非对称加密

有公钥与私钥 你拿着公钥加密报文 传给对方 对方拿着私钥解密生成的报文

生成一对儿公钥与私钥如图

 公钥 私钥 加密后的密文

 

通过私钥 加密一个密码

通过公钥 及加密后的密码传给服务端进行解密与明文

 

参考代码

ConfigTools 

package com.qbsea.rsa;

import javax.crypto.Cipher;
import java.io.ByteArrayOutputStream;
import java.io.Closeable;
import java.io.FileInputStream;
import java.security.*;
import java.security.cert.Certificate;
import java.security.cert.CertificateFactory;
import java.security.interfaces.RSAPrivateKey;
import java.security.interfaces.RSAPublicKey;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.RSAPrivateKeySpec;
import java.security.spec.RSAPublicKeySpec;
import java.security.spec.X509EncodedKeySpec;


public class ConfigTools {

    private static final String DEFAULT_PRIVATE_KEY_STRING = "MIIBVAIBADANBgkqhkiG9w0BAQEFAASCAT4wggE6AgEAAkEAocbCrurZGbC5GArEHKlAfDSZi7gFBnd4yxOt0rwTqKBFzGyhtQLu5PRKjEiOXVa95aeIIBJ6OhC2f8FjqFUpawIDAQABAkAPejKaBYHrwUqUEEOe8lpnB6lBAsQIUFnQI/vXU4MV+MhIzW0BLVZCiarIQqUXeOhThVWXKFt8GxCykrrUsQ6BAiEA4vMVxEHBovz1di3aozzFvSMdsjTcYRRo82hS5Ru2/OECIQC2fAPoXixVTVY7bNMeuxCP4954ZkXp7fEPDINCjcQDywIgcc8XLkkPcs3Jxk7uYofaXaPbg39wuJpEmzPIxi3k0OECIGubmdpOnin3HuCP/bbjbJLNNoUdGiEmFL5hDI4UdwAdAiEAtcAwbm08bKN7pwwvyqaCBC//VnEWaq39DCzxr+Z2EIk=";
    public static final String DEFAULT_PUBLIC_KEY_STRING = "MFwwDQYJKoZIhvcNAQEBBQADSwAwSAJBAKHGwq7q2RmwuRgKxBypQHw0mYu4BQZ3eMsTrdK8E6igRcxsobUC7uT0SoxIjl1WveWniCASejoQtn/BY6hVKWsCAwEAAQ==";
    public static void main(String[] args) throws Exception {
        String password = "123456";
        String privateKey = "MIIBVQIBADANBgkqhkiG9w0BAQEFAASCAT8wggE7AgEAAkEAvVbW0LcA5ZgwCrASDKnassdJQ75QvOG20V1I2PMu9aqhAyUYSm+ohjtMlP0Pxp8xVetxJ/vsGMc8rqL+4kWXWwIDAQABAkEAuhPWGllAMGRZEqfnlTp5DKp+fm1Tu824dhpPtaeJxzSxE3n/PCo3ugtRR/BFOnjFGLNAagWYBEjXrPAkK186gQIhAOIaRRlCZ84odosFRwp824OpML2UNipsD5T+d2BUSnl5AiEA1mAaRRaOZ1aqaitiZ7Ca0hOn34AIxvIQWo6Hkp3dtnMCIEBV6UN+ubrXmKOGJOi/DlcwVUYcXi1EAksK/TzTvz1BAiEAq7D8WSjflFQM2Es23OTMmkOzx4S7gtqLznsoiXx1/ZECIAaXFDbbSCyQ196mYAgrJ9YPAiI8MofUP9eOTa5cVkKf";
        String key = getPasswordEncriptByPrivateKey( privateKey,  password);
        System.out.println(key);
    }
    public static void main1(String[] args) throws Exception {

//        String password = args[0];
        String password = "123456";
//        String[] arr = genKeyPair(512);
//        System.out.println("privateKey:" + arr[0]);
//        System.out.println("publicKey:" + arr[1]);
//        System.out.println("password:" + encrypt(arr[0], password));

        String privateKey = "MIIBVQIBADANBgkqhkiG9w0BAQEFAASCAT8wggE7AgEAAkEAvVbW0LcA5ZgwCrASDKnassdJQ75QvOG20V1I2PMu9aqhAyUYSm+ohjtMlP0Pxp8xVetxJ/vsGMc8rqL+4kWXWwIDAQABAkEAuhPWGllAMGRZEqfnlTp5DKp+fm1Tu824dhpPtaeJxzSxE3n/PCo3ugtRR/BFOnjFGLNAagWYBEjXrPAkK186gQIhAOIaRRlCZ84odosFRwp824OpML2UNipsD5T+d2BUSnl5AiEA1mAaRRaOZ1aqaitiZ7Ca0hOn34AIxvIQWo6Hkp3dtnMCIEBV6UN+ubrXmKOGJOi/DlcwVUYcXi1EAksK/TzTvz1BAiEAq7D8WSjflFQM2Es23OTMmkOzx4S7gtqLznsoiXx1/ZECIAaXFDbbSCyQ196mYAgrJ9YPAiI8MofUP9eOTa5cVkKf";
        String key = getPasswordEncriptByPrivateKey( privateKey,  password);
        System.out.println(key);
    }
    public static String getPasswordEncriptByPrivateKey(String privateKey,String password) throws Exception {
        String encrypt = encrypt(privateKey, password);
        return encrypt;
    }

    public static String decrypt(String cipherText) throws Exception {
        return decrypt((String) null, cipherText);
    }

    public static String decrypt(String publicKeyText, String cipherText)
            throws Exception {
        PublicKey publicKey = getPublicKey(publicKeyText);

        return decrypt(publicKey, cipherText);
    }

    public static PublicKey getPublicKeyByX509(String x509File) {
        if (x509File == null || x509File.length() == 0) {
            return ConfigTools.getPublicKey(null);
        }

        FileInputStream in = null;
        try {
            in = new FileInputStream(x509File);

            CertificateFactory factory = CertificateFactory
                    .getInstance("X.509");
            Certificate cer = factory.generateCertificate(in);
            return cer.getPublicKey();
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to get public key", e);
        } finally {
//            JdbcUtils.close(in);
            close(in);
        }
    }

    public static PublicKey getPublicKey(String publicKeyText) {
        if (publicKeyText == null || publicKeyText.length() == 0) {
            publicKeyText = ConfigTools.DEFAULT_PUBLIC_KEY_STRING;
        }

        try {
            byte[] publicKeyBytes = Base64.base64ToByteArray(publicKeyText);
            X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(
                    publicKeyBytes);

            KeyFactory keyFactory = KeyFactory.getInstance("RSA", "SunRsaSign");
            return keyFactory.generatePublic(x509KeySpec);
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to get public key", e);
        }
    }

    public static PublicKey getPublicKeyByPublicKeyFile(String publicKeyFile) {
        if (publicKeyFile == null || publicKeyFile.length() == 0) {
            return ConfigTools.getPublicKey(null);
        }

        FileInputStream in = null;
        try {
            in = new FileInputStream(publicKeyFile);
            ByteArrayOutputStream out = new ByteArrayOutputStream();
            int len = 0;
            byte[] b = new byte[512 / 8];
            while ((len = in.read(b)) != -1) {
                out.write(b, 0, len);
            }

            byte[] publicKeyBytes = out.toByteArray();
            X509EncodedKeySpec spec = new X509EncodedKeySpec(publicKeyBytes);
            KeyFactory factory = KeyFactory.getInstance("RSA", "SunRsaSign");
            return factory.generatePublic(spec);
        } catch (Exception e) {
            throw new IllegalArgumentException("Failed to get public key", e);
        } finally {
//            JdbcUtils.close(in);
            close(in);
        }
    }

    public static String decrypt(PublicKey publicKey, String cipherText)
            throws Exception {
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        try {
            cipher.init(Cipher.DECRYPT_MODE, publicKey);
        } catch (InvalidKeyException e) {
            // 因为 IBM JDK 不支持私钥加密, 公钥解密, 所以要反转公私钥
            // 也就是说对于解密, 可以通过公钥的参数伪造一个私钥对象欺骗 IBM JDK
            RSAPublicKey rsaPublicKey = (RSAPublicKey) publicKey;
            RSAPrivateKeySpec spec = new RSAPrivateKeySpec(rsaPublicKey.getModulus(), rsaPublicKey.getPublicExponent());
            Key fakePrivateKey = KeyFactory.getInstance("RSA").generatePrivate(spec);
            cipher = Cipher.getInstance("RSA"); //It is a stateful object. so we need to get new one.
            cipher.init(Cipher.DECRYPT_MODE, fakePrivateKey);
        }

        if (cipherText == null || cipherText.length() == 0) {
            return cipherText;
        }

        byte[] cipherBytes = Base64.base64ToByteArray(cipherText);
        byte[] plainBytes = cipher.doFinal(cipherBytes);

        return new String(plainBytes);
    }

    public static String encrypt(String plainText) throws Exception {
        return encrypt((String) null, plainText);
    }

    public static String encrypt(String key, String plainText) throws Exception {
        if (key == null) {
            key = DEFAULT_PRIVATE_KEY_STRING;
        }

        byte[] keyBytes = Base64.base64ToByteArray(key);
        return encrypt(keyBytes, plainText);
    }

    public static String encrypt(byte[] keyBytes, String plainText)
            throws Exception {
        PKCS8EncodedKeySpec spec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory factory = KeyFactory.getInstance("RSA", "SunRsaSign");
        PrivateKey privateKey = factory.generatePrivate(spec);
        Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
        try {
            cipher.init(Cipher.ENCRYPT_MODE, privateKey);
        } catch (InvalidKeyException e) {
            //For IBM JDK, 原因请看解密方法中的说明
            RSAPrivateKey rsaPrivateKey = (RSAPrivateKey) privateKey;
            RSAPublicKeySpec publicKeySpec = new RSAPublicKeySpec(rsaPrivateKey.getModulus(), rsaPrivateKey.getPrivateExponent());
            Key fakePublicKey = KeyFactory.getInstance("RSA").generatePublic(publicKeySpec);
            cipher = Cipher.getInstance("RSA");
            cipher.init(Cipher.ENCRYPT_MODE, fakePublicKey);
        }

        byte[] encryptedBytes = cipher.doFinal(plainText.getBytes("UTF-8"));
        String encryptedString = Base64.byteArrayToBase64(encryptedBytes);

        return encryptedString;
    }

    public static byte[][] genKeyPairBytes(int keySize)
            throws NoSuchAlgorithmException, NoSuchProviderException {
        byte[][] keyPairBytes = new byte[2][];

        KeyPairGenerator gen = KeyPairGenerator.getInstance("RSA", "SunRsaSign");
        gen.initialize(keySize, new SecureRandom());
        KeyPair pair = gen.generateKeyPair();

        keyPairBytes[0] = pair.getPrivate().getEncoded();
        keyPairBytes[1] = pair.getPublic().getEncoded();

        return keyPairBytes;
    }

    public static String[] genKeyPair(int keySize)
            throws NoSuchAlgorithmException, NoSuchProviderException {
        byte[][] keyPairBytes = genKeyPairBytes(keySize);
        String[] keyPairs = new String[2];

        keyPairs[0] = Base64.byteArrayToBase64(keyPairBytes[0]);
        keyPairs[1] = Base64.byteArrayToBase64(keyPairBytes[1]);

        return keyPairs;
    }


    public static void close(Closeable x) {
        if (x == null) {
            return;
        }

        try {
            x.close();
        } catch (Exception e) {
            //LOG.debug("close error", e);
            e.printStackTrace();
        }
    }

}

Base64 

/*
 * Copyright 1999-2018 Alibaba Group Holding Ltd.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package com.qbsea.rsa;

/**
 * Static methods for translating Base64 encoded strings to byte arrays and vice-versa.
 * 
 * @author Josh Bloch
 * @version %I%, %G%
 * @since 1.4
 */
public class Base64 {

    /**
     * Translates the specified byte array into a Base64 string as per Preferences.put(byte[]).
     */
    public static String byteArrayToBase64(byte[] a) {
        return byteArrayToBase64(a, false);
    }

    /**
     * Translates the specified byte array into an "alternate representation" Base64 string. This non-standard variant
     * uses an alphabet that does not contain the uppercase alphabetic characters, which makes it suitable for use in
     * situations where case-folding occurs.
     */
    public static String byteArrayToAltBase64(byte[] a) {
        return byteArrayToBase64(a, true);
    }

    private static String byteArrayToBase64(byte[] a, boolean alternate) {
        int aLen = a.length;
        int numFullGroups = aLen / 3;
        int numBytesInPartialGroup = aLen - 3 * numFullGroups;
        int resultLen = 4 * ((aLen + 2) / 3);
        StringBuilder result = new StringBuilder(resultLen);
        char[] intToAlpha = (alternate ? intToAltBase64 : intToBase64);

        // Translate all full groups from byte array elements to Base64
        int inCursor = 0;
        for (int i = 0; i < numFullGroups; i++) {
            int byte0 = a[inCursor++] & 0xff;
            int byte1 = a[inCursor++] & 0xff;
            int byte2 = a[inCursor++] & 0xff;
            result.append(intToAlpha[byte0 >> 2]);
            result.append(intToAlpha[(byte0 << 4) & 0x3f | (byte1 >> 4)]);
            result.append(intToAlpha[(byte1 << 2) & 0x3f | (byte2 >> 6)]);
            result.append(intToAlpha[byte2 & 0x3f]);
        }

        // Translate partial group if present
        if (numBytesInPartialGroup != 0) {
            int byte0 = a[inCursor++] & 0xff;
            result.append(intToAlpha[byte0 >> 2]);
            if (numBytesInPartialGroup == 1) {
                result.append(intToAlpha[(byte0 << 4) & 0x3f]);
                result.append("==");
            } else {
                // assert numBytesInPartialGroup == 2;
                int byte1 = a[inCursor++] & 0xff;
                result.append(intToAlpha[(byte0 << 4) & 0x3f | (byte1 >> 4)]);
                result.append(intToAlpha[(byte1 << 2) & 0x3f]);
                result.append('=');
            }
        }
        // assert inCursor == a.length;
        // assert result.length() == resultLen;
        return result.toString();
    }

    /**
     * This array is a lookup table that translates 6-bit positive integer index values into their "Base64 Alphabet"
     * equivalents as specified in Table 1 of RFC 2045.
     */
    private static final char intToBase64[]    = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M',
            'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
            'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2',
            '3', '4', '5', '6', '7', '8', '9', '+', '/' };

    /**
     * This array is a lookup table that translates 6-bit positive integer index values into their
     * "Alternate Base64 Alphabet" equivalents. This is NOT the real Base64 Alphabet as per in Table 1 of RFC 2045. This
     * alternate alphabet does not use the capital letters. It is designed for use in environments where "case folding"
     * occurs.
     */
    private static final char intToAltBase64[] = { '!', '"', '#', '$', '%', '&', '\'', '(', ')', ',', '-', '.', ':',
            ';', '<', '>', '@', '[', ']', '^', '`', '_', '{', '|', '}', '~', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h',
            'i', 'j', 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1', '2',
            '3', '4', '5', '6', '7', '8', '9', '+', '?' };

    /**
     * Translates the specified Base64 string (as per Preferences.get(byte[])) into a byte array.
     */
    public static byte[] base64ToByteArray(String s) {
        return base64ToByteArray(s, false);
    }

    /**
     * Translates the specified "alternate representation" Base64 string into a byte array.
     */
    public static byte[] altBase64ToByteArray(String s) {
        return base64ToByteArray(s, true);
    }

    private static byte[] base64ToByteArray(String s, boolean alternate) {
        byte[] alphaToInt = (alternate ? altBase64ToInt : base64ToInt);
        int sLen = s.length();
        int numGroups = sLen / 4;
        if (4 * numGroups != sLen) {
            throw new IllegalArgumentException("String length must be a multiple of four.");
        }
        int missingBytesInLastGroup = 0;
        int numFullGroups = numGroups;
        if (sLen != 0) {
            if (s.charAt(sLen - 1) == '=') {
                missingBytesInLastGroup++;
                numFullGroups--;
            }
            if (s.charAt(sLen - 2) == '=') {
                missingBytesInLastGroup++;
            }
        }
        byte[] result = new byte[3 * numGroups - missingBytesInLastGroup];

        // Translate all full groups from base64 to byte array elements
        int inCursor = 0, outCursor = 0;
        for (int i = 0; i < numFullGroups; i++) {
            int ch0 = base64toInt(s.charAt(inCursor++), alphaToInt);
            int ch1 = base64toInt(s.charAt(inCursor++), alphaToInt);
            int ch2 = base64toInt(s.charAt(inCursor++), alphaToInt);
            int ch3 = base64toInt(s.charAt(inCursor++), alphaToInt);
            result[outCursor++] = (byte) ((ch0 << 2) | (ch1 >> 4));
            result[outCursor++] = (byte) ((ch1 << 4) | (ch2 >> 2));
            result[outCursor++] = (byte) ((ch2 << 6) | ch3);
        }

        // Translate partial group, if present
        if (missingBytesInLastGroup != 0) {
            int ch0 = base64toInt(s.charAt(inCursor++), alphaToInt);
            int ch1 = base64toInt(s.charAt(inCursor++), alphaToInt);
            result[outCursor++] = (byte) ((ch0 << 2) | (ch1 >> 4));

            if (missingBytesInLastGroup == 1) {
                int ch2 = base64toInt(s.charAt(inCursor++), alphaToInt);
                result[outCursor++] = (byte) ((ch1 << 4) | (ch2 >> 2));
            }
        }
        // assert inCursor == s.length()-missingBytesInLastGroup;
        // assert outCursor == result.length;
        return result;
    }

    /**
     * Translates the specified character, which is assumed to be in the "Base 64 Alphabet" into its equivalent 6-bit
     * positive integer.
     * 
     * @throw IllegalArgumentException or ArrayOutOfBoundsException if c is not in the Base64 Alphabet.
     */
    private static int base64toInt(char c, byte[] alphaToInt) {
        int result = alphaToInt[c];
        if (result < 0) {
            throw new IllegalArgumentException("Illegal character " + c);
        }
        return result;
    }

    /**
     * This array is a lookup table that translates unicode characters drawn from the "Base64 Alphabet" (as specified in
     * Table 1 of RFC 2045) into their 6-bit positive integer equivalents. Characters that are not in the Base64
     * alphabet but fall within the bounds of the array are translated to -1.
     */
    private static final byte base64ToInt[]    = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62,
            -1, -1, -1, 63, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7,
            8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1, -1, 26, 27, 28,
            29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51 };

    /**
     * This array is the analogue of base64ToInt, but for the nonstandard variant that avoids the use of uppercase
     * alphabetic characters.
     */
    private static final byte altBase64ToInt[] = { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 0, 1, 2, 3, 4, 5, 6, 7, 8, -1, 62, 9, 10,
            11, -1, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 12, 13, 14, -1, 15, 63, 16, -1, -1, -1, -1, -1, -1, -1, -1,
            -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 17, -1, 18, 19, 21, 20, 26, 27, 28,
            29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 22, 23, 24, 25 };

}