js-confuser

JavaScript Obfuscation Tool.

Usage no npm install needed!

<script type="module">
  import jsConfuser from 'https://cdn.skypack.dev/js-confuser';
</script>

README

JS Confuser

JS-Confuser is a JavaScript obfuscation tool to make your programs impossible to read. Try the web version.

Key features

Presets

JS-Confuser comes with three presets built into the obfuscator.

Preset Transforms Performance Reduction Sample
High 21/22 98% Sample
Medium 15/22 52% Sample
Low 10/22 30% Sample

You can extend each preset or all go without them entirely.

Installation

$ npm install js-confuser

Usage

var JsConfuser = require("js-confuser");

JsConfuser.obfuscate(`
  function fibonacci(num){   
    var a = 0, b = 1, c = num;
    while (num-- > 1) {
      c = a + b;
      a = b;
      b = c;
    }
    return c;
  }

  for ( var i = 1; i <= 25; i++ ) {
    console.log(i, fibonacci(i))
  }
`, {
  target: "node",
  preset: "high",
  stringEncoding: false, // <- Normally enabled
}).then(obfuscated => {
  console.log(obfuscated)
})

/*
var AF59rI,ZgbbeaU,WDgj3I,gpR2qG,Ox61sk,pTNPNpX;AF59rI=[60,17,25,416,22,23,83,26,27,28,18,382,66,29,30,31,2,5,33,4,13,16,10,11,24,1,3,15,6,7,8,167,50,9,21,35,12,14,116],ZgbbeaU=AF59rI;for(var TlMIASm=62;TlMIASm;TlMIASm--)ZgbbeaU.unshift(ZgbbeaU.pop());WDgj3I=MBh_HcM("length1charCodeAt1slice1replaĕ1!ğğ1uģģ1<~A8bt#D.RU,~>Ħ~E,ol,ATMnijĵ@rH7+DertŀħDKTtlBhE[ŋ~@q]:k6Z6LHŖ6$*Ŗ7n#j;20AŖ;g3Cn<]'Ŗ<Fna!Cii#ŖAU&0.Eb0;TŖ4ƌĴħ3rƍ)eVMBK\\!Ŗ+=M;Q@;]UaŖž=3&.0Ŗ/M2-WEcYr5ŖD?ƯTqŸb>-Q:c8Ŗ?SF2m2*!WQŖ2)RIJƐ~ž<ƿĴmČuĀ1 (local)").split('1');function pprWr0(ZgbbeaU){var WDgj3I,gpR2qG,Ox61sk,pTNPNpX,TlMIASm,pprWr0,M1ClYmT,kHWl72,xw_ohrD,sT8e3fv,bxd0KVG;WDgj3I=void 0,gpR2qG=void 0,Ox61sk=void 0,pTNPNpX=void 0,TlMIASm=void 0,pprWr0=String,M1ClYmT=CVH25o3(0),kHWl72=255,xw_ohrD=CVH25o3(1),sT8e3fv=CVH25o3(AF59rI[0]),bxd0KVG=CVH25o3(3);for('<~'===ZgbbeaU[sT8e3fv](0,AF59rI[0])&&'~>'===ZgbbeaU[sT8e3fv](-AF59rI[0]),ZgbbeaU=ZgbbeaU[sT8e3fv](AF59rI[0],-AF59rI[0])[bxd0KVG](/s/g,'')[bxd0KVG]('z',CVH25o3(AF59rI[3])),WDgj3I=CVH25o3(AF59rI[1])[sT8e3fv](ZgbbeaU[M1ClYmT]%AF59rI[1]||AF59rI[1]),ZgbbeaU+=WDgj3I,Ox61sk=[],pTNPNpX=0,TlMIASm=ZgbbeaU[M1ClYmT];TlMIASm>pTNPNpX;pTNPNpX+=AF59rI[1])gpR2qG=52200625*(ZgbbeaU[xw_ohrD](pTNPNpX)-AF59rI[2])+614125*(ZgbbeaU[xw_ohrD](pTNPNpX+AF59rI[9])-AF59rI[2])+7225*(ZgbbeaU[xw_ohrD](pTNPNpX+AF59rI[0])-AF59rI[2])+85*(ZgbbeaU[xw_ohrD](pTNPNpX+AF59rI[10])-AF59rI[2])+(ZgbbeaU[xw_ohrD](pTNPNpX+AF59rI[3])-AF59rI[2]),Ox61sk.push(kHWl72&gpR2qG>>AF59rI[8],kHWl72&gpR2qG>>AF59rI[5],kHWl72&gpR2qG>>8,kHWl72&gpR2qG);return function(ZgbbeaU,Ox61sk){for(var WDgj3I=Ox61sk;WDgj3I>0;WDgj3I--)ZgbbeaU.pop()}(Ox61sk,WDgj3I[M1ClYmT]),pprWr0.fromCharCode.apply(pprWr0,Ox61sk)}gpR2qG=[CVH25o3(AF59rI[12]),CVH25o3(AF59rI[13]),CVH25o3(8),CVH25o3(AF59rI[17]),CVH25o3(AF59rI[6]),CVH25o3(AF59rI[7]),CVH25o3(AF59rI[20]),'<~AQO1jBl7V~>',CVH25o3(AF59rI[4]),CVH25o3(AF59rI[21]),CVH25o3(AF59rI[4]),CVH25o3(9),CVH25o3(AF59rI[11]),CVH25o3(AF59rI[5]),CVH25o3(AF59rI[24]),CVH25o3(AF59rI[33]),'<~E%u9/13QC~>',CVH25o3(AF59rI[6]),CVH25o3(AF59rI[7]),CVH25o3(19),CVH25o3(20),CVH25o3(AF59rI[18]),CVH25o3(AF59rI[27]),CVH25o3(AF59rI[28]),CVH25o3(AF59rI[8]),'<~?T9_t1,(IC~>','<~1bpf~>',CVH25o3(AF59rI[25]),CVH25o3(AF59rI[30]),CVH25o3(AF59rI[31]),CVH25o3(14),CVH25o3(AF59rI[8])];function M1ClYmT(AF59rI){return pprWr0(gpR2qG[AF59rI])}function kHWl72(){try{return global}catch(AF59rI){return this}}Ox61sk=kHWl72.call(this);function xw_ohrD(ZgbbeaU){switch(ZgbbeaU){case 608:return Ox61sk[M1ClYmT(0)];case-884:return Ox61sk[CVH25o3(AF59rI[32])];case AF59rI[26]:return Ox61sk[M1ClYmT(AF59rI[9])];case-AF59rI[35]:return Ox61sk[M1ClYmT(2)]}}function sT8e3fv(ZgbbeaU,WDgj3I,gpR2qG){var Ox61sk;Ox61sk=11;while(Ox61sk!=51){var pTNPNpX,TlMIASm,pprWr0,kHWl72;pTNPNpX=Ox61sk*-244+217;switch(pTNPNpX){case-2467:TlMIASm=false,Ox61sk+=37;break;case-4175:kHWl72=WDgj3I==M1ClYmT(AF59rI[10])&&ziPI9L.qzUvJu1[M1ClYmT(4)+M1ClYmT(AF59rI[1])](AF59rI[9])==48?function(...WDgj3I){var gpR2qG;gpR2qG=AF59rI[1];while(gpR2qG!=AF59rI[11]){var Ox61sk;Ox61sk=gpR2qG*41+199;switch(Ox61sk){case 732:return pprWr0[ZgbbeaU].call(this,M1ClYmT(AF59rI[12]));case 404:IZftqI=WDgj3I,gpR2qG+=AF59rI[14]}}}:pprWr0[ZgbbeaU](M1ClYmT(AF59rI[13])),Ox61sk-=AF59rI[10];break;case-11495:pprWr0={[M1ClYmT(AF59rI[14])]:function(ZgbbeaU,WDgj3I,gpR2qG){var Ox61sk;Ox61sk=64;while(Ox61sk!=AF59rI[16]){var pTNPNpX,TlMIASm,pprWr0;pTNPNpX=Ox61sk*AF59rI[15]+144;switch(pTNPNpX){case 10832:TlMIASm=822,Ox61sk+=AF59rI[10];break;case 812:pprWr0[AF59rI[10]]=pprWr0[0],Ox61sk+=47;break;case 8661:while(TlMIASm!=772){var kHWl72;kHWl72=TlMIASm*234+191;switch(kHWl72){case 207515:TlMIASm-=528;break;case 129593:pprWr0[3]=bxd0KVG(AF59rI[15],pprWr0[AF59rI[9]],pprWr0[AF59rI[0]]),pprWr0[AF59rI[9]]=pprWr0[AF59rI[0]],pprWr0[AF59rI[0]]=pprWr0[AF59rI[10]],TlMIASm+=333;break;case 83963:TlMIASm+=bxd0KVG(-AF59rI[29],pprWr0[0]--,AF59rI[9])&&ziPI9L.U1LXDgJ()?195:414;break;case 192539:TlMIASm-=464}}Ox61sk-=AF59rI[16];break;case 10999:[...pprWr0]=IZftqI,pprWr0.length=1,Ox61sk-=AF59rI[38];break;case 6824:return[];case 11333:if(!ZgbbeaU){return WDgj3I(this,gpR2qG)}Ox61sk-=AF59rI[0];break;case 311:return[pprWr0[AF59rI[10]]];case 5822:pprWr0[1]=0,pprWr0[AF59rI[0]]=AF59rI[9],Ox61sk-=AF59rI[37]}}},[M1ClYmT(AF59rI[17])]:function(ZgbbeaU,WDgj3I,gpR2qG){var Ox61sk;Ox61sk=AF59rI[18];while(Ox61sk!=38){var pTNPNpX,TlMIASm,pprWr0;pTNPNpX=Ox61sk*182+-139;switch(pTNPNpX){case 4047:pprWr0[AF59rI[9]]=sT8e3fv(M1ClYmT(AF59rI[6]),M1ClYmT(AF59rI[7])).call([],pprWr0[0]),Ox61sk+=AF59rI[19];break;case 3683:TlMIASm=false,Ox61sk+=21;break;case 7505:[...pprWr0]=IZftqI,Ox61sk-=10;break;case 225:return pprWr0[AF59rI[9]].pop();case 10417:if(TlMIASm){var kHWl72=(ZgbbeaU,WDgj3I,gpR2qG)=>{var Ox61sk;Ox61sk=32;while(Ox61sk!=AF59rI[19]){var pTNPNpX,TlMIASm,pprWr0;pTNPNpX=Ox61sk*38+90;switch(pTNPNpX){case 508:TlMIASm=bxd0KVG(AF59rI[15],M1ClYmT(AF59rI[20]),pprWr0.toUTCString()),Ox61sk+=AF59rI[21];break;case 584:pprWr0.setTime(bxd0KVG(AF59rI[15],pprWr0.getTime(),bxd0KVG(AF59rI[22],bxd0KVG(116,bxd0KVG(AF59rI[22],bxd0KVG(116,gpR2qG,AF59rI[8]),AF59rI[23]),AF59rI[23]),1e3))),Ox61sk-=2;break;case 1040:xw_ohrD(608).cookie=bxd0KVG(AF59rI[15],bxd0KVG(AF59rI[15],bxd0KVG(AF59rI[15],bxd0KVG(AF59rI[15],bxd0KVG(AF59rI[15],ZgbbeaU,M1ClYmT(AF59rI[4])),WDgj3I),M1ClYmT(AF59rI[21])),TlMIASm),M1ClYmT(15)),Ox61sk+=AF59rI[6];break;case 1306:pprWr0=new Date,Ox61sk-=19}}}}Ox61sk-=56;break;case 5685:pprWr0.length=1,Ox61sk-=AF59rI[17]}}}},Ox61sk-=43;break;case-14179:kHWl72=void 0;if(WDgj3I==M1ClYmT(AF59rI[5])&&ziPI9L.VNaV0wv[M1ClYmT(AF59rI[24])+M1ClYmT(18)](AF59rI[6])==AF59rI[16]){IZftqI=[]}Ox61sk-=41;break;case-1003:if(TlMIASm){xw_ohrD(-884).exports=async()=>{var ZgbbeaU;ZgbbeaU=33;while(ZgbbeaU!=AF59rI[7]){var WDgj3I,gpR2qG,Ox61sk;WDgj3I=ZgbbeaU*95+-150;switch(WDgj3I){case 3175:gpR2qG=await(async()=>{var ZgbbeaU;ZgbbeaU=14;while(ZgbbeaU!=AF59rI[13]){var WDgj3I;WDgj3I=ZgbbeaU*100+-59;switch(WDgj3I){case 1341:if(isStandaloneExecutable){return M1ClYmT(19)+M1ClYmT(20)}ZgbbeaU+=AF59rI[6];break;case 2341:if(redactedPath===await resolveLocalredactedPath()){return CVH25o3(AF59rI[36])}ZgbbeaU-=AF59rI[13];break;case 1641:return''}}})(),ZgbbeaU-=AF59rI[25];break;case 2985:Ox61sk=new Set(xw_ohrD(AF59rI[26]).argv.slice(2)),ZgbbeaU-=AF59rI[6];break;case 2035:if(!Ox61sk.has(M1ClYmT(AF59rI[18])+M1ClYmT(AF59rI[27]))){var pTNPNpX;pTNPNpX=AF59rI[14];while(pTNPNpX!=9){var TlMIASm;TlMIASm=pTNPNpX*-204+38;switch(TlMIASm){case-1594:if(bxd0KVG(427,Ox61sk.size,1)){return false}pTNPNpX-=AF59rI[3];break;case-778:if(!Ox61sk.has(M1ClYmT(AF59rI[28]))){return false}pTNPNpX+=AF59rI[1]}}}ZgbbeaU+=AF59rI[20];break;case 800:return true}}}}Ox61sk+=54;break;case-3443:return gpR2qG==M1ClYmT(AF59rI[8])&&ziPI9L.U1LXDgJ()?{QVbrqy9:kHWl72}:kHWl72}}}function bxd0KVG(ZgbbeaU,WDgj3I,gpR2qG){switch(ZgbbeaU){case-AF59rI[34]:return WDgj3I<=gpR2qG;case-AF59rI[29]:return WDgj3I>gpR2qG;case AF59rI[15]:return WDgj3I+gpR2qG;case AF59rI[22]:return WDgj3I*gpR2qG;case 427:return WDgj3I!==gpR2qG}}pTNPNpX=AF59rI[12];while(pTNPNpX!=AF59rI[24]){var kBznIi,sCb8UYh,ziPI9L,IZftqI;kBznIi=pTNPNpX*-55+-214;switch(kBznIi){case-544:sCb8UYh=846,pTNPNpX+=AF59rI[0];break;case-654:ziPI9L={wHDYSl:[],U1LXDgJ:function(){if(!ziPI9L.wHDYSl[0]){ziPI9L.wHDYSl.push(87)}return ziPI9L.wHDYSl.length},VNaV0wv:M1ClYmT(AF59rI[25])+M1ClYmT(AF59rI[30]),qzUvJu1:M1ClYmT(AF59rI[31])+M1ClYmT(AF59rI[32])},pTNPNpX+=AF59rI[33];break;case-1644:IZftqI=[],pTNPNpX-=7;break;case-1259:while(sCb8UYh!=316){var XsBuZX,mgjtps2;XsBuZX=sCb8UYh*229+-125;switch(XsBuZX){case 193609:mgjtps2=AF59rI[9],sCb8UYh-=733;break;case 25752:sCb8UYh+=bxd0KVG(-AF59rI[34],mgjtps2,25)&&ziPI9L.U1LXDgJ()?662:203;break;case 177350:xw_ohrD(-AF59rI[35])[M1ClYmT(AF59rI[36])](mgjtps2,(IZftqI=[mgjtps2],new sT8e3fv(M1ClYmT(AF59rI[37]),void 0,M1ClYmT(AF59rI[38])).QVbrqy9)),sCb8UYh-=569;break;case 47049:mgjtps2++,sCb8UYh-=93}}pTNPNpX-=AF59rI[0]}}function CVH25o3(AF59rI){return WDgj3I[AF59rI]}function MBh_HcM(ZgbbeaU){var WDgj3I,gpR2qG,Ox61sk,pTNPNpX,TlMIASm,pprWr0,M1ClYmT,kHWl72;WDgj3I=void 0,gpR2qG=void 0,Ox61sk=void 0,pTNPNpX={},TlMIASm=ZgbbeaU.split(''),pprWr0=gpR2qG=TlMIASm[0],M1ClYmT=[pprWr0],kHWl72=WDgj3I=256;for(ZgbbeaU=AF59rI[9];ZgbbeaU<TlMIASm.length;ZgbbeaU++)Ox61sk=TlMIASm[ZgbbeaU].charCodeAt(0),Ox61sk=kHWl72>Ox61sk?TlMIASm[ZgbbeaU]:pTNPNpX[Ox61sk]?pTNPNpX[Ox61sk]:gpR2qG+pprWr0,M1ClYmT.push(Ox61sk),pprWr0=Ox61sk.charAt(0),pTNPNpX[WDgj3I]=gpR2qG+pprWr0,WDgj3I++,gpR2qG=Ox61sk;return M1ClYmT.join('')}
*/

CLI Usage

<coming soon>

obfuscate(sourceCode, options)

Obfuscates the sourceCode. Returns a Promise that resolves to a string of the obfuscated code.

Parameter Type Description
sourceCode string The JavaScript code to be obfuscated.
options object The obfuscator settings.

obfuscateAST(AST, options)

Obfuscates an ESTree compliant AST. Returns a Promise.

Note: Mutates the object.

Parameter Type Description
AST object The ESTree compliant AST. This object will be mutated.
options object The obfuscator settings.

Options

target

The execution context for your output. Required.

  1. "node"
  2. "browser"

preset

JS-Confuser comes with three presets built into the obfuscator. Optional. ("high"/"medium"/"low")

var JsConfuser = require('js-confuser');

JsConfuser.obfuscate(`<source code>`, {
  target: "node",
  preset: "high" // | "medium" | "low"
}).then(obfuscated=>{
  console.log(obfuscated) // obfuscated is a string
})

compact

Remove's whitespace from the final output. Enabled by default. (true/false)

minify

Minifies redundant code. (true/false)

es5

Converts output to ES5-compatible code. (true/false)

Does not cover all cases such as Promises or Generator functions. Use Babel.

renameVariables

Determines if variables should be renamed. (true/false)

  • Potency High
  • Resilience High
  • Cost Medium

renameGlobals

Renames top-level variables, turn this off for web-related scripts. Enabled by default. (true/false)

identifierGenerator

Determines how variables are renamed.

Mode Description Example
"hexadecimal" Random hex strings _0xa8db5
"randomized" Random characters w$Tsu4G
"zeroWidth" Invisible characters U+200D
"mangled" Alphabet sequence a, b, c
"number" Numbered sequence var_1, var_2
<function> Write a custom name generator See Below 
// Custom implementation
JsConfuser.obfuscate(code, {
  target: "node",
  renameVariables: true,
  identifierGenerator: function () {
    return "quot; + Math.random().toString(36).substring(7);
  },
});

// Numbered variables
var counter = 0;
JsConfuser.obfuscate(code, {
  target: "node",
  renameVariables: true,
  identifierGenerator: function () {
    return "var_" + (counter++);
  },
});

JSConfuser tries to reuse names when possible, creating very potent code.

nameRecycling

⚠️ Experimental feature, may break your code!

Attempts to reuse released names.

  • Potency Medium
  • Resilience High
  • Cost Low
// Input
function percentage(x) {
  var multiplied = x * 100;
  var floored = Math.floor(multiplied);
  var output = floored + "%"
  return output;
}

// Output
function percentage(x) {
  var multiplied = x * 100;
  var floored = Math.floor(multiplied);
  multiplied = floored + "%";
  return multiplied;
}

controlFlowFlattening

⚠️ Significantly impacts performance, use sparingly!

Control-flow Flattening hinders program comprehension by creating convoluted switch statements. (true/false/0-1)

Use a number to control the percentage from 0 to 1.

  • Potency High
  • Resilience High
  • Cost High

globalConcealing

Global Concealing hides global variables being accessed. (true/false)

  • Potency Medium
  • Resilience High
  • Cost Low

stringCompression

String Compression uses LZW's compression algorithm to compress strings. (true/false/0-1)

"console" -> inflate('replaĕ!ğğuģģ<~@')

  • Potency High
  • Resilience Medium
  • Cost Medium

stringConcealing

String Concealing involves encoding strings to conceal plain-text values. (true/false/0-1)

Use a number to control the percentage of strings.

"console" -> decrypt('<~@rH7+Dert~>')

  • Potency High
  • Resilience Medium
  • Cost Medium

stringEncoding

String Encoding transforms a string into an encoded representation. (true/false/0-1)

Use a number to control the percentage of strings.

"console" -> '\x63\x6f\x6e\x73\x6f\x6c\x65'

  • Potency Low
  • Resilience Low
  • Cost Low

stringSplitting

String Splitting splits your strings into multiple expressions. (true/false/0-1)

Use a number to control the percentage of strings.

"console" -> String.fromCharCode(99) + 'ons' + 'ole'

  • Potency Medium
  • Resilience Medium
  • Cost Medium

duplicateLiteralsRemoval

Duplicate Literals Removal replaces duplicate literals with a single variable name. (true/false)

  • Potency Medium
  • Resilience Low
  • Cost High

dispatcher

Creates a middleman function to process function calls. (true/false/0-1)

  • Potency Medium
  • Resilience Medium
  • Cost High

eval

Security Warning

From MDN: Executing JavaScript from a string is an enormous security risk. It is far too easy for a bad actor to run arbitrary code when you use eval(). Never use eval()!

Wraps defined functions within eval statements.

  • false - Avoids using the eval function. Default.
  • true - Wraps function's code into an eval statement.
// Output.js
var Q4r1__ = {
  Oo$Oz8t: eval(
    "(function(YjVpAp){var gniSBq6=kHmsJrhOO;switch(gniSBq6){case'RW11Hj5x':return console;}});"
  ),
};
Q4r1__.Oo$Oz8t("RW11Hj5x");

rgf

RGF (Runtime-Generated-Functions) uses the new Function(code...) syntax to construct executable code from strings. ("all"/true/false)

  • This can break your code. This is also as dangerous as eval.
  • Due to the security concerns of arbitrary code execution, you must enable this yourself.
  • The arbitrary code is also obfuscated.
Mode Description
"all" Recursively applies to every scope (slow)
true Applies to the top level only
false Feature disabled 
// Input
function log(x){
  console.log(x)
}

log("Hello World")

// Output
var C6z0jyO=[new Function('a2Fjjl',"function OqNW8x(OqNW8x){console['log'](OqNW8x)}return OqNW8x(...Array.prototype.slice.call(arguments,1))")];(function(){return C6z0jyO[0](C6z0jyO,...arguments)}('Hello World'))

objectExtraction

Extracts object properties into separate variables. (true/false)

  • Potency Medium
  • Resilience Medium
  • Cost Low
// Input
var utils = {
  isString: x=>typeof x === "string",
  isBoolean: x=>typeof x === "boolean"
}
if ( utils.isString("Hello") ) {
  // ...
}

// Output
var utils_isString = x=>typeof x === "string";
var utils_isBoolean = x=>typeof x === "boolean";
if ( utils_isString("Hello") ) {
  // ...
}

flatten

Brings independent declarations to the highest scope. (true/false)

  • Potency Medium
  • Resilience Medium
  • Cost High

deadCode

Randomly injects dead code. (true/false/0-1)

Use a number to control the percentage from 0 to 1.

  • Potency Medium
  • Resilience Medium
  • Cost Low

calculator

Creates a calculator function to handle arithmetic and logical expressions. (true/false/0-1)

  • Potency Medium
  • Resilience Medium
  • Cost Low

lock.antiDebug

Adds debugger statements throughout the code. Additionally adds a background function for DevTools detection. (true/false/0-1)

lock.context

Properties that must be present on the window object (or global for NodeJS). (string[])

lock.startDate

When the program is first able to be used. (number or Date)

Number should be in milliseconds.

  • Potency Low
  • Resilience Medium
  • Cost Medium

lock.endDate

When the program is no longer able to be used. (number or Date)

Number should be in milliseconds.

  • Potency Low
  • Resilience Medium
  • Cost Medium

lock.domainLock

Array of regex strings that the window.location.href must follow. (Regex[] or string[])

  • Potency Low
  • Resilience Medium
  • Cost Medium

lock.osLock

Array of operating-systems where the script is allowed to run. (string[])

  • Potency Low
  • Resilience Medium
  • Cost Medium

Allowed values: "linux", "windows", "osx", "android", "ios"

Example: ["linux", "windows"]

lock.browserLock

Array of browsers where the script is allowed to run. (string[])

  • Potency Low
  • Resilience Medium
  • Cost Medium

Allowed values: "firefox", "chrome", "iexplorer", "edge", "safari", "opera"

Example: ["firefox", "chrome"]

lock.nativeFunctions

Set of global functions that are native. Such as require, fetch. If these variables are modified the program crashes. Set to true to use the default set of native functions. (string[]/true/false)

  • Potency Low
  • Resilience Medium
  • Cost Medium

lock.integrity

Integrity ensures the source code is unchanged. (true/false/0-1)

Learn more here.

  • Potency Medium
  • Resilience High
  • Cost High

lock.countermeasures

A custom callback function to invoke when a lock is triggered. (string/false)

Learn more about the countermeasures function.

Otherwise, the obfuscator falls back to crashing the process.

movedDeclarations

Moves variable declarations to the top of the context. (true/false)

  • Potency Medium
  • Resilience Medium
  • Cost Low

opaquePredicates

An Opaque Predicate is a predicate(true/false) that is evaluated at runtime, this can confuse reverse engineers from understanding your code. (true/false/0-1)

  • Potency Medium
  • Resilience Medium
  • Cost Low

shuffle

Shuffles the initial order of arrays. The order is brought back to the original during runtime. ("hash"/true/false/0-1)

  • Potency Medium
  • Resilience Low
  • Cost Low
Mode Description
"hash" Array is shifted based on hash of the elements
true Arrays are shifted n elements, unshifted at runtime
false Feature disabled

stack

Local variables are consolidated into a rotating array. (true/false/0-1)

Similar to Jscrambler's Variable Masking

  • Potency Medium
  • Resilience Medium
  • Cost Low
// Input
function add3(x, y, z){
  return x + y + z;
}

// Output
function iVQoGQD(...iVQoGQD){
  ~(iVQoGQD.length = 3, iVQoGQD[215] = iVQoGQD[2], iVQoGQD[75] = 227, iVQoGQD[iVQoGQD[75] - (iVQoGQD[75] - 75)] = iVQoGQD[75] - (iVQoGQD[75] - 239), iVQoGQD[iVQoGQD[iVQoGQD[75] - 164] - 127] = iVQoGQD[iVQoGQD[75] - 238], iVQoGQD[iVQoGQD[75] - 104] = iVQoGQD[75] - 482, iVQoGQD[iVQoGQD[135] + 378] = iVQoGQD[iVQoGQD[135] + 318] - 335, iVQoGQD[21] = iVQoGQD[iVQoGQD[135] + 96], iVQoGQD[iVQoGQD[iVQoGQD[75] - 104] - (iVQoGQD[75] - 502)] = iVQoGQD[iVQoGQD[75] - 164] - 440);
  return iVQoGQD[75] > iVQoGQD[75] + 90 ? iVQoGQD[iVQoGQD[135] - (iVQoGQD[135] + 54)] : iVQoGQD[iVQoGQD[135] + 117] + iVQoGQD[iVQoGQD[iVQoGQD[75] - (iVQoGQD[75] - (iVQoGQD[75] - 104))] - (iVQoGQD[135] - 112)] + iVQoGQD[215];
};

High preset

{
  target: "node",
  preset: "high",

  calculator: true,
  compact: true,
  controlFlowFlattening: 0.75,
  deadCode: 0.2,
  dispatcher: true,
  duplicateLiteralsRemoval: 0.75,
  flatten: true,
  globalConcealing: true,
  identifierGenerator: "randomized",
  minify: true,
  movedDeclarations: true,
  objectExtraction: true,
  opaquePredicates: 0.75,
  renameVariables: true,
  renameGlobals: true,
  shuffle: { hash: 0.5, true: 0.5 },
  stack: true,
  stringConcealing: true,
  stringCompression: true,
  stringEncoding: true,
  stringSplitting: 0.75,

  // Use at own risk
  eval: false,
  rgf: false
}

Medium preset

{
  target: "node",
  preset: "medium",

  calculator: true,
  compact: true,
  controlFlowFlattening: 0.5,
  deadCode: 0.025,
  dispatcher: 0.75,
  duplicateLiteralsRemoval: 0.5,
  globalConcealing: true,
  identifierGenerator: "randomized",
  minify: true,
  movedDeclarations: true,
  objectExtraction: true,
  opaquePredicates: 0.5,
  renameVariables: true,
  renameGlobals: true,
  shuffle: true,
  stack: 0.5,
  stringConcealing: true,
  stringSplitting: 0.25
}

Low Preset

{
  target: "node",
  preset: "low",

  calculator: true,
  compact: true,
  controlFlowFlattening: 0.25,
  deadCode: 0.01,
  dispatcher: 0.5,
  duplicateLiteralsRemoval: true,
  identifierGenerator: "randomized",
  minify: true,
  movedDeclarations: true,
  objectExtraction: true,
  opaquePredicates: 0.1,
  renameVariables: true,
  renameGlobals: true,
  stringConcealing: true
}

Locks

You must enable locks yourself, and configure them to your needs.

{
  target: "node",
  lock: {
    integrity: true,
    domainLock: ["mywebsite.com"],
    osLock: ["windows", "linux"],
    browserLock: ["firefox"],
    startDate: new Date("Feb 1 2021"),
    endDate: new Date("Mar 1 2021"),
    antiDebug: true,
    nativeFunctions: true,

    // crashes browser
    countermeasures: true,

    // or custom callback (pre-obfuscated name)
    countermeasures: "onLockDetected"
  }
}

Optional features

These features are experimental or a security concern.

{
  target: "node",
  eval: true, // (security concern)
  rgf: true, // (security concern)

  // set to false for web-related scripts
  renameGlobals: false,

  // experimental
  identifierGenerator: function(){
    return "myvar_" + (counter++);
  }
}

Percentages

Most settings allow percentages to control the frequency of the transformation. Fine-tune the percentages to keep file size down, and performance high.

{
  target: "node",
  controlFlowFlattening: true, // equal to 1, which is 100% (slow)

  controlFlowFlattening: 0.5, // 50%
  controlFlowFlattening: 0.01 // 1%
}

Probabilities

Mix modes using an object with key-value pairs to represent each mode's percentage.

{
  target: "node",
  identifierGenerator: {
    "hexadecimal": 0.25, // 25% each
    "randomized": 0.25,
    "mangled": 0.25,
    "number": 0.25
  },

  shuffle: {hash: 0.5, true: 0.5} // 50% hash, 50% normal
}

Custom Implementations

{
  target: "node",
  
  // avoid renaming a certain variable
  renameVariables: name=>name!="jQuery",

  // custom variable names
  identifierGenerator: ()=>{
    return "_0x" + Math.random().toString(16).slice(2, 8);
  },

  // force encoding on a string
  stringConcealing: (str)=>{
    if (str=="https://mywebsite.com/my-secret-api"){
      return true;
    }

    // 60%
    return Math.random() < 0.6;
  },

  // set limits
  deadCode: ()=>{
    dead++; 

    return dead < 50;
  }
}

Potential Issues

  1. String Encoding can corrupt files. Disable stringEncoding if this happens.
  2. Dead Code can bloat file size. Reduce or disable deadCode.
  3. Rename Globals can break web-scripts. i. Disable renameGlobals or ii. Refactor your code
    // Avoid doing this
var myGlobalFunction = ()=>console.log("Called");

// Do this instead
window.myGlobalFunction = ()=>console.log("Called");

File size and Performance

Obfuscation can bloat file size and negatively impact performance. Avoid using the following:

Option Description
deadCode Bloats file size. Use low percentages.
stringSplitting, stringEncoding Bloats file size. Avoid using these altogether.
controlFlowFlattening Significant performance impact. Use very low percentage when source code is large.
dispatcher Slow performance. Use low percentage.

"The obfuscator broke my code!"

Try disabling features in the following order:

  1. flatten
  2. stack
  3. dispatcher

If the error continues then open an issue.

Bug report

Please open an issue with the code and config used.

Feature request

Please open an issue and be descriptive. Don't submit any PRs until approved.

JsConfuser vs. Javascript-obfuscator

Javascript-obfuscator (https://obfuscator.io) is the popular choice for JS obfuscation. This means more attackers are aware of their strategies. JSConfuser provides unique features and is lesser-known.

Automated deobfuscators are aware of https://obfuscator.io's techniques:

https://www.youtube.com/watch?v=_UIqhaYyCMI

However, the dev is quick to fix these. The one above no longer works.

Alternatively, you could go the paid-route with Jscrambler.com (enterprise only) or PreEmptive.com

I've included several alternative obfuscators in the samples/ folder. They are all derived from the input.js file.

Debugging

Enable logs to view the obfuscator's state.

{
  target: "node",
  verbose: true
}

About the internals

This obfuscator depends on two libraries to work: acorn and escodegen

  • acorn is responsible for parsing source code into an AST.
  • escodegen is responsible for generating source from modified AST.

The tree is modified by transformations, which each traverse the entire tree. Properties starting with $ are for saving information (typically circular data), these properties are deleted before output.