. I'm just trying to obscure it a little. Here is the exception and below is the Class that I found on a forum. Encryption is my weak point. I am just not advanced enough yet to really grasp what is going on. Any help would be greatly appreciated.

10-28 15:51:26.754: W/System.err(30090): javax.crypto.BadPaddingException: pad block corrupted
10-28 15:51:26.764: W/System.err(30090):    at com.android.org.bouncycastle.jcajce.provider.symmetric.util.BaseBlockCipher.engineDoFinal(BaseBlockCipher.java:709)
10-28 15:51:26.764: W/System.err(30090):    at javax.crypto.Cipher.doFinal(Cipher.java:1111)
10-28 15:51:26.764: W/System.err(30090):    at com.seine.trophy.main.SimpleCrypto.decrypt(SimpleCrypto.java:63)
10-28 15:51:26.764: W/System.err(30090):    at com.seine.trophy.main.SimpleCrypto.decrypt(SimpleCrypto.java:36)

Java source code:

/**
* Usage:
* 
* <pre>
* String crypto = SimpleCrypto.encrypt(masterpassword, cleartext)
* ...
* String cleartext = SimpleCrypto.decrypt(masterpassword, crypto)
* </pre>
* 
* @author ferenc.hechler
*/
public class SimpleCrypto {

private final static String HEX = "0123456789ABCDEF";

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("AES");
    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 static void appendHex(StringBuffer sb, byte b) {
    sb.append(HEX.charAt((b >> 4) & 0x0f)).append(HEX.charAt(b & 0x0f));
}

}

Thanks for any help!

eis
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Todd Painton
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    Please check my (newly edited) [answer about the use of the awful `SimpleCrypto` example](http://stackoverflow.com/a/11420318/589259). Basically you are generating different keys with the `getRawKey()` method, which will result in this exception (unless you are "lucky" and the padding is correct while the plaintext is not). – Maarten Bodewes Oct 28 '13 at 23:39
  • Hey, thanks a ton. I'm glad you found my question. – Todd Painton Oct 29 '13 at 02:15

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