asn1-parser/asn1-parser.min.js

An ASN.1 parser in less than 100 lines of Vanilla JavaScript, part of the Bluecrypt suite.

(function(exports){"use strict";if(!exports.ASN1){exports.ASN1={}}if(!exports.Enc){exports.Enc={}}if(!exports.PEM){exports.PEM={}}var ASN1=exports.ASN1;var Enc=exports.Enc;var PEM=exports.PEM;ASN1.ELOOPN=102;ASN1.ELOOP="uASN1.js Error: iterated over "+ASN1.ELOOPN+"+ elements (probably a malformed file)";ASN1.EDEEPN=60;ASN1.EDEEP="uASN1.js Error: element nested "+ASN1.EDEEPN+"+ layers deep (probably a malformed file)";ASN1.CTYPES=[48,49,160,161];ASN1.VTYPES=[1,2,5,6,12,130];ASN1.parse=function parseAsn1Helper(buf){function parseAsn1(buf,depth,eager){if(depth.length>=ASN1.EDEEPN){throw new Error(ASN1.EDEEP)}var index=2;var asn1={type:buf[0],lengthSize:0,length:buf[1]};var child;var iters=0;var adjust=0;var adjustedLen;if(128&asn1.length){asn1.lengthSize=127&asn1.length;asn1.length=parseInt(Enc.bufToHex(buf.slice(index,index+asn1.lengthSize)),16);index+=asn1.lengthSize}if(0===buf[index]&&(2===asn1.type||3===asn1.type)){if(asn1.length>1){index+=1;adjust=-1}}adjustedLen=asn1.length+adjust;function parseChildren(eager){asn1.children=[];while(iters<ASN1.ELOOPN&&index<2+asn1.length+asn1.lengthSize){iters+=1;depth.length+=1;child=parseAsn1(buf.slice(index,index+adjustedLen),depth,eager);depth.length-=1;index+=2+child.lengthSize+child.length;if(index>2+asn1.lengthSize+asn1.length){if(!eager){console.error(JSON.stringify(asn1,ASN1._replacer,2))}throw new Error("Parse error: child value length ("+child.length+") is greater than remaining parent length ("+(asn1.length-index)+" = "+asn1.length+" - "+index+")")}asn1.children.push(child)}if(index!==2+asn1.lengthSize+asn1.length){throw new Error("premature end-of-file")}if(iters>=ASN1.ELOOPN){throw new Error(ASN1.ELOOP)}delete asn1.value;return asn1}if(-1!==ASN1.CTYPES.indexOf(asn1.type)){return parseChildren(eager)}asn1.value=buf.slice(index,index+adjustedLen);if(-1!==ASN1.VTYPES.indexOf(asn1.type)){return asn1}try{return parseChildren(true)}catch(e){asn1.children.length=0;return asn1}}var asn1=parseAsn1(buf,[]);var len=buf.byteLength||buf.length;if(len!==2+asn1.lengthSize+asn1.length){throw new Error("Length of buffer does not match length of ASN.1 sequence.")}return asn1};ASN1._replacer=function(k,v){if("type"===k){return"0x"+Enc.numToHex(v)}if(v&&"value"===k){return"0x"+Enc.bufToHex(v.data||v)}return v};PEM.parseBlock=PEM.parseBlock||function(str){var der=str.split(/\n/).filter(function(line){return!/-----/.test(line)}).join("");return{der:Enc.base64ToBuf(der)}};Enc.base64ToBuf=function(b64){return Enc.binToBuf(atob(b64))};Enc.binToBuf=function(bin){var arr=bin.split("").map(function(ch){return ch.charCodeAt(0)});return"undefined"!==typeof Uint8Array?new Uint8Array(arr):arr};Enc.bufToHex=function(u8){var hex=[];var i,h;var len=u8.byteLength||u8.length;for(i=0;i<len;i+=1){h=u8[i].toString(16);if(h.length%2){h="0"+h}hex.push(h)}return hex.join("").toLowerCase()};Enc.numToHex=function(d){d=d.toString(16);if(d.length%2){return"0"+d}return d}})("undefined"!==typeof window?window:module.exports);