coolaj86/ecdsa-csr.js
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ASN.1 cleanup (comments)

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This commit is contained in:
AJ ONeal 2018-11-18 16:35:53 -07:00
parent 4b8f32a871
commit 3657d674ab
1 changed files with 33 additions and 24 deletions
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57
lib/ecdsacsr.js
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@ -6,49 +6,58 @@ var crypto = require('crypto');
// prime256v1 (ANSI X9.62 named elliptic curve)
var OBJ_ID_EC = '06 08 2A8648CE3D030107'.replace(/\s+/g, '').toLowerCase();
function ASN1() {
//
// A dumbed-down, minimal ASN.1 packer
//
// Almost every ASN.1 type that's important for CSR
// can be represented generically with only a few rules.
function ASN1(/*type, hexstrings...*/) {
var args = Array.prototype.slice.call(arguments);
var typ = args.shift();
var str = args.join('').replace(/\s+/g, '');
var str = args.join('').replace(/\s+/g, '').toLowerCase();
var len = (str.length/2);
var len2 = len;
var lenlen = 0;
var hex = typ;
var hlen = '';
// high-order bit means multiple bytes
if (len2 !== Math.round(len2)) {
// We can't have an odd number of hex chars
if (len !== Math.round(len)) {
throw new Error("invalid hex");
}
if (len2 > 127) {
// The first byte of any ASN.1 sequence is the type (Sequence, Integer, etc)
// The second byte is either the size of the value, or the size of its size
// 1. If the second byte is < 0x80 (128) it is considered the size
// 2. If it is > 0x80 then it describes the number of bytes of the size
// ex: 0x82 means the next 2 bytes describe the size of the value
// 3. The special case of exactly 0x80 is "indefinite" length (to end-of-file)
if (len > 127) {
lenlen += 1;
while (len2 > 255) {
while (len > 255) {
lenlen += 1;
len2 = len2 >> 8;
//console.warn("LEN2", len2);
len = len >> 8;
}
}
if (lenlen) {
hlen = numToHex(0x80 + lenlen);
}
/*
console.warn(
'typ:', typ
, 'lenlen:', hlen
, 'len:', len, numToHex(len)
);
console.warn('str:', str);
*/
return hex + hlen + numToHex(len) + str;
if (lenlen) { hex += numToHex(0x80 + lenlen); }
return hex + numToHex(str.length/2) + str;
}
// The Integer type has some special rules
ASN1.UInt = function UINT() {
var str = Array.prototype.slice.call(arguments).join('');
var first = parseInt(str.slice(0, 2), 16);
// high-order bit means signed, negative
// we want positive, so we pad with a leading '00'
// If the first byte is 0x80 or greater, the number is considered negative
// Therefore we add a '00' prefix if the 0x80 bit is set
if (0x80 & first) { str = '00' + str; }
return ASN1('02', str);
};
// The Bit String type also has a special rule
ASN1.BitStr = function BITSTR() {
var str = Array.prototype.slice.call(arguments).join('');
// '00' is a mask of how many bits of the next byte to ignore