<html>
<head>
<title>aes demo</title>
</head>
<body>
<script type="text/javascript" src="./CryptoJS/aes.js"></script>
<script type="text/javascript" src="./CryptoJS/pad-zeropadding.js"></script>
<script type="text/javascript">
text = 'did=12345dg&version=1'
var key = '123454536f667445454d537973576562'
key = CryptoJS.enc.Utf8.parse(key)
var iv = "1234577290ABCDEF1264147890ACAE45"
iv = CryptoJS.enc.Utf8.parse(iv)
var encrypted = CryptoJS.AES.encrypt(text, key, {
iv: iv,
mode: CryptoJS.mode.CBC,
padding: CryptoJS.pad.ZeroPadding
}).toString()
document.write(encrypted)
</script>
</body>
</html>
后端
public function encrypt2($input = ''){
$pk = "123454536f667445454d537973576562"
$iv = substr("1234577290ABCDEF1264147890ACAE45", 0, 16)
// $t = 'T10515'
$encrypted = ( mcrypt_encrypt(MCRYPT_RIJNDAEL_128, $pk, $input, MCRYPT_MODE_CBC,$iv) )
return base64_encode($encrypted)
}
public function decrypt2($encrypted){
$pk = "123454536f667445454d537973576562"
$iv = substr("1234577290ABCDEF1264147890ACAE45", 0, 16)
// $t = 'T10515'
// $encrypted = "b7y/JPJFNTfxNVR8H4NNtw=="
return mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $pk, base64_decode($encrypted), MCRYPT_MODE_CBC, $iv)
}
可以推断， js 部分实际只使用了 iv 的 16 位长度
ps：
js加密后默认会base64_encode
使用php解密需要base64_decode后才一致
所以使用js加密和php解密时候需要注意，php端要先base64_decode再解密，例：
js加密的串是$t=b7y/JPJFNTfxNVR8H4NNtw==
php需要
$password= trim(mcrypt_decrypt(MCRYPT_RIJNDAEL_128, $pk,base64_decode( $t), MCRYPT_MODE_CBC, $iv))
则$password才能正确解析出来
需要引入的两个js文件
ase.js
[javascript] view plain copy
/*
CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
var CryptoJS=CryptoJS||function(u,p){var d={},l=d.lib={},s=function(){},t=l.Base={extend:function(a){s.prototype=thisvar c=new sa&&c.mixIn(a)c.hasOwnProperty("init")||(c.init=function(){c.$super.init.apply(this,arguments)})c.init.prototype=cc.$super=thisreturn c},create:function(){var a=this.extend()a.init.apply(a,arguments)return a},init:function(){},mixIn:function(a){for(var c in a)a.hasOwnProperty(c)&&(this[c]=a[c])a.hasOwnProperty("toString")&&(this.toString=a.toString)},clone:function(){return this.init.prototype.extend(this)}},
r=l.WordArray=t.extend({init:function(a,c){a=this.words=a||[]this.sigBytes=c!=p?c:4*a.length},toString:function(a){return(a||v).stringify(this)},concat:function(a){var c=this.words,e=a.words,j=this.sigBytesa=a.sigBytesthis.clamp()if(j%4)for(var k=0k<ak++)c[j+k>>>2]|=(e[k>>>2]>>>24-8*(k%4)&255)<<24-8*((j+k)%4)else if(65535<e.length)for(k=0k<ak+=4)c[j+k>>>2]=e[k>>>2]else c.push.apply(c,e)this.sigBytes+=areturn this},clamp:function(){var a=this.words,c=this.sigBytesa[c>>>2]&=4294967295<<
32-8*(c%4)a.length=u.ceil(c/4)},clone:function(){var a=t.clone.call(this)a.words=this.words.slice(0)return a},random:function(a){for(var c=[],e=0e<ae+=4)c.push(4294967296*u.random()|0)return new r.init(c,a)}}),w=d.enc={},v=w.Hex={stringify:function(a){var c=a.wordsa=a.sigBytesfor(var e=[],j=0j<aj++){var k=c[j>>>2]>>>24-8*(j%4)&255e.push((k>>>4).toString(16))e.push((k&15).toString(16))}return e.join("")},parse:function(a){for(var c=a.length,e=[],j=0j<cj+=2)e[j>>>3]|=parseInt(a.substr(j,
2),16)<<24-4*(j%8)return new r.init(e,c/2)}},b=w.Latin1={stringify:function(a){var c=a.wordsa=a.sigBytesfor(var e=[],j=0j<aj++)e.push(String.fromCharCode(c[j>>>2]>>>24-8*(j%4)&255))return e.join("")},parse:function(a){for(var c=a.length,e=[],j=0j<cj++)e[j>>>2]|=(a.charCodeAt(j)&255)<<24-8*(j%4)return new r.init(e,c)}},x=w.Utf8={stringify:function(a){try{return decodeURIComponent(escape(b.stringify(a)))}catch(c){throw Error("Malformed UTF-8 data")}},parse:function(a){return b.parse(unescape(encodeURIComponent(a)))}},
q=l.BufferedBlockAlgorithm=t.extend({reset:function(){this._data=new r.initthis._nDataBytes=0},_append:function(a){"string"==typeof a&&(a=x.parse(a))this._data.concat(a)this._nDataBytes+=a.sigBytes},_process:function(a){var c=this._data,e=c.words,j=c.sigBytes,k=this.blockSize,b=j/(4*k),b=a?u.ceil(b):u.max((b|0)-this._minBufferSize,0)a=b*kj=u.min(4*a,j)if(a){for(var q=0q<aq+=k)this._doProcessBlock(e,q)q=e.splice(0,a)c.sigBytes-=j}return new r.init(q,j)},clone:function(){var a=t.clone.call(this)
a._data=this._data.clone()return a},_minBufferSize:0})l.Hasher=q.extend({cfg:t.extend(),init:function(a){this.cfg=this.cfg.extend(a)this.reset()},reset:function(){q.reset.call(this)this._doReset()},update:function(a){this._append(a)this._process()return this},finalize:function(a){a&&this._append(a)return this._doFinalize()},blockSize:16,_createHelper:function(a){return function(b,e){return(new a.init(e)).finalize(b)}},_createHmacHelper:function(a){return function(b,e){return(new n.HMAC.init(a,
e)).finalize(b)}}})var n=d.algo={}return d}(Math)
(function(){var u=CryptoJS,p=u.lib.WordArrayu.enc.Base64={stringify:function(d){var l=d.words,p=d.sigBytes,t=this._mapd.clamp()d=[]for(var r=0r<pr+=3)for(var w=(l[r>>>2]>>>24-8*(r%4)&255)<<16|(l[r+1>>>2]>>>24-8*((r+1)%4)&255)<<8|l[r+2>>>2]>>>24-8*((r+2)%4)&255,v=04>v&&r+0.75*v<pv++)d.push(t.charAt(w>>>6*(3-v)&63))if(l=t.charAt(64))for(d.length%4)d.push(l)return d.join("")},parse:function(d){var l=d.length,s=this._map,t=s.charAt(64)t&&(t=d.indexOf(t),-1!=t&&(l=t))for(var t=[],r=0,w=0w<
lw++)if(w%4){var v=s.indexOf(d.charAt(w-1))<<2*(w%4),b=s.indexOf(d.charAt(w))>>>6-2*(w%4)t[r>>>2]|=(v|b)<<24-8*(r%4)r++}return p.create(t,r)},_map:"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/="}})()
(function(u){function p(b,n,a,c,e,j,k){b=b+(n&a|~n&c)+e+kreturn(b<<j|b>>>32-j)+n}function d(b,n,a,c,e,j,k){b=b+(n&c|a&~c)+e+kreturn(b<<j|b>>>32-j)+n}function l(b,n,a,c,e,j,k){b=b+(n^a^c)+e+kreturn(b<<j|b>>>32-j)+n}function s(b,n,a,c,e,j,k){b=b+(a^(n|~c))+e+kreturn(b<<j|b>>>32-j)+n}for(var t=CryptoJS,r=t.lib,w=r.WordArray,v=r.Hasher,r=t.algo,b=[],x=064>xx++)b[x]=4294967296*u.abs(u.sin(x+1))|0r=r.MD5=v.extend({_doReset:function(){this._hash=new w.init([1732584193,4023233417,2562383102,271733878])},
_doProcessBlock:function(q,n){for(var a=016>aa++){var c=n+a,e=q[c]q[c]=(e<<8|e>>>24)&16711935|(e<<24|e>>>8)&4278255360}var a=this._hash.words,c=q[n+0],e=q[n+1],j=q[n+2],k=q[n+3],z=q[n+4],r=q[n+5],t=q[n+6],w=q[n+7],v=q[n+8],A=q[n+9],B=q[n+10],C=q[n+11],u=q[n+12],D=q[n+13],E=q[n+14],x=q[n+15],f=a[0],m=a[1],g=a[2],h=a[3],f=p(f,m,g,h,c,7,b[0]),h=p(h,f,m,g,e,12,b[1]),g=p(g,h,f,m,j,17,b[2]),m=p(m,g,h,f,k,22,b[3]),f=p(f,m,g,h,z,7,b[4]),h=p(h,f,m,g,r,12,b[5]),g=p(g,h,f,m,t,17,b[6]),m=p(m,g,h,f,w,22,b[7]),
f=p(f,m,g,h,v,7,b[8]),h=p(h,f,m,g,A,12,b[9]),g=p(g,h,f,m,B,17,b[10]),m=p(m,g,h,f,C,22,b[11]),f=p(f,m,g,h,u,7,b[12]),h=p(h,f,m,g,D,12,b[13]),g=p(g,h,f,m,E,17,b[14]),m=p(m,g,h,f,x,22,b[15]),f=d(f,m,g,h,e,5,b[16]),h=d(h,f,m,g,t,9,b[17]),g=d(g,h,f,m,C,14,b[18]),m=d(m,g,h,f,c,20,b[19]),f=d(f,m,g,h,r,5,b[20]),h=d(h,f,m,g,B,9,b[21]),g=d(g,h,f,m,x,14,b[22]),m=d(m,g,h,f,z,20,b[23]),f=d(f,m,g,h,A,5,b[24]),h=d(h,f,m,g,E,9,b[25]),g=d(g,h,f,m,k,14,b[26]),m=d(m,g,h,f,v,20,b[27]),f=d(f,m,g,h,D,5,b[28]),h=d(h,f,
m,g,j,9,b[29]),g=d(g,h,f,m,w,14,b[30]),m=d(m,g,h,f,u,20,b[31]),f=l(f,m,g,h,r,4,b[32]),h=l(h,f,m,g,v,11,b[33]),g=l(g,h,f,m,C,16,b[34]),m=l(m,g,h,f,E,23,b[35]),f=l(f,m,g,h,e,4,b[36]),h=l(h,f,m,g,z,11,b[37]),g=l(g,h,f,m,w,16,b[38]),m=l(m,g,h,f,B,23,b[39]),f=l(f,m,g,h,D,4,b[40]),h=l(h,f,m,g,c,11,b[41]),g=l(g,h,f,m,k,16,b[42]),m=l(m,g,h,f,t,23,b[43]),f=l(f,m,g,h,A,4,b[44]),h=l(h,f,m,g,u,11,b[45]),g=l(g,h,f,m,x,16,b[46]),m=l(m,g,h,f,j,23,b[47]),f=s(f,m,g,h,c,6,b[48]),h=s(h,f,m,g,w,10,b[49]),g=s(g,h,f,m,
E,15,b[50]),m=s(m,g,h,f,r,21,b[51]),f=s(f,m,g,h,u,6,b[52]),h=s(h,f,m,g,k,10,b[53]),g=s(g,h,f,m,B,15,b[54]),m=s(m,g,h,f,e,21,b[55]),f=s(f,m,g,h,v,6,b[56]),h=s(h,f,m,g,x,10,b[57]),g=s(g,h,f,m,t,15,b[58]),m=s(m,g,h,f,D,21,b[59]),f=s(f,m,g,h,z,6,b[60]),h=s(h,f,m,g,C,10,b[61]),g=s(g,h,f,m,j,15,b[62]),m=s(m,g,h,f,A,21,b[63])a[0]=a[0]+f|0a[1]=a[1]+m|0a[2]=a[2]+g|0a[3]=a[3]+h|0},_doFinalize:function(){var b=this._data,n=b.words,a=8*this._nDataBytes,c=8*b.sigBytesn[c>>>5]|=128<<24-c%32var e=u.floor(a/
4294967296)n[(c+64>>>9<<4)+15]=(e<<8|e>>>24)&16711935|(e<<24|e>>>8)&4278255360n[(c+64>>>9<<4)+14]=(a<<8|a>>>24)&16711935|(a<<24|a>>>8)&4278255360b.sigBytes=4*(n.length+1)this._process()b=this._hashn=b.wordsfor(a=04>aa++)c=n[a],n[a]=(c<<8|c>>>24)&16711935|(c<<24|c>>>8)&4278255360return b},clone:function(){var b=v.clone.call(this)b._hash=this._hash.clone()return b}})t.MD5=v._createHelper(r)t.HmacMD5=v._createHmacHelper(r)})(Math)
(function(){var u=CryptoJS,p=u.lib,d=p.Base,l=p.WordArray,p=u.algo,s=p.EvpKDF=d.extend({cfg:d.extend({keySize:4,hasher:p.MD5,iterations:1}),init:function(d){this.cfg=this.cfg.extend(d)},compute:function(d,r){for(var p=this.cfg,s=p.hasher.create(),b=l.create(),u=b.words,q=p.keySize,p=p.iterationsu.length<q){n&&s.update(n)var n=s.update(d).finalize(r)s.reset()for(var a=1a<pa++)n=s.finalize(n),s.reset()b.concat(n)}b.sigBytes=4*qreturn b}})u.EvpKDF=function(d,l,p){return s.create(p).compute(d,
l)}})()
CryptoJS.lib.Cipher||function(u){var p=CryptoJS,d=p.lib,l=d.Base,s=d.WordArray,t=d.BufferedBlockAlgorithm,r=p.enc.Base64,w=p.algo.EvpKDF,v=d.Cipher=t.extend({cfg:l.extend(),createEncryptor:function(e,a){return this.create(this._ENC_XFORM_MODE,e,a)},createDecryptor:function(e,a){return this.create(this._DEC_XFORM_MODE,e,a)},init:function(e,a,b){this.cfg=this.cfg.extend(b)this._xformMode=ethis._key=athis.reset()},reset:function(){t.reset.call(this)this._doReset()},process:function(e){this._append(e)return this._process()},
finalize:function(e){e&&this._append(e)return this._doFinalize()},keySize:4,ivSize:4,_ENC_XFORM_MODE:1,_DEC_XFORM_MODE:2,_createHelper:function(e){return{encrypt:function(b,k,d){return("string"==typeof k?c:a).encrypt(e,b,k,d)},decrypt:function(b,k,d){return("string"==typeof k?c:a).decrypt(e,b,k,d)}}}})d.StreamCipher=v.extend({_doFinalize:function(){return this._process(!0)},blockSize:1})var b=p.mode={},x=function(e,a,b){var c=this._ivc?this._iv=u:c=this._prevBlockfor(var d=0d<bd++)e[a+d]^=
c[d]},q=(d.BlockCipherMode=l.extend({createEncryptor:function(e,a){return this.Encryptor.create(e,a)},createDecryptor:function(e,a){return this.Decryptor.create(e,a)},init:function(e,a){this._cipher=ethis._iv=a}})).extend()q.Encryptor=q.extend({processBlock:function(e,a){var b=this._cipher,c=b.blockSizex.call(this,e,a,c)b.encryptBlock(e,a)this._prevBlock=e.slice(a,a+c)}})q.Decryptor=q.extend({processBlock:function(e,a){var b=this._cipher,c=b.blockSize,d=e.slice(a,a+c)b.decryptBlock(e,a)x.call(this,
e,a,c)this._prevBlock=d}})b=b.CBC=qq=(p.pad={}).Pkcs7={pad:function(a,b){for(var c=4*b,c=c-a.sigBytes%c,d=c<<24|c<<16|c<<8|c,l=[],n=0n<cn+=4)l.push(d)c=s.create(l,c)a.concat(c)},unpad:function(a){a.sigBytes-=a.words[a.sigBytes-1>>>2]&255}}d.BlockCipher=v.extend({cfg:v.cfg.extend({mode:b,padding:q}),reset:function(){v.reset.call(this)var a=this.cfg,b=a.iv,a=a.modeif(this._xformMode==this._ENC_XFORM_MODE)var c=a.createEncryptorelse c=a.createDecryptor,this._minBufferSize=1this._mode=c.call(a,
this,b&&b.words)},_doProcessBlock:function(a,b){this._mode.processBlock(a,b)},_doFinalize:function(){var a=this.cfg.paddingif(this._xformMode==this._ENC_XFORM_MODE){a.pad(this._data,this.blockSize)var b=this._process(!0)}else b=this._process(!0),a.unpad(b)return b},blockSize:4})var n=d.CipherParams=l.extend({init:function(a){this.mixIn(a)},toString:function(a){return(a||this.formatter).stringify(this)}}),b=(p.format={}).OpenSSL={stringify:function(a){var b=a.ciphertexta=a.saltreturn(a?s.create([1398893684,
1701076831]).concat(a).concat(b):b).toString(r)},parse:function(a){a=r.parse(a)var b=a.wordsif(1398893684==b[0]&&1701076831==b[1]){var c=s.create(b.slice(2,4))b.splice(0,4)a.sigBytes-=16}return n.create({ciphertext:a,salt:c})}},a=d.SerializableCipher=l.extend({cfg:l.extend({format:b}),encrypt:function(a,b,c,d){d=this.cfg.extend(d)var l=a.createEncryptor(c,d)b=l.finalize(b)l=l.cfgreturn n.create({ciphertext:b,key:c,iv:l.iv,algorithm:a,mode:l.mode,padding:l.padding,blockSize:a.blockSize,formatter:d.format})},
decrypt:function(a,b,c,d){d=this.cfg.extend(d)b=this._parse(b,d.format)return a.createDecryptor(c,d).finalize(b.ciphertext)},_parse:function(a,b){return"string"==typeof a?b.parse(a,this):a}}),p=(p.kdf={}).OpenSSL={execute:function(a,b,c,d){d||(d=s.random(8))a=w.create({keySize:b+c}).compute(a,d)c=s.create(a.words.slice(b),4*c)a.sigBytes=4*breturn n.create({key:a,iv:c,salt:d})}},c=d.PasswordBasedCipher=a.extend({cfg:a.cfg.extend({kdf:p}),encrypt:function(b,c,d,l){l=this.cfg.extend(l)d=l.kdf.execute(d,
b.keySize,b.ivSize)l.iv=d.ivb=a.encrypt.call(this,b,c,d.key,l)b.mixIn(d)return b},decrypt:function(b,c,d,l){l=this.cfg.extend(l)c=this._parse(c,l.format)d=l.kdf.execute(d,b.keySize,b.ivSize,c.salt)l.iv=d.ivreturn a.decrypt.call(this,b,c,d.key,l)}})}()
(function(){for(var u=CryptoJS,p=u.lib.BlockCipher,d=u.algo,l=[],s=[],t=[],r=[],w=[],v=[],b=[],x=[],q=[],n=[],a=[],c=0256>cc++)a[c]=128>c?c<<1:c<<1^283for(var e=0,j=0,c=0256>cc++){var k=j^j<<1^j<<2^j<<3^j<<4,k=k>>>8^k&255^99l[e]=ks[k]=evar z=a[e],F=a[z],G=a[F],y=257*a[k]^16843008*kt[e]=y<<24|y>>>8r[e]=y<<16|y>>>16w[e]=y<<8|y>>>24v[e]=yy=16843009*G^65537*F^257*z^16843008*eb[k]=y<<24|y>>>8x[k]=y<<16|y>>>16q[k]=y<<8|y>>>24n[k]=ye?(e=z^a[a[a[G^z]]],j^=a[a[j]]):e=j=1}var H=[0,1,2,4,8,
16,32,64,128,27,54],d=d.AES=p.extend({_doReset:function(){for(var a=this._key,c=a.words,d=a.sigBytes/4,a=4*((this._nRounds=d+6)+1),e=this._keySchedule=[],j=0j<aj++)if(j<d)e[j]=c[j]else{var k=e[j-1]j%d?6<d&&4==j%d&&(k=l[k>>>24]<<24|l[k>>>16&255]<<16|l[k>>>8&255]<<8|l[k&255]):(k=k<<8|k>>>24,k=l[k>>>24]<<24|l[k>>>16&255]<<16|l[k>>>8&255]<<8|l[k&255],k^=H[j/d|0]<<24)e[j]=e[j-d]^k}c=this._invKeySchedule=[]for(d=0d<ad++)j=a-d,k=d%4?e[j]:e[j-4],c[d]=4>d||4>=j?k:b[l[k>>>24]]^x[l[k>>>16&255]]^q[l[k>>>
8&255]]^n[l[k&255]]},encryptBlock:function(a,b){this._doCryptBlock(a,b,this._keySchedule,t,r,w,v,l)},decryptBlock:function(a,c){var d=a[c+1]a[c+1]=a[c+3]a[c+3]=dthis._doCryptBlock(a,c,this._invKeySchedule,b,x,q,n,s)d=a[c+1]a[c+1]=a[c+3]a[c+3]=d},_doCryptBlock:function(a,b,c,d,e,j,l,f){for(var m=this._nRounds,g=a[b]^c[0],h=a[b+1]^c[1],k=a[b+2]^c[2],n=a[b+3]^c[3],p=4,r=1r<mr++)var q=d[g>>>24]^e[h>>>16&255]^j[k>>>8&255]^l[n&255]^c[p++],s=d[h>>>24]^e[k>>>16&255]^j[n>>>8&255]^l[g&255]^c[p++],t=
d[k>>>24]^e[n>>>16&255]^j[g>>>8&255]^l[h&255]^c[p++],n=d[n>>>24]^e[g>>>16&255]^j[h>>>8&255]^l[k&255]^c[p++],g=q,h=s,k=tq=(f[g>>>24]<<24|f[h>>>16&255]<<16|f[k>>>8&255]<<8|f[n&255])^c[p++]s=(f[h>>>24]<<24|f[k>>>16&255]<<16|f[n>>>8&255]<<8|f[g&255])^c[p++]t=(f[k>>>24]<<24|f[n>>>16&255]<<16|f[g>>>8&255]<<8|f[h&255])^c[p++]n=(f[n>>>24]<<24|f[g>>>16&255]<<16|f[h>>>8&255]<<8|f[k&255])^c[p++]a[b]=qa[b+1]=sa[b+2]=ta[b+3]=n},keySize:8})u.AES=p._createHelper(d)})()
pad-zeropadding.js
/*
CryptoJS v3.1.2
code.google.com/p/crypto-js
(c) 2009-2013 by Jeff Mott. All rights reserved.
code.google.com/p/crypto-js/wiki/License
*/
/**
* Zero padding strategy.
*/
CryptoJS.pad.ZeroPadding = {
pad: function (data, blockSize) {
// Shortcut
var blockSizeBytes = blockSize * 4
// Pad
data.clamp()
data.sigBytes += blockSizeBytes - ((data.sigBytes % blockSizeBytes) || blockSizeBytes)
},
unpad: function (data) {
// Shortcut
var dataWords = data.words
// Unpad
var i = data.sigBytes - 1
while (!((dataWords[i >>>2] >>>(24 - (i % 4) * 8)) &0xff)) {
i--
}
data.sigBytes = i + 1
}
}
一、无需任何PHP扩展的加密
此类加密的代表有 威盾PHP加密专家、PHP在线加密平台、PHP神盾 等。
此类加密都是以eval函数为核心，辅以各式各样的字符串混淆和各种小技巧，来达到加密目的（更准确的说，应该算是混淆）。下面以一个简单的hello world为例来说明此类加密的大体过程。
<?php
echo "hello world"
首先 ，我们把这段代码变为通过eval执行的
<?php
eval('echo "hello world"')
然后 ，我们再进行一些转换，比如说base64编码
<?php
eval(base64_decode('ZWNobyAiaGVsbG8gd29ybGQiOw=='))
就这样子，我们的第一个加密过的php代码新鲜出炉了。。。
上面这个例子非常非常简单，基本上任何有一点php语言基础甚至别的语言基础的人都能轻松的看懂并解密。因此，我们需要一些方法让这个加密至少看上去不是那么简单。
二、同时采用多种编码函数
除了刚才提到的base64，php还有许多内置的编码函数，例如urlencode、gzcompress等。把这些函数混合使用可以提高解密的复杂度（不是难度），此外还可以使用strtr来制定自己的编码规则。 使用变量来代替函数名 使用特定字符来命名变量
这儿所说的特定字符是一些极其相似的字符，如I和1，0和O。试想一下满屏都是O和0组成的变量，并且每一个的名字长度都在10个字符以上。。。 判断文件自身是否被修改
这个功能看似容易，对文件做一下摘要再进行下对比即可知道是否被修改了，但是如何才能在文件内把摘要嵌入进去呢？我没有找到完美的方案，但一个变通的方案还是很容易的。。。
<?php
$code = substr(file_get_contents(__FILE__), 0, -32)
$hash = substr(file_get_contents(__FILE__), -32)
if (md5($code) !== $hash) {
exit('file edited')
}
ACBC41F727E00F85BEB3440D751BB4E3
当然，你可以把这个校验字符串放在别的位置来提高破解的难度。有了这个，别人想破解你的程序可就得多费一点功夫了。。。
既然知道了原理，那解密自然也就非常简单了，总体来说就三步：
把eval替换为输出，比如echo 根据编码规则把字符串还原 如果文件未解密完全，从第一步开始继续
当然，实际上的解密过程并没有这么简单，比如说如果加密的时候使用了gzcompress，那得到的数据将会包含一些二进制数据，而采用一般的文本编辑器打开时这些数据都会显示为乱码，并且在保存时丢失部分数据。解决方法很简单也很麻烦，那就是使用二进制（16进制）方式打开、修改和保存。
前台加密
后台接收到后
在和盐值拼接
在加密
存入数据库
我用md5举例
前台:md5(pwd)
//前台找一个js加密扩展就行
后台:
$salt
=
mt_rand(100000,999999)
//随机盐值
$pwd
=
md5($_GET('pwd').$salt)
//这样双重加密后入库了
登录验证时
前台也记得加密哦
