使用MD5对数据库密码进行加密的实例
packagecom.lxitedu.tools.generate;
importjava.security.MessageDigest;
importjava.security.NoSuchAlgorithmException;
importcom.dcivision.framework.Crypt;
importcom.dcivision.framework.SystemParameterConstant;
importcom.dcivision.framework.SystemParameterFactory;
/**
*suitthephp
*
*@authorAdministrator
*
*/
publicclassMD5{
//解密类：Crypt
privatefinalstaticString[]hexDigits={"0","1","2","3","4","5","6","7","8","9","a","b","c","d",
"e","f"};
publicstaticvoidmain(String[]args)throwsException{
getMD5EncryptedString("");
StringencrptedPwd=Crypt.encrypt("diaoer",
SystemParameterFactory.getSystemParameter(SystemParameterConstant.CRYPTO_SALT));
System.out.println(getMD5EncryptedString("diaoer"));
System.out.println(encrptedPwd);
}
publicstaticStringgetMD5EncryptedString(StringsourceString)throwsNoSuchAlgorithmException{
//加密后的字符串
//创建具有指定算法名称的信息摘要
MessageDigestmd=MessageDigest.getInstance("MD5");
//使用指定的字节数组对摘要进行最后更新，然后完成摘要计算
byte[]results=md.digest(sourceString.getBytes());
returnbyteArrayToHexString(results);
}
privatestaticStringbyteArrayToHexString(byte[]b){
StringBufferresultSb=newStringBuffer();
for(inti=0;i<b.length;i++){
resultSb.append(byteToHexString(b[i]));
}
returnresultSb.toString();
}
/**
*将一个字节转化成十六进制形式的字符串
*/
privatestaticStringbyteToHexString(byteb){
intn=b;
if(n<0)
n=256+n;
intd1=n/16;
intd2=n%16;
returnhexDigits[d1]+hexDigits[d2];
}
}
解密：
/*
*@(#)Crypt.java
*
*Copyright(c)2003DCIVisionLtd
*Allrightsreserved.
*
*ThissoftwareistheconfidentialandproprietaryinformationofDCIVision
*Ltd("ConfidentialInformation").YoushallnotdisclosesuchConfidential
*Informationandshalluseitonlyinaccordancewiththetermsofthelicense
*agreementyouenteredintowithDCIVisionLtd.
*/
packagecom.dcivision.framework;
/**
*Crypt.java
*
*Thisclassistoprovideencryptanddecryptfunctionbyapasswordprovided.
*
*@authorRolloChan
*@companyDCIVisionLimited
*@creationdate25/06/2003
*@version$Revision:1.6$
*/
publicclassCrypt{
publicstaticfinalStringREVISION="$Revision:1.6$";
privateCrypt(){
}
/**
*encrypt
*
*Encryptastringwithapassword
*
*@parambuffer
*Thebuffertobeencrypted
*@parampassword
*Thepassword
*/
publicstaticStringencrypt(Stringbuffer,Stringpassword){
StringBuffersbSpace=newStringBuffer("");
buffer=sbSpace.toString()+buffer+sbSpace.toString();
char[]temp=newchar[buffer.length()];
inta=0;
for(inti=0;i<buffer.length();i++){
intb=password.charAt(a);
a++;
if(a>=password.length()){
a=0;
}
intc=(int)buffer.charAt(i);
temp[i]=(char)(c^b);
}
returntoHex(temp);
}
/**
*decrypt
*
*Decryptastringwithapassword
*
*@parambuffer
*Thebuffertobedecrypted
*@parampassword
*Thepassword
*/
publicstaticStringdecrypt(Stringbuffer,Stringpassword){
char[]temp=toChar(buffer);
Stringresult="";
inta=0;
for(inti=0;i<temp.length;i++){
intb=password.charAt(a);
a++;
if(a>=password.length()){
a=0;
}
intc=temp[i];
result+=(char)(c^b);//^按位异或XOR就是二个操作数只有一个是1的话结果就是1否则就是0。
}
returnresult.trim();
}
privatestaticinthexToInt(charc){
if(c>='0'&&c<='9'){
returnc-'0';
}
return(c-'a')+10;
}
privatestaticcharhexToChar(Stringbuffer){
intl=hexToInt(buffer.charAt(1));
inth=hexToInt(buffer.charAt(0));
return(char)(h*16+l);
}
privatestaticStringtoHex(char[]buffer){
Stringtemp="";
Stringresult="";
for(inti=0;i<buffer.length;i++){
intc=buffer[i];
temp=Integer.toHexString((int)c);
if(temp.length()==1){
temp="0"+temp;
}
result+=temp;
}
returnresult;
}
privatestaticchar[]toChar(Stringbuffer){
char[]result=newchar[buffer.length()/2];
for(inti=0;i<buffer.length();i+=2){
if(i+2<=buffer.length()){
Stringtemp=buffer.substring(i,i+2);
result[i/2]=(char)hexToChar(temp);
}
}
returnresult;
}
/**
*main
*
*@paramarg
*/
publicstaticvoidmain(Stringarg[]){
//Stringbuffer=arg[0];
//Stringpassword=arg[1];
Stringbuffer="diaoer";
Stringpassword="test";
Stringtemp=Crypt.encrypt(buffer,password);
System.out.println("buffer=\""+buffer+"\"");
System.out.println("password=\""+password+"\"");
System.out.println("encrypted=\""+temp+"\"");
System.out.println("decrypted=\""+Crypt.decrypt(temp,password)+"\"");
}
}