162 lines
3.7 KiB
JavaScript
Executable File
162 lines
3.7 KiB
JavaScript
Executable File
/* eslint-disable class-methods-use-this */
|
||
const {BigInteger} = require('jsbn')
|
||
|
||
function bigintToValue(bigint) {
|
||
let h = bigint.toString(16)
|
||
if (h[0] !== '-') {
|
||
// 正数
|
||
if (h.length % 2 === 1) h = '0' + h // 补齐到整字节
|
||
else if (!h.match(/^[0-7]/)) h = '00' + h // 非0开头，则补一个全0字节
|
||
} else {
|
||
// 负数
|
||
h = h.substr(1)
|
||
|
||
let len = h.length
|
||
if (len % 2 === 1) len += 1 // 补齐到整字节
|
||
else if (!h.match(/^[0-7]/)) len += 2 // 非0开头，则补一个全0字节
|
||
|
||
let mask = ''
|
||
for (let i = 0; i < len; i++) mask += 'f'
|
||
mask = new BigInteger(mask, 16)
|
||
|
||
// 对绝对值取反，加1
|
||
h = mask.xor(bigint).add(BigInteger.ONE)
|
||
h = h.toString(16).replace(/^-/, '')
|
||
}
|
||
return h
|
||
}
|
||
|
||
class ASN1Object {
|
||
constructor() {
|
||
this.tlv = null
|
||
this.t = '00'
|
||
this.l = '00'
|
||
this.v = ''
|
||
}
|
||
|
||
/**
|
||
* 获取 der 编码比特流16进制串
|
||
*/
|
||
getEncodedHex() {
|
||
if (!this.tlv) {
|
||
this.v = this.getValue()
|
||
this.l = this.getLength()
|
||
this.tlv = this.t + this.l + this.v
|
||
}
|
||
return this.tlv
|
||
}
|
||
|
||
getLength() {
|
||
const n = this.v.length / 2 // 字节数
|
||
let nHex = n.toString(16)
|
||
if (nHex.length % 2 === 1) nHex = '0' + nHex // 补齐到整字节
|
||
|
||
if (n < 128) {
|
||
// 短格式，以 0 开头
|
||
return nHex
|
||
} else {
|
||
// 长格式，以 1 开头
|
||
const head = 128 + nHex.length / 2 // 1(1位) + 真正的长度占用字节数(7位) + 真正的长度
|
||
return head.toString(16) + nHex
|
||
}
|
||
}
|
||
|
||
getValue() {
|
||
return ''
|
||
}
|
||
}
|
||
|
||
class DERInteger extends ASN1Object {
|
||
constructor(bigint) {
|
||
super()
|
||
|
||
this.t = '02' // 整型标签说明
|
||
if (bigint) this.v = bigintToValue(bigint)
|
||
}
|
||
|
||
getValue() {
|
||
return this.v
|
||
}
|
||
}
|
||
|
||
class DERSequence extends ASN1Object {
|
||
constructor(asn1Array) {
|
||
super()
|
||
|
||
this.t = '30' // 序列标签说明
|
||
this.asn1Array = asn1Array
|
||
}
|
||
|
||
getValue() {
|
||
this.v = this.asn1Array.map(asn1Object => asn1Object.getEncodedHex()).join('')
|
||
return this.v
|
||
}
|
||
}
|
||
|
||
/**
|
||
* 获取 l 占用字节数
|
||
*/
|
||
function getLenOfL(str, start) {
|
||
if (+str[start + 2] < 8) return 1 // l 以0开头，则表示短格式，只占一个字节
|
||
return +str.substr(start + 2, 2) & 0x7f + 1 // 长格式，取第一个字节后7位作为长度真正占用字节数，再加上本身
|
||
}
|
||
|
||
/**
|
||
* 获取 l
|
||
*/
|
||
function getL(str, start) {
|
||
// 获取 l
|
||
const len = getLenOfL(str, start)
|
||
const l = str.substr(start + 2, len * 2)
|
||
|
||
if (!l) return -1
|
||
const bigint = +l[0] < 8 ? new BigInteger(l, 16) : new BigInteger(l.substr(2), 16)
|
||
|
||
return bigint.intValue()
|
||
}
|
||
|
||
/**
|
||
* 获取 v 的位置
|
||
*/
|
||
function getStartOfV(str, start) {
|
||
const len = getLenOfL(str, start)
|
||
return start + (len + 1) * 2
|
||
}
|
||
|
||
module.exports = {
|
||
/**
|
||
* ASN.1 der 编码，针对 sm2 签名
|
||
*/
|
||
encodeDer(r, s) {
|
||
const derR = new DERInteger(r)
|
||
const derS = new DERInteger(s)
|
||
const derSeq = new DERSequence([derR, derS])
|
||
|
||
return derSeq.getEncodedHex()
|
||
},
|
||
|
||
/**
|
||
* 解析 ASN.1 der，针对 sm2 验签
|
||
*/
|
||
decodeDer(input) {
|
||
// 结构：
|
||
// input = | tSeq | lSeq | vSeq |
|
||
// vSeq = | tR | lR | vR | tS | lS | vS |
|
||
const start = getStartOfV(input, 0)
|
||
|
||
const vIndexR = getStartOfV(input, start)
|
||
const lR = getL(input, start)
|
||
const vR = input.substr(vIndexR, lR * 2)
|
||
|
||
const nextStart = vIndexR + vR.length
|
||
const vIndexS = getStartOfV(input, nextStart)
|
||
const lS = getL(input, nextStart)
|
||
const vS = input.substr(vIndexS, lS * 2)
|
||
|
||
const r = new BigInteger(vR, 16)
|
||
const s = new BigInteger(vS, 16)
|
||
|
||
return {r, s}
|
||
}
|
||
}
|