der: support negative integers

indutny · Jul 25, 2019 · 4e61ada · 4e61ada
1 parent 48811c6
commit 4e61ada
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Showing 2 changed files with 4 additions and 4 deletions.
diff --git a/lib/asn1/decoders/der.js b/lib/asn1/decoders/der.js
@@ -253,7 +253,7 @@ DERNode.prototype._decodeBool = function decodeBool(buffer) {
 DERNode.prototype._decodeInt = function decodeInt(buffer, values) {
   // Bigint, return as it is (assume big endian)
   const raw = buffer.raw();
-  let res = new bignum(raw);
+  let res = new bignum(raw).fromTwos(raw.length * 8);
 
   if (values)
     res = values[res.toString(10)] || res;

diff --git a/lib/asn1/encoders/der.js b/lib/asn1/encoders/der.js
@@ -199,9 +199,9 @@ DERNode.prototype._encodeInt = function encodeInt(num, values) {
     if (!BN.isBN(num)) {
       num = new BN(num);
     }
-    const numArray = num.toArray();
-    if (!num.sign && numArray[0] & 0x80) {
-      numArray.unshift(0);
+    const numArray = num.toTwos(num.byteLength() * 8).toArray();
+    if (num.isNeg() !== Boolean(numArray[0] & 0x80)) {
+      numArray.unshift(num.isNeg() ? 0xff : 0);
     }
     num = new Buffer(numArray);
   }