第php實(shí)現(xiàn)的rc4加密解密類定義與用法示例本文實(shí)例講述了php實(shí)現(xiàn)的rc4加密解密類。分享給大家供大家參考，具體如下：

class.rc4crypt.php文件：

*By

define('CRYPT_RC4_MODE_INTERNAL',1);

define('CRYPT_RC4_MODE_MCRYPT',2);

define('CRYPT_RC4_ENCRYPT',0);

define('CRYPT_RC4_DECRYPT',1);

classCrypt_RC4{

*TheKey

*@seeCrypt_RC4::setKey()

*@varString

*@accessprivate

var$key="\0";

*TheKeyStreamforencryption

*IfCRYPT_RC4_MODE==CRYPT_RC4_MODE_MCRYPT,thiswillbeequaltothemcryptobject

*@seeCrypt_RC4::setKey()

*@varArray

*@accessprivate

var$encryptStream=false;

*TheKeyStreamfordecryption

*IfCRYPT_RC4_MODE==CRYPT_RC4_MODE_MCRYPT,thiswillbeequaltothemcryptobject

*@seeCrypt_RC4::setKey()

*@varArray

*@accessprivate

var$decryptStream=false;

*The$iand$jindexesforencryption

*@seeCrypt_RC4::_crypt()

*@varInteger

*@accessprivate

var$encryptIndex=0;

*The$iand$jindexesfordecryption

*@seeCrypt_RC4::_crypt()

*@varInteger

*@accessprivate

var$decryptIndex=0;

*MCryptparameters

*@seeCrypt_RC4::setMCrypt()

*@varArray

*@accessprivate

var$mcrypt=array('','');

*TheEncryptionAlgorithm

*OnlyusedifCRYPT_RC4_MODE==CRYPT_RC4_MODE_MCRYPT.OnlypossiblevaluesareMCRYPT_RC4orMCRYPT_ARCFOUR.

*@seeCrypt_RC4::Crypt_RC4()

*@varInteger

*@accessprivate

var$mode;

*DefaultConstructor.

*Determineswhetherornotthemcryptextensionshouldbeused.

*@paramoptionalInteger$mode

*@returnCrypt_RC4

*@accesspublic

var$continuousBuffer;

functionCrypt_RC4()

if(!defined('CRYPT_RC4_MODE')){

switch(true){

caseextension_loaded('mcrypt')(defined('MCRYPT_ARCFOUR')||defined('MCRYPT_RC4')):

//i'dchecktoseeifrc4wassupported,bydoingin_array('arcfour',mcrypt_list_algorithms('')),

//butsincethatcanbechangedaftertheobjecthasbeencreated,theredoesn'tseemtobe

//alotofpoint...

define('CRYPT_RC4_MODE',CRYPT_RC4_MODE_MCRYPT);

break;

default:

define('CRYPT_RC4_MODE',CRYPT_RC4_MODE_INTERNAL);

switch(CRYPT_RC4_MODE){

caseCRYPT_RC4_MODE_MCRYPT:

switch(true){

casedefined('MCRYPT_ARCFOUR'):

$this-mode=MCRYPT_ARCFOUR;

break;

casedefined('MCRYPT_RC4');

$this-mode=MCRYPT_RC4;

*Setsthekey.

*Keyscanbebetween1and256byteslong.Iftheyarelongerthen256bytes,thefirst256byteswill

*beused.Ifnokeyisexplicitlyset,it'llbeassumedtobeasinglenullbyte.

*@accesspublic

*@paramString$key

functionsetKey($key)

$this-key=$key;

if(CRYPT_RC4_MODE==CRYPT_RC4_MODE_MCRYPT){

return;

$keyLength=strlen($key);

$keyStream=array();

for($i=0;$i256;$i++){

$keyStream[$i]=$i;

$j=0;

for($i=0;$i256;$i++){

$j=($j+$keyStream[$i]+ord($key[$i%$keyLength]))255;

$temp=$keyStream[$i];

$keyStream[$i]=$keyStream[$j];

$keyStream[$j]=$temp;

$this-encryptIndex=$this-decryptIndex=array(0,0);

$this-encryptStream=$this-decryptStream=$keyStream;

*Dummyfunction.

*Someprotocols,suchasWEP,prependan"initializationvector"tothekey,effectivelycreatinganewkey[1].

*Ifyouneedtouseaninitializationvectorinthismanner,feelfreetoprependittothekey,yourself,before

*callingsetKey().

*[1]WEP'sinitializationvectors(IV's)areusedinasomewhatinsecureway.Since,inthatprotocol,

*theIV'sarerelativelyeasytopredict,anattackdescribedby

*{@link/~aboba/IEEE/rc4_ksaproc.pdfScottFluhrer,ItsikMantin,andAdiShamir}

*canbeusedtoquicklyguessattherestofthekey.Thefollowinglinkselaborate:

*{@link/rsalabs/node.aspid=2009/rsalabs/node.aspid=2009}

*{@link/wiki/Related_key_attack/wiki/Related_key_attack}

*@paramString$iv

*@seeCrypt_RC4::setKey()

*@accesspublic

functionsetIV($iv)

*SetsMCryptparameters.(optional)

*IfMCryptisbeingused,emptystringswillbeused,unlessotherwisespecified.

*@link/function.mcrypt-module-open#function.mcrypt-module-open

*@accesspublic

*@paramoptionalInteger$algorithm_directory

*@paramoptionalInteger$mode_directory

functionsetMCrypt($algorithm_directory='',$mode_directory='')

if(CRYPT_RC4_MODE==CRYPT_RC4_MODE_MCRYPT){

$this-mcrypt=array($algorithm_directory,$mode_directory);

$this-_closeMCrypt();

*Encryptsamessage.

*@seeCrypt_RC4::_crypt()

*@accesspublic

*@paramString$plaintext

functionencrypt($plaintext)

returnself::toHex($this-_crypt($plaintext,CRYPT_RC4_ENCRYPT));

*Decryptsamessage.

*$this-decrypt($this-encrypt($plaintext))==$this-encrypt($this-encrypt($plaintext)).

*Atleastifthecontinuousbufferisdisabled.

*@seeCrypt_RC4::_crypt()

*@accesspublic

*@paramString$ciphertext

functiondecrypt($ciphertext)

$ciphertext=self::fromHex($ciphertext);

return$this-_crypt($ciphertext,CRYPT_RC4_DECRYPT);

*Encryptsordecryptsamessage.

*@seeCrypt_RC4::encrypt()

*@seeCrypt_RC4::decrypt()

*@accessprivate

*@paramString$text

*@paramInteger$mode

function_crypt($text,$mode)

if(CRYPT_RC4_MODE==CRYPT_RC4_MODE_MCRYPT){

$keyStream=$mode==CRYPT_RC4_ENCRYPT'encryptStream':'decryptStream';

if($this-$keyStream===false){

$this-$keyStream=mcrypt_module_open($this-mode,$this-mcrypt[0],MCRYPT_MODE_STREAM,$this-mcrypt[1]);

mcrypt_generic_init($this-$keyStream,$this-key,'');

}elseif(!$this-continuousBuffer){

mcrypt_generic_init($this-$keyStream,$this-key,'');

$newText=mcrypt_generic($this-$keyStream,$text);

if(!$this-continuousBuffer){

mcrypt_generic_deinit($this-$keyStream);

return$newText;

if($this-encryptStream===false){

$this-setKey($this-key);

switch($mode){

caseCRYPT_RC4_ENCRYPT:

$keyStream=$this-encryptStream;

list($i,$j)=$this-encryptIndex;

break;

caseCRYPT_RC4_DECRYPT:

$keyStream=$this-decryptStream;

list($i,$j)=$this-decryptIndex;

$newText='';

for($k=0;$kstrlen($text);$k++){

$i=($i+1)255;

$j=($j+$keyStream[$i])255;

$temp=$keyStream[$i];

$keyStream[$i]=$keyStream[$j];

$keyStream[$j]=$temp;

$temp=$keyStream[($keyStream[$i]+$keyStream[$j])255];

$newText.=chr(ord($text[$k])^$temp);

if($this-continuousBuffer){

switch($mode){

caseCRYPT_RC4_ENCRYPT:

$this-encryptStream=$keyStream;

$this-encryptIndex=array($i,$j);

break;

caseCRYPT_RC4_DECRYPT:

$this-decryptStream=$keyStream;

$this-decryptIndex=array($i,$j);

return$newText;

*Treatconsecutive"packets"asiftheyareacontinuousbuffer.

*Sayyouhavea16-byteplaintext$plaintext.Usingthedefaultbehavior,thetwofollowingcodesnippets

*willyielddifferentoutputs:

*code

*echo$rc4-encrypt(substr($plaintext,0,8));

*echo$rc4-encrypt(substr($plaintext,8,8));

*/code

*code

*echo$rc4-encrypt($plaintext);

*/code

*Thesolutionistoenablethecontinuousbuffer.Althoughthiswillresolvetheabovediscrepancy,itcreates

*another,asdemonstratedwiththefollowing:

*code

*$rc4-encrypt(substr($plaintext,0,8));

*echo$rc4-decrypt($des-encrypt(substr($plaintext,8,8)));

*/code

*code

*echo$rc4-decrypt($des-encrypt(substr($plaintext,8,8)));

*/code

*Withthecontinuousbufferdisabled,thesewouldyieldthesameoutput.Withitenabled,theyyielddifferent

*outputs.Thereasonisduetothefactthattheinitializationvector'schangeaftereveryencryption/

*decryptionroundwhenthecontinuousbufferisenabled.Whenit'sdisabled,theyremainconstant.

*Putanotherway,whenthecontinuousbufferisenabled,thestateoftheCrypt_DES()objectchangesaftereach

*encryption/decryptionround,whereasotherwise,it'dremainconstant.Forthisreason,it'srecommendedthat

*continuousbuffersnotbeused.Theydoofferbettersecurityandare,infact,sometimesrequired(SSHusesthem),

*however,theyarealsolessintuitiveandmorelikelytocauseyouproblems.

*@seeCrypt_RC4::disableContinuousBuffer()

*@accesspublic

functionenableContinuousBuffer()

$this-continuousBuffer=true;

*Treatconsecutivepacketsasiftheyareadiscontinuousbuffer.

*Thedefaultbehavior.

*@seeCrypt_RC4::enableContinuousBuffer()

*@accesspublic

functiondisableContinuousBuffer()

if(CRYPT_RC4_MODE==CRYPT_RC4_MODE_INTERNAL){

$this-encryptIndex=$this-decryptIndex=array(0,0);

$this-setKey($this-key);

$this-continuousBuffer=false;

*Dummyfunction.

*SinceRC4isastreamcipherandnotablockcipher,nopaddingisnecessary.Theonlyreasonthisfunctionis

*includedissothatyoucanswitchbetweenablockcipherandastreamciphertransparently.

*@seeCrypt_RC4::disablePadding()

*@accesspublic

functionenablePadding()

*Dummyfunction.

*@seeCrypt_RC4::enablePadding()

*@accesspublic

functiondisablePadding()

*Classdestructor.

*Willbecalled,automatically,ifyou'reusingPHP5.Ifyou'reusingPHP4,callityourself.Onlyreally

*needstobecalledifmcryptisbeingused.

*@accesspublic

function__destruct()

if(CRYPT_RC4_MODE==CRYPT_RC4_MODE_MCRYPT){

$this-_closeMCrypt();

*ProperlyclosetheMCryptobjects.

*@accessprviate

function_closeMCrypt()

if($this-encryptStream!==false){

if($this-continuousBuffer){

mcrypt_generic_deinit($this-encryptStream);

mcrypt_module_close($this-encryptStream);

$this-encryptStream=false;

if($this-decryptStream!==false){

if($this-continuousBuffer){

mcrypt_generic_deinit($this-decryptStream);

mcrypt_module_close($this-decryptStream);

$this-decryptStream=false;

//@functionfromHex把十六進(jìn)制數(shù)轉(zhuǎn)換成字符串

functiontoHex($sa,$len=0){

$buf="";

if($len==0)