android中的加密传输
找到两种加密算法，一种MD5加密，适用于密码加密，因为这种算法不可逆；还有一种是RSA加密，这种加密是可逆的:
一、MD5加密
import java.security.MessageDigest;
public class MD5 {
private final static String[] hexDigits = { "0", "1", "2", "3", "4", "5",
"6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
/**
* 转换字节数组为16进制字串
*
* @param b
* 字节数组
* @return 16进制字串
*/
public static String byteArrayToHexString(byte[] b) {
StringBuffer resultSb = new StringBuffer();
for (int i = 0; i < b.length; i++) {
resultSb.append(byteToHexString(b[i]));
}
return resultSb.toString();
}
private static String byteToHexString(byte b) {
int n = b;
if (n < 0)
n = 256 + n;
int d1 = n / 16;
int d2 = n % 16;
return hexDigits[d1] + hexDigits[d2];
}
public static String MD5Encode(String origin) {
String resultString = null;
try {
resultString = new String(origin);
MessageDigest md = MessageDigest.getInstance("MD5");
resultString = byteArrayToHexString(md.digest(resultString
.getBytes()));
} catch (Exception ex) {
}
return resultString;
}
}
二、RSA加密
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import javax.crypto.Cipher;
/**
* RSAEncrypt
*
* @author chen
* @see
*/
public class Rsaencrype {
/**
* Main method for RSAEncrypt.
* @param args
*/
public static void main(String[] args) {
try {
Rsaencrype encrypt = new Rsaencrype();
String encryptText = "encryptText";
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
keyPairGen.initialize(1024);
KeyPair keyPair = keyPairGen.generateKeyPair();
// Generate keys
RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();
RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();
byte[] e = encrypt.encrypt(publicKey, encryptText.getBytes());
byte[] de = encrypt.decrypt(privateKey,e);
System.out.println(encrypt.bytesToString(e));
System.out.println(encrypt.bytesToString(de));
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* Change byte array to String.
* @return byte[]
*/
protected String bytesToString(byte[] encrytpByte) {
String result = "";
for (Byte bytes : encrytpByte) {
result += (char) bytes.intValue();
}
return result;
}
/**
* Encrypt String.
* @return byte[]
*/
protected byte[] encrypt(RSAPublicKey publicKey, byte[] obj) {
if (publicKey != null) {
try {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return cipher.doFinal(obj);
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}
/**
* Basic decrypt method
* @return byte[]
*/
protected byte[] decrypt(RSAPrivateKey privateKey, byte[] obj) {
if (privateKey != null) {
try {
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
return cipher.doFinal(obj);
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}
}