RSA签名,加解密处理核心文件

import java.io.ByteArrayOutputStream;

import java.io.UnsupportedEncodingException;

import java.security.InvalidKeyException;

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.Signature;

import java.security.SignatureException;

import java.security.cert.Certificate;

import java.security.interfaces.RSAPrivateKey;

import java.security.interfaces.RSAPublicKey;

import java.security.spec.PKCS8EncodedKeySpec;

import java.security.spec.X509EncodedKeySpec;

import java.util.HashMap;

import java.util.Map;

import javax.crypto.Cipher;

import org.apache.commons.codec.binary.Base64;

/**

 *

 * <p>RSA签名,加解密处理核心文件，注意：密钥长度1024</p>

 * @author leelun

 * @version $Id: RSA.java, v 0.1 2013-11-15 下午2:33:53 lilun Exp $

 */

public class RSA {

    /**

     * 签名算法

     */

    public static final String  SIGNATURE_ALGORITHM = "SHA1withRSA";

    /**

     * 加密算法RSA

     */

    public static final String  KEY_ALGORITHM       = "RSA";

    /**

     * 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;

    /**

     * 获取公钥的key

     */

    private static final String PUBLIC_KEY          = "RSAPublicKey";

    /**

     * 获取私钥的key

     */

    private static final String PRIVATE_KEY         = "RSAPrivateKey";

    /**

     * <p>

     * 生成密钥对(公钥和私钥)

     * </p>

     *

     * @return

     * @throws Exception

     */

    public static Map<String, Object> genKeyPair() throws Exception {

        KeyPairGenerator keyPairGen = KeyPairGenerator.getInstance(KEY_ALGORITHM);

        keyPairGen.initialize(1024);

        KeyPair keyPair = keyPairGen.generateKeyPair();

        RSAPublicKey publicKey = (RSAPublicKey) keyPair.getPublic();

        RSAPrivateKey privateKey = (RSAPrivateKey) keyPair.getPrivate();

        Map<String, Object> keyMap = new HashMap<String, Object>(2);

        keyMap.put(PUBLIC_KEY, publicKey);

        keyMap.put(PRIVATE_KEY, privateKey);

        return keyMap;

    }

    public static void main(String[] args) throws Exception {

        Map<String, Object> genKeyPair = genKeyPair();

        String base64publicKey = getPublicKey(genKeyPair);

        System.out.println("公钥 " + base64publicKey);

        String base64privateKey = getPrivateKey(genKeyPair);

        System.out.println("私钥 " + base64privateKey);

        String passwd = "cat123113";

        String charsetName = "utf-8";

        String encryptByPublicKey = Base64.encodeBase64String((encryptByPublicKey(

            passwd.getBytes(charsetName), base64publicKey)));

        System.out.println("加密 " + encryptByPublicKey);

        byte[] decryptByPrivateKey = decryptByPrivateKey(Base64.decodeBase64(encryptByPublicKey),

            base64privateKey);

        String string = new String(decryptByPrivateKey, "utf-8");

        System.out.println("解密后 " + string);

    }

    /**

     * 签名字符串

     *

     * @param text

     *            需要签名的字符串

     * @param privateKey 私钥(BASE64编码)

     *

     * @param charset

     *            编码格式

     * @return 签名结果(BASE64编码)

     */

    public static String sign(String text, String privateKey, String charset) throws Exception {

        byte[] keyBytes = Base64.decodeBase64(privateKey);

        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

        PrivateKey privateK = keyFactory.generatePrivate(pkcs8KeySpec);

        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);

        signature.initSign(privateK);

        signature.update(getContentBytes(text, charset));

        byte[] result = signature.sign();

        return Base64.encodeBase64String(result);

    }

    public static String sign(String text, PrivateKey privateKey, String charset)

                                                                                 throws SignatureException,

                                                                                 InvalidKeyException {

        try {

            Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);

            signature.initSign(privateKey);

            signature.update(getContentBytes(text, charset));

            byte[] result = signature.sign();

            return Base64.encodeBase64String(result);

        } catch (NoSuchAlgorithmException e) {

            //不可能发生，

            return null;

        }

    }

    /**

     * 签名字符串

     *

     * @param text

     *            需要签名的字符串

     * @param sign

     *            客户签名结果

     * @param publicKey

     *            公钥(BASE64编码)

     * @param charset

     *            编码格式

     * @return 验签结果

     */

    public static boolean verify(String text, String sign, String publicKey, String charset)

                                                                                            throws Exception {

        byte[] keyBytes = Base64.decodeBase64(publicKey);

        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

        PublicKey publicK = keyFactory.generatePublic(keySpec);

        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);

        signature.initVerify(publicK);

        signature.update(getContentBytes(text, charset));

        return signature.verify(Base64.decodeBase64(sign));

    }

    /**

     * <P>

     * 私钥解密

     * </p>

     *

     * @param encryptedData 已加密数据

     * @param privateKey 私钥(BASE64编码)

     * @return

     * @throws Exception

     */

    public static byte[] decryptByPrivateKey(byte[] encryptedData, String privateKey)

                                                                                     throws Exception {

        byte[] keyBytes = Base64.decodeBase64(privateKey);

        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);

        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

        cipher.init(Cipher.DECRYPT_MODE, privateK);

        int inputLen = encryptedData.length;

        ByteArrayOutputStream out = new ByteArrayOutputStream();

        int offSet = 0;

        byte[] cache;

        int i = 0;

        // 对数据分段解密

        while (inputLen - offSet > 0) {

            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {

                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);

            } else {

                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);

            }

            out.write(cache, 0, cache.length);

            i++;

            offSet = i * MAX_DECRYPT_BLOCK;

        }

        byte[] decryptedData = out.toByteArray();

        out.close();

        return decryptedData;

    }

    /**

     * <p>

     * 公钥解密

     * </p>

     *

     * @param encryptedData 已加密数据

     * @param publicKey 公钥(BASE64编码)

     * @return

     * @throws Exception

     */

    public static byte[] decryptByPublicKey(byte[] encryptedData, String publicKey)

                                                                                   throws Exception {

        byte[] keyBytes = Base64.decodeBase64(publicKey);

        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

        Key publicK = keyFactory.generatePublic(x509KeySpec);

        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

        cipher.init(Cipher.DECRYPT_MODE, publicK);

        int inputLen = encryptedData.length;

        ByteArrayOutputStream out = new ByteArrayOutputStream();

        int offSet = 0;

        byte[] cache;

        int i = 0;

        // 对数据分段解密

        while (inputLen - offSet > 0) {

            if (inputLen - offSet > MAX_DECRYPT_BLOCK) {

                cache = cipher.doFinal(encryptedData, offSet, MAX_DECRYPT_BLOCK);

            } else {

                cache = cipher.doFinal(encryptedData, offSet, inputLen - offSet);

            }

            out.write(cache, 0, cache.length);

            i++;

            offSet = i * MAX_DECRYPT_BLOCK;

        }

        byte[] decryptedData = out.toByteArray();

        out.close();

        return decryptedData;

    }

    /**

     * <p>

     * 公钥加密

     * </p>

     *

     * @param data 源数据

     * @param publicKey 公钥(BASE64编码)

     * @return

     * @throws Exception

     */

    public static byte[] encryptByPublicKey(byte[] data, String publicKey) throws Exception {

        byte[] keyBytes = Base64.decodeBase64(publicKey);

        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

        Key publicK = keyFactory.generatePublic(x509KeySpec);

        // 对数据加密

        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

        cipher.init(Cipher.ENCRYPT_MODE, publicK);

        int inputLen = data.length;

        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 > MAX_ENCRYPT_BLOCK) {

                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);

            } else {

                cache = cipher.doFinal(data, offSet, inputLen - offSet);

            }

            out.write(cache, 0, cache.length);

            i++;

            offSet = i * MAX_ENCRYPT_BLOCK;

        }

        byte[] encryptedData = out.toByteArray();

        out.close();

        return encryptedData;

    }

    /**

     * <p>

     * 公钥加密

     * </p>

     *

     * @param data 源数据

     * @param cert 证书

     * @return

     * @throws Exception

     */

    public static byte[] encryptByPublicKey(byte[] data, Certificate cert) throws Exception {

        // 对数据加密

        PublicKey uk = cert.getPublicKey();

        Cipher cipher = Cipher.getInstance(uk.getAlgorithm());

        cipher.init(Cipher.ENCRYPT_MODE, uk);

        int inputLen = data.length;

        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 > MAX_ENCRYPT_BLOCK) {

                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);

            } else {

                cache = cipher.doFinal(data, offSet, inputLen - offSet);

            }

            out.write(cache, 0, cache.length);

            i++;

            offSet = i * MAX_ENCRYPT_BLOCK;

        }

        byte[] encryptedData = out.toByteArray();

        out.close();

        return encryptedData;

    }

    /**

     * <p>

     * 私钥加密

     * </p>

     *

     * @param data 源数据

     * @param privateKey 私钥(BASE64编码)

     * @return

     * @throws Exception

     */

    public static byte[] encryptByPrivateKey(byte[] data, String privateKey) throws Exception {

        byte[] keyBytes = Base64.decodeBase64(privateKey);

        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);

        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);

        Key privateK = keyFactory.generatePrivate(pkcs8KeySpec);

        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());

        cipher.init(Cipher.ENCRYPT_MODE, privateK);

        int inputLen = data.length;

        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 > MAX_ENCRYPT_BLOCK) {

                cache = cipher.doFinal(data, offSet, MAX_ENCRYPT_BLOCK);

            } else {

                cache = cipher.doFinal(data, offSet, inputLen - offSet);

            }

            out.write(cache, 0, cache.length);

            i++;

            offSet = i * MAX_ENCRYPT_BLOCK;

        }

        byte[] encryptedData = out.toByteArray();

        out.close();

        return encryptedData;

    }

    /**

     * @param content

     * @param charset

     * @return

     * @throws SignatureException

     * @throws UnsupportedEncodingException

     */

    private static byte[] getContentBytes(String content, String charset) {

        if (charset == null || "".equals(charset)) {

            return content.getBytes();

        }

        try {

            return content.getBytes(charset);

        } catch (UnsupportedEncodingException e) {

            throw new RuntimeException("签名过程中出现错误,指定的编码集不对,您目前指定的编码集是:" + charset);

        }

    }

    /**

     * <p>

     * 获取私钥

     * </p>

     *

     * @param keyMap 密钥对

     * @return

     * @throws Exception

     */

    public static String getPrivateKey(Map<String, Object> keyMap) throws Exception {

        Key key = (Key) keyMap.get(PRIVATE_KEY);

        return Base64.encodeBase64String(key.getEncoded());

    }

    /**

     * <p>

     * 获取公钥

     * </p>

     *

     * @param keyMap 密钥对

     * @return

     * @throws Exception

     */

    public static String getPublicKey(Map<String, Object> keyMap) throws Exception {

        Key key = (Key) keyMap.get(PUBLIC_KEY);

        return Base64.encodeBase64String(key.getEncoded());

    }

}