diff --git a/asn1.js b/asn1.js
index 0a87025..b707a71 100644
--- a/asn1.js
+++ b/asn1.js
@@ -246,14 +246,14 @@ Stream.prototype.parseOID = function (start, end, maxLength) {
     return s;
 };
 
-function ASN1(stream, header, length, tag, sub, tlen) {
+function ASN1(stream, header, length, tag, tagLen, sub) {
     if (!(tag instanceof ASN1Tag)) throw 'Invalid tag value.';
     this.stream = stream;
     this.header = header;
     this.length = length;
     this.tag = tag;
+    this.tagLen = tagLen;
     this.sub = sub;
-    this.tlen = tlen;
 }
 ASN1.prototype.typeName = function () {
     switch (this.tag.tagClass) {
@@ -383,9 +383,10 @@ ASN1.prototype.posContent = function () {
 ASN1.prototype.posEnd = function () {
     return this.stream.pos + this.header + Math.abs(this.length);
 };
+/** Position of the length. */
 ASN1.prototype.posLen = function() {
-    return this.stream.pos + this.tlen;
-}
+    return this.stream.pos + this.tagLen;
+};
 ASN1.prototype.toHexString = function () {
     return this.stream.hexDump(this.posStart(), this.posEnd(), true);
 };
@@ -431,7 +432,7 @@ ASN1.decode = function (stream) {
         stream = new Stream(stream, 0);
     var streamStart = new Stream(stream),
         tag = new ASN1Tag(stream),
-        tlen = stream.pos - streamStart.pos,
+        tagLen = stream.pos - streamStart.pos,
         len = ASN1.decodeLength(stream),
         start = stream.pos,
         header = start - streamStart.pos,
@@ -486,7 +487,7 @@ ASN1.decode = function (stream) {
             throw "We can't skip over an invalid tag with undefined length at offset " + start;
         stream.pos = start + Math.abs(len);
     }
-    return new ASN1(streamStart, header, len, tag, sub, tlen);
+    return new ASN1(streamStart, header, len, tag, tagLen, sub);
 };
 
 // export globals