android平台上AES,DES加解密及问题

浏览数：34 / 时间：2015年06月11日

在使用java进行AES加密的时候，会用到如下方法：

SecureRandom sr = SecureRandom.getInstance("SHA1PRNG");

但是在android4.2以上进行加密、解密时，会报类似badPadding的异常，但是把该代码替换成一下方法则一切都OK。

SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto");

AES加密算法：

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.crypto.spec.SecretKeySpec;

public class AESUtil {

	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");
		SecureRandom sr = SecureRandom.getInstance("SHA1PRNG", "Crypto"); 
		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));
	}
}

DES加密算法

import java.io.UnsupportedEncodingException;
import java.security.Key;
import java.util.Locale;

import javax.crypto.Cipher;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESedeKeySpec;
import javax.crypto.spec.IvParameterSpec;

/**
 * DES加密
 * 
 * @author houjinyun
 * 
 */
public class DesUtils {

	private static final String KEY = "********************";
	
	/**
	 * 对字符串进行DES3加密
	 * 
	 * @param str
	 * @return 加密后的字符串，若失败则返回null
	 */
	public static String encode(String str) {
		try {
			byte[] key = KEY.getBytes("UTF-8");
			byte[] data = str.getBytes("UTF-8");
			byte[] encodedData = des3EncodeECB(key, data);
			return byte2HexString(encodedData);
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
		} catch (Exception e) {
			e.printStackTrace();
		}		
		return null;
	}

	public static String decode(String str) {
		try {
			byte[] key = KEY.getBytes("UTF-8");
			byte[] data = hexString2Byte(str);
			byte[] decodedData = des3DecodeECB(key, data);
			return new String(decodedData, "UTF-8");
		} catch(Exception e) {
			e.printStackTrace();
		}
		return null;
	}
	
	/**
	 * ECB加密,不要IV
	 * 
	 * @param key
	 *            密钥
	 * @param data
	 *            明文
	 * @return Base64编码的密文
	 * @throws Exception
	 */
	public static byte[] des3EncodeECB(byte[] key, byte[] data)
			throws Exception {
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key);
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede" + "/ECB/PKCS5Padding");
		cipher.init(Cipher.ENCRYPT_MODE, deskey);
		byte[] bOut = cipher.doFinal(data);
		return bOut;
	}

	/**
	 * ECB解密,不要IV
	 * 
	 * @param key
	 *            密钥
	 * @param data
	 *            Base64编码的密文
	 * @return 明文
	 * @throws Exception
	 */
	public static byte[] ees3DecodeECB(byte[] key, byte[] data)
			throws Exception {
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key);
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede" + "/ECB/PKCS5Padding");
		cipher.init(Cipher.DECRYPT_MODE, deskey);
		byte[] bOut = cipher.doFinal(data);
		return bOut;
	}

	/**
	 * CBC加密
	 * 
	 * @param key
	 *            密钥
	 * @param keyiv
	 *            IV
	 * @param data
	 *            明文
	 * @return Base64编码的密文
	 * @throws Exception
	 */
	public static byte[] des3EncodeCBC(byte[] key, byte[] keyiv, byte[] data)
			throws Exception {
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key);
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede" + "/CBC/PKCS5Padding");
		IvParameterSpec ips = new IvParameterSpec(keyiv);
		cipher.init(Cipher.ENCRYPT_MODE, deskey, ips);
		byte[] bOut = cipher.doFinal(data);
		return bOut;
	}

	/**
	 * CBC解密
	 * 
	 * @param key
	 *            密钥
	 * @param keyiv
	 *            IV
	 * @param data
	 *            Base64编码的密文
	 * @return 明文
	 * @throws Exception
	 */
	public static byte[] des3DecodeCBC(byte[] key, byte[] keyiv, byte[] data)
			throws Exception {
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key);
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);

		Cipher cipher = Cipher.getInstance("desede" + "/CBC/PKCS5Padding");
		IvParameterSpec ips = new IvParameterSpec(keyiv);
		cipher.init(Cipher.DECRYPT_MODE, deskey, ips);
		byte[] bOut = cipher.doFinal(data);
		return bOut;
	}

	public static byte[] des3DecodeECB(byte[] key, byte[] data)
			throws Exception {
		Key deskey = null;
		DESedeKeySpec spec = new DESedeKeySpec(key);
		SecretKeyFactory keyfactory = SecretKeyFactory.getInstance("desede");
		deskey = keyfactory.generateSecret(spec);
		Cipher cipher = Cipher.getInstance("desede" + "/ECB/PKCS5Padding");
		cipher.init(Cipher.DECRYPT_MODE, deskey);
		byte[] bOut = cipher.doFinal(data);
		return bOut;
	}
	
	private static String byte2HexString(byte[] b) {
		String a = "";
		for (int i = 0; i < b.length; i++) {
			String hex = Integer.toHexString(b[i] & 0xFF)
					.toUpperCase(Locale.US);
			if (hex.length() == 1) {
				hex = '0' + hex;
			}
			a = a + hex;
		}
		return a;
	}

	private static byte[] hexString2Byte(String str) {
		if (str == null)
			return null;
		str = str.trim();
		int len = str.length();
		if (len == 0 || len % 2 == 1)
			return null;
		byte[] b = new byte[len / 2];
		try {
			for (int i = 0; i < str.length(); i += 2) {
				b[i / 2] = (byte) Integer.decode("0x" + str.substring(i, i + 2)).intValue();
			}
			return b;
		} catch (Exception e) {
			return null;
		}
	}
	
}

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android平台上AES,DES加解密及问题