RSA加密解密操作

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原文地址： /article/4065830.html

生成RSA密钥、保存到文件、从文件读取、加密、解密等操作。

import java.security.Key;
import java.security.KeyFactory;
import java.security.KeyPair;
import java.security.KeyPairGenerator;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.InvalidKeySpecException;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import javax.crypto.Cipher;
import org.apache.commons.configuration.ConfigurationException;
import org.apache.commons.configuration.PropertiesConfiguration;
import org.bouncycastle.jce.provider.BouncyCastleProvider;

public class RSATest {

public static void main(String[] args) {
try {
RSATest encrypt = new RSATest();
String encryptText = "encryptText";

// Generate keys
KeyPair keyPair = encrypt.generateKey();
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(toHexString(e));
System.out.println(toHexString(de));
} catch (Exception e) {
e.printStackTrace();
}
}

public KeyPair generateKey() throws NoSuchAlgorithmException {
KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance("RSA");
keyPairGen.initialize(1024, new SecureRandom());

KeyPair keyPair = keyPairGen.generateKeyPair();
return keyPair;
}

public void saveKey(KeyPair keyPair, String publicKeyFile,
String privateKeyFile) throws ConfigurationException {
PublicKey pubkey = keyPair.getPublic();
PrivateKey prikey = keyPair.getPrivate();

// save public key
PropertiesConfiguration publicConfig = new PropertiesConfiguration(
publicKeyFile);
publicConfig.setProperty("PULIICKEY", toHexString(pubkey.getEncoded()));
publicConfig.save();

// save private key
PropertiesConfiguration privateConfig = new PropertiesConfiguration(
privateKeyFile);
privateConfig.setProperty("PRIVATEKEY",
toHexString(prikey.getEncoded()));
privateConfig.save();
}

/**
* @param filename
* @param type：
*            1-public 0-private
* @return
* @throws ConfigurationException
* @throws NoSuchAlgorithmException
* @throws InvalidKeySpecException
*/
public Key loadKey(String filename, int type)
throws ConfigurationException, NoSuchAlgorithmException,
InvalidKeySpecException {
PropertiesConfiguration config = new PropertiesConfiguration(filename);
KeyFactory keyFactory = KeyFactory.getInstance("RSA",
new BouncyCastleProvider());

if (type == 0) {
// privateKey
String privateKeyValue = config.getString("PULIICKEY");
PKCS8EncodedKeySpec priPKCS8 = new PKCS8EncodedKeySpec(
toBytes(privateKeyValue));
PrivateKey privateKey = keyFactory.generatePrivate(priPKCS8);
return privateKey;

} else {
// publicKey
String privateKeyValue = config.getString("PRIVATEKEY");
X509EncodedKeySpec bobPubKeySpec = new X509EncodedKeySpec(
toBytes(privateKeyValue));
PublicKey publicKey = keyFactory.generatePublic(bobPubKeySpec);
return publicKey;
}
}

/**
* Encrypt String.
*
* @return byte[]
*/
protected byte[] encrypt(RSAPublicKey publicKey, byte[] data) {
if (publicKey != null) {
try {
Cipher cipher = Cipher.getInstance("RSA",
new BouncyCastleProvider());
cipher.init(Cipher.ENCRYPT_MODE, publicKey);
return cipher.doFinal(data);
} catch (Exception e) {
e.printStackTrace();
}
}
return null;
}

/**
* Basic decrypt method
*
* @return byte[]
*/
protected byte[] decrypt(RSAPrivateKey privateKey, byte[] raw) {
if (privateKey != null) {
try {
Cipher cipher = Cipher.getInstance("RSA",
new BouncyCastleProvider());
cipher.init(Cipher.DECRYPT_MODE, privateKey);
return cipher.doFinal(raw);
} catch (Exception e) {
e.printStackTrace();
}
}

return null;
}

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();
}

public 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;
}

private static char[] HEXCHAR = { '0', '1', '2', '3', '4', '5', '6', '7',
'8', '9', 'a', 'b', 'c', 'd', 'e', 'f' };

}