rsa

/**
 * RSA公钥加密
 *
 * @param str
 *            加密字符串
 * @param publicKey
 *            公钥
 * @return 密文
 * @throws Exception
 *             加密过程中的异常信息
 */
public static String encrypt( String str, String publicKey ) throws Exception{
    //base64编码的公钥
    byte[] decoded = Base64.decodeBase64(publicKey);
    RSAPublicKey pubKey = (RSAPublicKey) KeyFactory.getInstance("RSA").generatePublic(new X509EncodedKeySpec(decoded));
    //RSA加密
    Cipher cipher = Cipher.getInstance("RSA");
    cipher.init(Cipher.ENCRYPT_MODE, pubKey);
    String outStr = Base64.encodeBase64String(cipher.doFinal(str.getBytes("UTF-8")));
    return outStr;
}

/**
 * RSA私钥解密
 *
 * @param str
 *            加密字符串
 * @param privateKey
 *            私钥
 * @return 铭文
 * @throws Exception
 *             解密过程中的异常信息
 */
public static String decrypt(String str, String privateKey) throws Exception{
    //64位解码加密后的字符串
    byte[] inputByte = Base64.decodeBase64(str.getBytes("UTF-8"));
    //base64编码的私钥
    byte[] decoded = Base64.decodeBase64(privateKey);
    RSAPrivateKey priKey = (RSAPrivateKey) KeyFactory.getInstance("RSA").generatePrivate(new PKCS8EncodedKeySpec(decoded));
    //RSA解密
    Cipher cipher = Cipher.getInstance("RSA");
    cipher.init(Cipher.DECRYPT_MODE, priKey);
    String outStr = new String(cipher.doFinal(inputByte));
    return outStr;
}