Android AES Decrypt decrypt(String seed, String encrypted)

Description

decrypt

Parameter

Parameter	Description
seed	a parameter
encrypted	a parameter

Declaration

public static String decrypt(String seed, String encrypted) 

Method Source Code

//package com.java2s;
import java.security.SecureRandom;
import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;

public class Main {

    public static String decrypt(String seed, String encrypted) {
        byte[] rawKey;
        try {/*  w w  w .  j  av a  2s  .  c om*/
            rawKey = getRawKey(seed.getBytes());
            byte[] enc = toByte(encrypted);
            byte[] result = decrypt(rawKey, enc);
            String coentn = new String(result);
            return coentn;
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }

    }

    private static byte[] decrypt(byte[] raw, byte[] encrypted)
            throws Exception {
        SecretKeySpec skeySpec = new SecretKeySpec(raw, "AES");
        Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
        cipher.init(Cipher.DECRYPT_MODE, skeySpec, new IvParameterSpec(
                new byte[cipher.getBlockSize()]));
        byte[] decrypted = cipher.doFinal(encrypted);
        return decrypted;
    }

    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);
        SecretKey sKey = kgen.generateKey();
        byte[] raw = sKey.getEncoded();

        return raw;
    }

    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)).byteValue();
        return result;
    }
}

Related

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2. decrypt(String encrypted)
3. decrypt(String key, String encrypted)
4. decrypt(String key, String src)
5. decrypt(String seed, String encrypted)
6. decrypt(String seed, String encrypted)
7. decrypt(String src)
8. decrypt(String src)
9. decrypt(byte[] content, String key)