java加密演算法分享(rsa解密、對稱加密、md5加密)

import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.PrivateKey;
import java.security.PublicKey;
import java.security.SecureRandom;
import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.KeyGenerator;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.SecretKey;
import com.sun.mail.util.BASE64DecoderStream;
import com.sun.mail.util.BASE64EncoderStream;

public class util {
    /**
     * 传入名文和公钥钥对数据进行RSA解密
     * <br>返回值：String
     * <br>@param src
     * <br>@param pubkey
     * <br>@return
     */
    public static String rsaEncoding(String src,PublicKey pubkey){
        try {
            Cipher cip = Cipher.getInstance("RSA");
            cip.init(cip.ENCRYPT_MODE, pubkey);
            byte[] by = cip.doFinal(src.getBytes());
            return new String(BASE64EncoderStream.encode(by));

        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        } catch (NoSuchPaddingException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
            throw new RuntimeException(e);
        } catch (BadPaddingException e) {
            throw new RuntimeException(e);
        }

    }
    /**
     * 传入RSA密文和私钥对数据进行解密
     * <br>返回值：String
     * <br>@param sec
     * <br>@param privkey
     * <br>@return
     */
    public static String rsaDeEncoding(String sec,PrivateKey privkey){
        try {
            Cipher cip = Cipher.getInstance("RSA");
            cip.init(cip.DECRYPT_MODE, privkey);
            byte[] by = BASE64DecoderStream.decode(sec.getBytes());
            return new String(cip.doFinal(by));

        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        } catch (NoSuchPaddingException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
            throw new RuntimeException(e);
        } catch (BadPaddingException e) {
            throw new RuntimeException(e);
        }

    }

    /**
     * 传入字符串、密钥，并加密字符串（对称加密加密），支持：DES、AES、DESede(3DES)
     * <br>返回值：String 密文
     * <br>@param src
     * <br>@param key
     * <br>@param method(DES、AES、DESede)
     * <br>@return
     */
    //对称加密加密
    public static String doubKeyEncoding(String src,String keysrc,String method) {
        SecretKey key;
        try {
            //生成密钥
            KeyGenerator kg =  KeyGenerator.getInstance(method);
            //初始化此密钥生成器。
            kg.init(new SecureRandom(keysrc.getBytes("utf-8")));
            key = kg.generateKey();

            //加密
            Cipher ciph =  Cipher.getInstance(method);
            ciph.init(Cipher.ENCRYPT_MODE, key);
            ciph.update(src.getBytes("utf-8"));
            //使用64进行编码，一避免出现丢数据情景
            byte[] by = BASE64EncoderStream.encode(ciph.doFinal());
            return new String(by);
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        } catch (NoSuchPaddingException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
            throw new RuntimeException(e);
        } catch (BadPaddingException e) {
            throw new RuntimeException(e);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }
    /**
     * 传入字符串、密钥、加密方式，并解密字符串（对称加密解密密），支持：DES、AES、DESede(3DES)
     * <br>生成时间：2014年5月2日  下午1:12:13
     * <br>返回值：String 密钥原文
     * <br>@param sec
     * <br>@param key
     * <br>@param method(DES、AES、DESede)
     * <br>@return
     */
    public static String doubKeyDencoding(String sec,String keysrc,String method) {
        SecretKey key;
        try {
            //生成密钥
            KeyGenerator kg =  KeyGenerator.getInstance(method);
            //初始化此密钥生成器。
            kg.init(new SecureRandom(keysrc.getBytes("utf-8")));
            key = kg.generateKey();
            //加密
            Cipher ciph =  Cipher.getInstance(method);
            ciph.init(ciph.DECRYPT_MODE, key);
            //使用64进行解码，一避免出现丢数据情景
            byte[] by = BASE64DecoderStream.decode(sec.getBytes());
            ciph.update(by);
            return new String(ciph.doFinal());

        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e);
        } catch (NoSuchPaddingException e) {
            throw new RuntimeException(e);
        } catch (InvalidKeyException e) {
            throw new RuntimeException(e);
        } catch (IllegalBlockSizeException e) {
            throw new RuntimeException(e);
        } catch (BadPaddingException e) {
            throw new RuntimeException(e);
        } catch (UnsupportedEncodingException e) {
            throw new RuntimeException(e);
        }
    }

    /**
     * 单向信息加密(信息摘要)，支持：md5、md2、SHA(SHA-1，SHA1)、SHA-256、SHA-384、SHA-512,
     * <br>返回值：String         加密后的密文
     * <br>@param src     传入加密字符串(明文)
     * <br>@param method  指定算法(md5、md2、SHA(SHA-1，SHA1)、SHA-256、SHA-384、SHA-512)
     * <br>@return
     */
    public static String ecodingPasswd(String src,String method){

        try {
            //信息摘要算法
            MessageDigest md5 = MessageDigest.getInstance(method);
            md5.update(src.getBytes());
            byte[] encoding = md5.digest();
            //使用64进行编码，一避免出现丢数据情景
            return new String(BASE64EncoderStream.encode(encoding));
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException(e+"加密失败！！");
        }

    }
}

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