DES decrypt String value - Android java.security

Android examples for java.security:DES

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Description

DES decrypt String value

Demo Code


//package com.java2s;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.spec.InvalidKeySpecException;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

public class Main {
    public static String deCrypto(String txt, String key)
            throws InvalidKeyException, InvalidKeySpecException,
            NoSuchPaddingException, IllegalBlockSizeException,
            BadPaddingException {
        DESKeySpec desKeySpec = new DESKeySpec(key.getBytes());
        SecretKeyFactory skeyFactory = null;
        Cipher cipher = null;/*from ww  w .  j av  a  2  s.c o m*/
        try {
            skeyFactory = SecretKeyFactory.getInstance("DES");
            cipher = Cipher.getInstance("DES");
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        SecretKey deskey = skeyFactory.generateSecret(desKeySpec);
        cipher.init(Cipher.DECRYPT_MODE, deskey);
        byte[] btxts = new byte[txt.length() / 2];
        for (int i = 0, count = txt.length(); i < count; i += 2) {
            btxts[i / 2] = (byte) Integer.parseInt(txt.substring(i, i + 2),
                    16);
        }
        return (new String(cipher.doFinal(btxts)));
    }
}

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