java加密算法分享(rsa解密、对称加密、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！！");
        }

    }
}