import org.apache.commons.codec.binary.Base64;import org.junit.Test;import javax.crypto.Cipher;import java.io.ByteArrayOutputStream;import java.security.KeyFactory;import java.security.PrivateKey;import java.security.PublicKey;import java.security.spec.PKCS8EncodedKeySpec;import java.security.spec.X509EncodedKeySpec;/** * 字符串格式的密钥在未在特殊说明情况下都为BASE64编码格式
 * 由于非对称加密速度极其缓慢，一般文件不使用它来加密而是使用对称加密，
 * 非对称加密算法可以用来对对称加密的密钥加密，这样保证密钥的安全也就保证了数据的安全 */public class RSAEncrypterTest {    /**     * 加密算法RSA     */    private static final String KEY_ALGORITHM = "RSA";    /**     * 签名算法     */    private static final String CIPHER_ALGORITHM = "RSA/ECB/PKCS1Padding";//RSA是加密方法，ECB是加密模式，PKCS1Padding是填充方式    /**     * 私钥     * openssl pkcs8 -topk8 -inform PEM -in p_key.pem -outform PEM -nocrypt     */    private static final String PRIVATE_KEY = "" + "MIICdwIBADANBgkqhkiG9w0BAQEFAASCAmEwggJdAgEAAoGBAPMhwl+bv8MlboJf" + "u6W5ec0SoQQxsHn8fHmfIEvWpLc1K6uiycJfOR4nHz2hRPMquw5uuz/yWvDUkrcl" + "dabWKuI9tq2kv8Kxv1M2E+9DE+ySCKqsrAp/XZMlsy8DP+fkPEATQRv4EUkH5eD6" + "x+0BlOpbZVtXdC7vyWeGSPOwldiRAgMBAAECgYBZ5ozB34xbszaWnKF9GQURsCa7" + "r0frA1Jfglhl0ntbhxybvXjPF3i+Tob9uekN5Sn/nzA75/h6fo+1ivNi+mQmRVf2" + "6h5/kfRYy0y3RNPFOTnd6B36etUx6EpzXlpT/q+igRqlu4ts4P1heBGOdqtLlSp9" + "0KqHnjieFEgMpMschQJBAP1HdyYoSJwbYd5J3DpUIEpfjIn1MkJ2OyrEk6MQypqF" + "G8ilOJCMsFFW8oY6pPPYT9z+3NwPqxz+UWU9Kv9WjXcCQQD1vmNcAB4eg99uEExs" + "WOHEcWFNZ654K/iJ915A/c7cIJSBkoe80kqDYg+UXuY/r7ZuUi3zPSECZzs4ge8H" + "+yw3AkEAzPSM1WLZxwFdhAzO2qCC9Mw3JNg3EJMuM+CY++a1nK7EGeyhRk+iyl+K" + "p9ZC71QG5HWU8br4I+EkqsEBz1gR5wJAf8/kEaemAq0H+lDTzs5zrh5iQ0YXwjzs" + "aaWVCix3+JmhY7r4ika9ppPMEplBHAKh2cM4TviOQJe8f2llDzueBQJBAPaYpKS7" + "fTh7xi5WkJrStcNVOVgThxgmIEg3mGTztBMe87WTgUAPMr4N9gewNf+5jx231cFB" + "3gYkkPgWNOYL/2Y=";    /**     * 公钥     */    private static final String PUBLIC_KEY = "" + "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDzIcJfm7/DJW6CX7uluXnNEqEE" + "MbB5/Hx5nyBL1qS3NSurosnCXzkeJx89oUTzKrsObrs/8lrw1JK3JXWm1iriPbat" + "pL/Csb9TNhPvQxPskgiqrKwKf12TJbMvAz/n5DxAE0Eb+BFJB+Xg+sftAZTqW2Vb" + "V3Qu78lnhkjzsJXYkQIDAQAB";    /**     * RSA最大加密明文大小     */    private static final int MAX_ENCRYPT_BLOCK = 117;    /**     * RSA最大解密密文大小     */    private static final int MAX_DECRYPT_BLOCK = 128;    @Test    public void decodeTest() throws Exception {        String data = "g08ZvPcrV+k8Fh1wJ8BRGDGJWOV6pm6aq6G+Q0vgfS4SQXAXx1DI9r489cs9krBu/2Okm1g4tvqzESWHW/" + "HFqFdsgYAHluN/x6mOAx4WTYYw5XlWCYdEUhhfHeUhZi9WR0omKCrFgSfyNWx5OPy/35PSLuvl5df5E30ewejDM9+tV8" + "pAr/lDQD30BE/XwH2Hvc1EdsZ54kncK2v7lOvmMNR3PmjVsryQNnuy4kqUY5yOqi7VJlf8atOheCUe+psrnJauDc32m/" + "R99hE1UhD/R8j7Df9ZptbL/37GOpyeCyRrBpGaSjUDJ2YmiS3AnA2hoeDVV5eT72J8P5EPFYuDGQ==";        PrivateKey privateKey = getPrivateKey(PRIVATE_KEY);        Cipher vDeCipher = Cipher.getInstance(CIPHER_ALGORITHM);        vDeCipher.init(Cipher.DECRYPT_MODE, privateKey);        //私钥解密        byte[] decrypted = autoFinal(Base64.decodeBase64(data.getBytes()), vDeCipher, MAX_DECRYPT_BLOCK);        System.out.println("解密后：" + new String(decrypted, "utf-8"));    }    @Test    public void baseTest() throws Exception {        PrivateKey privateKey = getPrivateKey(PRIVATE_KEY);        PublicKey publicKey = getPublicKey(PUBLIC_KEY);        String data = "RSA加密明文最大长度117字节，解密要求密文最大长度为128字节，所以在加密和解密的过程中需要分块进行。";        //--        Cipher pEnCipher = Cipher.getInstance(CIPHER_ALGORITHM);//java默认"RSA"="RSA/ECB/PKCS1Padding"        pEnCipher.init(Cipher.ENCRYPT_MODE, publicKey);        Cipher vDeCipher = Cipher.getInstance(CIPHER_ALGORITHM);        vDeCipher.init(Cipher.DECRYPT_MODE, privateKey);        //--        Cipher vEnCipher = Cipher.getInstance(CIPHER_ALGORITHM);        vEnCipher.init(Cipher.ENCRYPT_MODE, privateKey);        Cipher pDeCipher = Cipher.getInstance(CIPHER_ALGORITHM);        pDeCipher.init(Cipher.DECRYPT_MODE, publicKey);        //公钥加密        byte[] encrypted = Base64.encodeBase64(autoFinal(data.getBytes("utf-8"), pEnCipher, MAX_ENCRYPT_BLOCK));        System.out.println("加密后：" + new String(encrypted));        //私钥解密        byte[] decrypted = autoFinal(Base64.decodeBase64(encrypted), vDeCipher, MAX_DECRYPT_BLOCK);        System.out.println("解密后：" + new String(decrypted, "utf-8"));        //私钥加密        byte[] encrypted2 = Base64.encodeBase64(autoFinal(data.getBytes("utf-8"), vEnCipher, MAX_ENCRYPT_BLOCK));        System.out.println("加密后：" + new String(encrypted2));        //公钥解密        byte[] decrypted2 = autoFinal(Base64.decodeBase64(encrypted2), pDeCipher, MAX_DECRYPT_BLOCK);        System.out.println("解密后：" + new String(decrypted2, "utf-8"));    }    /**     * 将base64编码后的公钥字符串转成PublicKey实例     */    private static PublicKey getPublicKey(String publicKey) throws Exception {        byte[] keyBytes = new Base64().decode(publicKey.getBytes());        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        return keyFactory.generatePublic(keySpec);    }    /**     * 将base64编码后的私钥字符串转成PrivateKey实例     */    private static PrivateKey getPrivateKey(String privateKey) throws Exception {        byte[] keyBytes = new Base64().decode(privateKey.getBytes());        PKCS8EncodedKeySpec keySpec = new PKCS8EncodedKeySpec(keyBytes);        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);        return keyFactory.generatePrivate(keySpec);    }    private static byte[] autoFinal(byte[] data, Cipher cipher, int blockSize) throws Exception {        int inputLen = data.length;        byte[] rs;        try (ByteArrayOutputStream out = new ByteArrayOutputStream()) {            int offSet = 0;            byte[] cache;            int i = 0;            // 对数据分段加密            while (inputLen - offSet > 0) {                if (inputLen - offSet > blockSize) {                    cache = cipher.doFinal(data, offSet, blockSize);                } else {                    cache = cipher.doFinal(data, offSet, inputLen - offSet);                }                out.write(cache, 0, cache.length);                i++;                offSet = i * blockSize;            }            rs = out.toByteArray();        }        return rs;    }}