这次给大家带来如何使用java 3des加解密，使用java 3des加解密的注意事项有哪些，下面就是实战案例，一起来看一下。
<pre name="code" class="java">java写的加密解密算法及调用范例
1、.java算法范例
package common.jutility;
import javax.crypto.*;
import javax.crypto.spec.secretkeyspec;
import com.sun.org.apache.xerces.internal.impl.dv.util.base64;
public class encryptutils {
/// <summary>
/// 3des解码
/// </summary>
/// <param name="value">待解密字符串</param>
/// <param name="key">原始密钥字符串</param>
/// <returns></returns>
public static string decrypt3des(string value, string key) throws exception {
byte[] b = decryptmode(getkeybytes(key), base64.decode(value));
return new string(b);
}
/// <summary>
/// 3des加密
/// </summary>
/// <param name="value">待加密字符串</param>
/// <param name="strkey">原始密钥字符串</param>
/// <returns></returns>
public static string encrypt3des(string value, string key) throws exception {
string str = byte2base64(encryptmode(getkeybytes(key), value.getbytes()));
return str;
}
//计算24位长的密码byte值,首先对原始密钥做md5算hash值，再用前8位数据对应补全后8位
public static byte[] getkeybytes(string strkey) throws exception {
if (null == strkey || strkey.length() < 1)
throw new exception("key is null or empty!");
java.security.messagedigest alg = java.security.messagedigest.getinstance("md5");
alg.update(strkey.getbytes());
byte[] bkey = alg.digest();
system.out.println("md5key.length=" + bkey.length);
system.out.println("md5key=" + byte2hex(bkey));
int start = bkey.length;
byte[] bkey24 = new byte[24];
for (int i = 0; i < start; i++) {
bkey24[i] = bkey[i];
}
for (int i = start; i < 24; i++) {//为了与.net16位key兼容
bkey24[i] = bkey[i - start];
}
system.out.println("byte24key.length=" + bkey24.length);
system.out.println("byte24key=" + byte2hex(bkey24));
return bkey24;
}
private static final string algorithm = "desede"; //定义 加密算法,可用 des,desede,blowfish
//keybyte为加密密钥，长度为24字节
//src为被加密的数据缓冲区（源）
public static byte[] encryptmode(byte[] keybyte, byte[] src) {
try {
//生成密钥
secretkey deskey = new secretkeyspec(keybyte, algorithm); //加密
cipher c1 = cipher.getinstance(algorithm);
c1.init(cipher.encrypt_mode, deskey);
return c1.dofinal(src);
} catch (java.security.nosuchalgorithmexception e1) {
e1.printstacktrace();
} catch (javax.crypto.nosuchpaddingexception e2) {
e2.printstacktrace();
} catch (java.lang.exception e3) {
e3.printstacktrace();
}
return null;
}
//keybyte为加密密钥，长度为24字节
//src为加密后的缓冲区
public static byte[] decryptmode(byte[] keybyte, byte[] src) {
try { //生成密钥
secretkey deskey = new secretkeyspec(keybyte, algorithm);
//解密
cipher c1 = cipher.getinstance(algorithm);
c1.init(cipher.decrypt_mode, deskey);
return c1.dofinal(src);
} catch (java.security.nosuchalgorithmexception e1) {
e1.printstacktrace();
} catch (javax.crypto.nosuchpaddingexception e2) {
e2.printstacktrace();
} catch (java.lang.exception e3) {
e3.printstacktrace();
}
return null;
}
//转换成base64编码
public static string byte2base64(byte[] b) {
return base64.encode(b);
}
//转换成十六进制字符串
public static string byte2hex(byte[] b) {
string hs = "";
string stmp = "";
for (int n = 0; n < b.length; n++) {
stmp = (java.lang.integer.tohexstring(b[n] & 0xff));
if (stmp.length() == 1)
hs = hs + "0" + stmp;
else
hs = hs + stmp;
if (n < b.length - 1)
hs = hs + ":";
}
return hs.touppercase();
}
}
2、java 算法调用范例
package test.com;
import com.sun.org.apache.xerces.internal.impl.dv.util.base64;
import common.jutility.encryptutils;//用原始密钥经md5转换和补位后的新密钥来做3des加密解密
public class test3des {
public static void main(string[] args) {
string key = "abcd1234";
string password = "password";
system.out.println("key=" + key + ",password=" + password);
system.out.println();
system.out.println("----------示例开始：使用java写的算法加密解密-----------");
try {
string encrypt = "";
string decrypt = "";
byte[] bkey = encryptutils.getkeybytes(key);
encrypt = encryptutils.byte2base64(encryptutils.encryptmode(bkey, password.getbytes()));
system.out.println("用预转换密钥算加密结果=" + encrypt);
system.out.println("加密后base64表示=" + encryptutils.byte2hex(base64.decode(encrypt)));
system.out.println("调用原始密钥算加密结果=" + encryptutils.encrypt3des(password, key));
try {
decrypt = new string(encryptutils.decryptmode(bkey, base64.decode(encrypt)));
system.out.println("用预转换密钥算解密结果=" + decrypt);
system.out.println("调用原始密钥算解密结果=" + encryptutils.decrypt3des(encrypt, key));
} catch (exception ex) {
system.out.println("exception:" + ex.getmessage());
}
} catch (exception ex) {
system.out.println("exception:" + ex.getmessage());
}
system.out.println("----------示例结束：使用java写的算法加密解密-----------");
}
}
3、(7)的运算结果
key=abcd1234,password=password
----------示例开始：使用java写的算法加密解密-----------
md5key.length=16
md5key=e1:9d:5c:d5:af:03:78:da:05:f6:3f:89:1c:74:67:af
byte24key.length=24
byte24key=e1:9d:5c:d5:af:03:78:da:05:f6:3f:89:1c:74:67:af:e1:9d:5c:d5:af:03:78:da
用预转换密钥算加密结果=ftwpzxfh4wpzt4orq8uslq==
加密后base64表示=7e:dc:0f:cf:11:47:e1:6a:73:4f:83:ab:ab:cb:92:2d
md5key.length=16
md5key=e1:9d:5c:d5:af:03:78:da:05:f6:3f:89:1c:74:67:af
byte24key.length=24
byte24key=e1:9d:5c:d5:af:03:78:da:05:f6:3f:89:1c:74:67:af:e1:9d:5c:d5:af:03:78:da
调用原始密钥算加密结果=ftwpzxfh4wpzt4orq8uslq==
用预转换密钥算解密结果=password
md5key.length=16
md5key=e1:9d:5c:d5:af:03:78:da:05:f6:3f:89:1c:74:67:af
byte24key.length=24
byte24key=e1:9d:5c:d5:af:03:78:da:05:f6:3f:89:1c:74:67:af:e1:9d:5c:d5:af:03:78:da
调用原始密钥算解密结果=password
----------示例结束：使用java写的算法加密解密-----------
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