JAVA-RSA/DES加密兑现备忘
JAVA-RSA/DES加密实现备忘.
1. RsaEncoder.java
public class RsaEncoder {
private PublicKey rsaPublicKey;
private Cipher cipher;
// 1024位RSA加密算法中,当加密明文长度超过117个字节后,会出现异常,所以采用分段加密
private final static int PT_LEN = 117;
private final static String SPRIT_CHAR="|";//分段加密/解密,段落分割符,
private RsaEncoder(String publicKey) throws Exception{
cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
this.rsaPublicKey = this.generatePublic(publicKey);
}
private PublicKey generatePublic(String key) throws Exception {
byte[] keyBytes = Base64.decodeBase64(key);//UTF-8
X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PublicKey publicKey = keyFactory.generatePublic(keySpec);
return publicKey;
}
/**
* 加密输入的明文字符串
* 当value的字节长度大于117,将会采用分段加密,即依次对117个字节,加密,并通过"|"对段落进行分割,请解密者注意
* @param value 加密后的字符串 1024个字节长度
* @return
*/
public String encrypt(String value) throws IOException{
if(StringUtils.isEmpty(value)){
return null;
}
return encryptBySeg(value.getBytes());
}
/**
* 分段加密
* @param plainText,各个段落以'|'分割
* @return
* @throws IOException
*/
private String encryptBySeg(byte[] plainText) throws IOException{
//获取加密段落个数
int length = plainText.length;//
int mod = length %PT_LEN;//余数
int ptime = length /PT_LEN;//段数
int ptimes = (mod == 0 ? ptime : ptime +1);
StringBuffer sb = new StringBuffer();
int i = 0;
while(i < ptimes){
int from = i * PT_LEN;
int to = Math.min(length, (i+1)*PT_LEN);
byte[] temp = Arrays.copyOfRange(plainText,from, to);
sb.append(Base64.encodeBase64String(encrypt(temp)));//apache commons-codec
if(i != (ptimes - 1)){
sb.append(SPRIT_CHAR);
}
i++;
}
return sb.toString();
}
/**
* 加密
* @param plainTextArray
* @return
*/
private byte[] encrypt(byte[] plainTextArray) {
try {
cipher.init(Cipher.ENCRYPT_MODE, rsaPublicKey);
return cipher.doFinal(plainTextArray);
} catch (Exception e) {
e.printStackTrace();
}
return null;
}
/**
* 根据公钥,获取加密工具类实例
* @param publicKey
* @return
*/
public static RsaEncoder getInstance(String publicKey) throws Exception{
if(StringUtils.isEmpty(publicKey)){
return null;
}
return new RsaEncoder(publicKey);
}
/**
* 重置加密key
* @param publicKey
*/
public synchronized void reset(String publicKey) throws Exception{
this.rsaPublicKey = this.generatePublic(publicKey);
}
}
2.RsaDecoder.java
public class RsaDecoder {
private PrivateKey rsaPrivateKey;
private Cipher cipher;
private final static String SPRIT_CHAR="|";//分段加密/解密,段落分割符
private RsaDecoder(String privateKey) throws Exception{
cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
this.rsaPrivateKey = this.generatePrivate(privateKey);
}
/**
* 获取私钥,根据已经生成的合格的RSA私钥字符串,转化成RSAPrivateKey对象,(PKCS8EncodedKeySpec)
* @param key
* @return
* @throws Exception
*/
private PrivateKey generatePrivate(String key) throws Exception {
byte[] keyBytes = Base64.decodeBase64(key);
PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);
KeyFactory keyFactory = KeyFactory.getInstance("RSA");
PrivateKey privateKey = keyFactory.generatePrivate(keySpec);
return privateKey;
}
/**
* 解密
*
* @param encrypt 加密后的二进制字节
*
* @return 解密后的二进制
*/
private byte[] dencrypt(byte[] encrypt) {
try {
cipher.init(Cipher.DECRYPT_MODE, rsaPrivateKey);
byte[] decryptByteArray = cipher.doFinal(encrypt);
return decryptByteArray;
} catch (Exception e) {
throw new RuntimeException(e);
}
}
/**
* 对加密数据进行解密,自动分段
*
* @param plainText
*/
public String dencrypt(String plainTextA) {
StringTokenizer tokenizer = new StringTokenizer(plainTextA,SPRIT_CHAR);
StringBuffer sb = new StringBuffer();
while (tokenizer.hasMoreTokens()) {
byte[] tmp;
String tmpBase64Str = (String) tokenizer.nextElement();
try {
tmp = Base64.decodeBase64(getFromatBase64String(tmpBase64Str,1));
tmp = dencrypt(tmp);
sb.append(new String(tmp));
} catch (Exception e) {
e.printStackTrace();
}
}
//替换空格
return sb.toString().replace("\u0000","");
}
/**
*
* @param str
* @return
*/
public String getFromatBase64String(String str,int times){
int timesModes = (int) (Math.pow(1.5, times-1)*10);
//这个数字是由RSA1024位 及base 64增大0.5倍，具体计算公式为：rsa密钥长度/8*(1.5);
final int subLength = 172 * timesModes/10;
return str.substring(str.length()-subLength, str.length());
}
/**
* 根据私钥获取解密对象
* @param privateKey
* @return
* @throws Exception
*/
public static RsaDecoder getInstance(String privateKey) throws Exception{
if(StringUtils.isEmpty(privateKey)){
return null;
}
return new RsaDecoder(privateKey);
}
/**
* 重置加密key
* @param publicKey
*/
public void reset(String privateKey) throws Exception{
this.rsaPrivateKey = this.generatePrivate(privateKey);
}
}
3.RsaBuilder.java
public class RsaBuilder {
public static final int KEY_SIZE = 1024;
/**
* 生成密钥对,注意需要对public key进行位运算.
* @return
*/
public static KeyPair generateKeyPair(){
try {
KeyPairGenerator keyPairGen = (KeyPairGenerator) KeyPairGenerator.getInstance("RSA");
keyPairGen.initialize(KEY_SIZE, new SecureRandom());
KeyPair keyPair = keyPairGen.genKeyPair();
return keyPair;
} catch (NoSuchAlgorithmException e) {
return null;
}
}
public static void main(String[] args) throws Exception{
KeyPair keyPair = RsaBuilder.generateKeyPair();
PrivateKey privateKey = keyPair.getPrivate();
String privateKeyStr = Base64.encodeBase64String(privateKey.getEncoded());
System.out.println("----Private Key--");
System.out.println(privateKeyStr);
PublicKey publicKey = keyPair.getPublic();
String publicKeyStr = Base64.encodeBase64String(publicKey.getEncoded());
System.out.println("----Public Key--");
System.out.println(publicKeyStr);
String tmp = "123456789";
RsaEncoder rsaEncoder = RsaEncoder.getInstance(publicKeyStr);
String result = rsaEncoder.encrypt(tmp);
RsaDecoder rsaDecoder = RsaDecoder.getInstance(privateKeyStr);
System.out.println(rsaDecoder.dencrypt(result));
}
}
4.DesEncoder.java
public class DesEncoder {
private static final String DES = "DES";
private static final String PADDING = "DES/ECB/PKCS5Padding";
private static final String DEFAULT_ENCODING = "utf-8";
public final static String encrypt(String code, String key) {
try {
return Base64.encodeBase64String(encrypt(code.getBytes(DEFAULT_ENCODING), key
.getBytes(DEFAULT_ENCODING)));
} catch (Exception e) {
//
}
return null;
}
public static byte[] encrypt(byte[] src, byte[] key) throws Exception {
SecureRandom sr = new SecureRandom();
DESKeySpec dks = new DESKeySpec(key);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
SecretKey securekey = keyFactory.generateSecret(dks);
Cipher cipher = Cipher.getInstance(PADDING);
cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
return cipher.doFinal(src);
}
public final static String decrypt(String data, String key) {
try {
//base64,default-charset is UTF-8
return new String(decrypt(Base64.decodeBase64(data),
key.getBytes(DEFAULT_ENCODING)), DEFAULT_ENCODING);
} catch (Exception e) {
//
}
return null;
}
public static byte[] decrypt(byte[] src, byte[] key) throws Exception {
SecureRandom sr = new SecureRandom();
DESKeySpec dks = new DESKeySpec(key);
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
SecretKey securekey = keyFactory.generateSecret(dks);
Cipher cipher = Cipher.getInstance(PADDING);
cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
return cipher.doFinal(src);
}
public static void main(String[] args) {
String tmp = DesEncoder.encrypt("821", "yc2JffcREheFQlYFIAY5f9sY7uf*o");
System.out.print(DesEncoder.decrypt(tmp, "yc2JffcREheFQlYFIAY5f9sY7uf*o"));
}
}