Add - sm2.doEncrypt()增加入参asn1，默认false，给true使用 asn1 对加密结果进行编码并输出

src/sm2/asn1.js

@@ -78,7 +78,18 @@ class DERInteger extends ASN1Object {
     return this.v
   }
 }
+class DEROctetString extends ASN1Object {
+  constructor(s) {
+    super()
+
+    this.t = '04' // octstr 标签说明
+    if (s) this.v = s.toLowerCase()
+  }
 
+  getValue() {
+    return this.v
+  }
+}
 class DERSequence extends ASN1Object {
   constructor(asn1Array) {
     super()
@@ -134,6 +145,14 @@ module.exports = {
 
     return derSeq.getEncodedHex()
   },
+  encodeEnc(x, y, hash, cipher) {
+    const derX = new DERInteger(x)
+    const derY = new DERInteger(y)
+    const derHash = new DEROctetString(hash)
+    const derCipher = new DEROctetString(cipher)
+    const derSeq = new DERSequence([derX, derY, derHash, derCipher])
+    return derSeq.getEncodedHex()
+  },
 
   /**
    * 解析 ASN.1 der，针对 sm2 验签

src/sm2/index.js

@@ -1,6 +1,6 @@
 /* eslint-disable no-use-before-define */
 const {BigInteger} = require('jsbn')
-const {encodeDer, decodeDer} = require('./asn1')
+const {encodeDer, decodeDer, encodeEnc} = require('./asn1')
 const _ = require('./utils')
 const sm3 = require('./sm3').sm3
 
@@ -10,7 +10,7 @@ const C1C2C3 = 0
 /**
  * 加密
  */
-function doEncrypt(msg, publicKey, cipherMode = 1) {
+function doEncrypt(msg, publicKey, cipherMode = 1, asn1 = false) {
   msg = typeof msg === 'string' ? _.hexToArray(_.utf8ToHex(msg)) : Array.prototype.slice.call(msg)
   publicKey = _.getGlobalCurve().decodePointHex(publicKey) // 先将公钥转成点
 
@@ -50,8 +50,12 @@ function doEncrypt(msg, publicKey, cipherMode = 1) {
     msg[i] ^= t[offset++] & 0xff
   }
   const c2 = _.arrayToHex(msg)
-
-  return cipherMode === C1C2C3 ? c1 + c2 + c3 : c1 + c3 + c2
+  if (asn1) {
+    const { Px, Py } = keypair
+    return cipherMode === C1C2C3 ? encodeEnc(Px, Py, c2, c3) : encodeEnc(Px, Py, c3, c2)
+  } else {
+    return cipherMode === C1C2C3 ? c1 + c2 + c3 : c1 + c3 + c2
+  }
 }
 
 /**

src/sm2/utils.js

@@ -45,7 +45,7 @@ function generateKeyPairHex(a, b, c) {
   const Py = leftPad(P.getY().toBigInteger().toString(16), 64)
   const publicKey = '04' + Px + Py
 
-  return {privateKey, publicKey}
+  return {privateKey, publicKey, Px, Py}
 }
 
 /**