android上的MD5和RSA的加解密

import java.io.UnsupportedEncodingException;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;public class MD5 {/* * MD5加密 */public static String getDigest(String str) {MessageDigest messageDigest = null;try {messageDigest = MessageDigest.getInstance("MD5");messageDigest.reset();messageDigest.update(str.getBytes("UTF-8"));} catch (NoSuchAlgorithmException e) {e.printStackTrace();} catch (UnsupportedEncodingException e) {e.printStackTrace();}byte[] byteArray = messageDigest.digest();StringBuffer md5StrBuff = new StringBuffer();for (int i = 0; i < byteArray.length; i++) {if (Integer.toHexString(0xFF & byteArray[i]).length() == 1)md5StrBuff.append("0").append(Integer.toHexString(0xFF & byteArray[i]));elsemd5StrBuff.append(Integer.toHexString(0xFF & byteArray[i]));}return md5StrBuff.toString().toUpperCase();}}

import java.math.BigInteger;import java.security.Key;import java.security.KeyFactory;import java.security.PublicKey;import java.security.spec.RSAPublicKeySpec;import javax.crypto.Cipher;import org.bouncycastle.jce.provider.BouncyCastleProvider;public class RSAUtil {/** * 加密 *  * @param message * @return */public static String encrypt(String message) {byte[] result = null;try {result = encrypt(message, getPublicKey());} catch (Exception e) {e.printStackTrace();}return toHexString(result);}/** * 解密 *  * @param message * @return */public static String decrypt(String message) {byte[] result = null;try {result = decrypt(message, getPublicKey());} catch (Exception e) {e.printStackTrace();}return new String(result);}/** * 加密(公钥加密、私钥加密) *  * @param message 待加密的消息 * @param key 公钥或私钥 * @return * @throws Exception */private static byte[] encrypt(String message, Key key) throws Exception {Cipher cipher = Cipher.getInstance("RSA", new BouncyCastleProvider());cipher.init(Cipher.ENCRYPT_MODE, key);// 注意中文的处理return cipher.doFinal(message.getBytes("gb2312"));}/** * 解密(如果公钥加密，则用私钥解密；如果私钥加密，则用公钥解密) *  * @param message 待解密的消息 * @param key 公钥或私钥 * @return * @throws Exception */private static byte[] decrypt(String message, Key key) throws Exception {Cipher cipher = Cipher.getInstance("RSA", new BouncyCastleProvider());cipher.init(Cipher.DECRYPT_MODE, key);return cipher.doFinal(toBytes(message));}/** * 通过模长和公钥指数获取公钥 *  * @param modulus 模长 * @param publicExponent 公钥指数 * @return * @throws Exception */public static PublicKey getPublicKey() {PublicKey publicKey = null;String modulus = "140865665237544398577638791993321201143991791099370252934699963963887058026979531275917645451893685346013654333931757603593193739776986525943697469996693704995753266331593233395038088698299308180612215713544577462613426793519824197226393059683065343801412208205295045502348474411031999124137863144916358656019";String publicExponent = "65537";BigInteger m = new BigInteger(modulus);BigInteger e = new BigInteger(publicExponent);RSAPublicKeySpec keySpec = new RSAPublicKeySpec(m, e);try {KeyFactory keyFactory = KeyFactory.getInstance("RSA", new BouncyCastleProvider());publicKey = keyFactory.generatePublic(keySpec);} catch (Exception e1) {e1.printStackTrace();}return publicKey;}private static final byte[] toBytes(String s) {byte[] bytes;bytes = new byte[s.length() / 2];for (int i = 0; i < bytes.length; i++) {bytes[i] = (byte) Integer.parseInt(s.substring(2 * i, 2 * i + 2), 16);}return bytes;}public static String toHexString(byte[] b) {StringBuilder sb = new StringBuilder(b.length * 2);for (int i = 0; i < b.length; i++) {sb.append(HEXCHAR[(b[i] & 0xf0) >>> 4]);sb.append(HEXCHAR[b[i] & 0x0f]);}return sb.toString();}private static char[] HEXCHAR = { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };}

import android.app.Activity;import android.os.Bundle;import android.util.Log;public class MainActivity extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);String info = "不知道什么时候，开始喜欢这里，每个夜里都会来这里看你。";Log.d("zhangxy",MD5.getDigest(info));// 公钥加密Log.d("zhangxy",RSAUtil.encrypt(info));// 公钥解密（经私钥加密）Log.d("zhangxy", RSAUtil.decrypt("94d5ffca913465785714348f10c57c8a0226aca2c8a5294d3a32f398c4791bee8bb37873e16a7b71ed64e40ac121ec4f4bf375b881421a17a3f10789dc543ab41c26c11ba1184b2e0328ef6d354e191f7d978bd9b984e76d310e028b3412093f7296d58d9adb7f9e4b5eb6427c369ae5e919f848c7a21b7794d5985e4d3ad10a"));}}