diff --git a/asn1.js b/asn1.js
index 87376c8..bbcc3c0 100644
--- a/asn1.js
+++ b/asn1.js
@@ -72,7 +72,7 @@ class Stream {
         if (pos === undefined)
             pos = this.pos++;
         if (pos >= this.enc.length)
-            throw 'Requesting byte offset ' + pos + ' on a stream of length ' + this.enc.length;
+            throw new Error('Requesting byte offset ' + pos + ' on a stream of length ' + this.enc.length);
         return (typeof this.enc == 'string') ? this.enc.charCodeAt(pos) : this.enc[pos];
     }
     hexByte(b) {
@@ -190,7 +190,7 @@ class Stream {
         let s = this.parseStringISO(start, end).str,
             m = (shortYear ? reTimeS : reTimeL).exec(s);
         if (!m)
-            return 'Unrecognized time: ' + s;
+            throw new Error('Unrecognized time: ' + s);
         if (shortYear) {
             // to avoid querying the timer, use the fixed range [1970, 2069]
             // it will conform with ITU X.400 [-10, +40] sliding window until 2030
@@ -245,7 +245,7 @@ class Stream {
     parseBitString(start, end, maxLength) {
         let unusedBits = this.get(start);
         if (unusedBits > 7)
-            throw 'Invalid BitString with unusedBits=' + unusedBits;
+            throw new Error('Invalid BitString with unusedBits=' + unusedBits);
         let lenBit = ((end - start - 1) << 3) - unusedBits,
             s = '';
         for (let i = start + 1; i < end; ++i) {
@@ -368,7 +368,7 @@ class ASN1Tag {
 
 export class ASN1 {
     constructor(stream, header, length, tag, tagLen, sub) {
-        if (!(tag instanceof ASN1Tag)) throw 'Invalid tag value.';
+        if (!(tag instanceof ASN1Tag)) throw new Error('Invalid tag value.');
         this.stream = stream;
         this.header = header;
         this.length = length;
@@ -531,7 +531,7 @@ export class ASN1 {
         if (len === 0) // long form with length 0 is a special case
             return null; // undefined length
         if (len > 6) // no reason to use Int10, as it would be a huge buffer anyways
-            throw 'Length over 48 bits not supported at position ' + (stream.pos - 1);
+            throw new Error('Length over 48 bits not supported at position ' + (stream.pos - 1));
         buf = 0;
         for (let i = 0; i < len; ++i)
             buf = (buf * 256) + stream.get();
@@ -539,7 +539,7 @@ export class ASN1 {
     }
     static decode(stream, offset, type = ASN1) {
         if (!(type == ASN1 || type.prototype instanceof ASN1))
-            throw 'Must pass a class that extends ASN1';
+            throw new Error('Must pass a class that extends ASN1');
         if (!(stream instanceof Stream))
             stream = new Stream(stream, offset || 0);
         let streamStart = new Stream(stream),
@@ -555,11 +555,11 @@ export class ASN1 {
                     // definite length
                     let end = start + len;
                     if (end > stream.enc.length)
-                        throw 'Container at offset ' + start +  ' has a length of ' + len + ', which is past the end of the stream';
+                        throw new Error('Container at offset ' + start +  ' has a length of ' + len + ', which is past the end of the stream');
                     while (stream.pos < end)
                         sub[sub.length] = type.decode(stream);
                     if (stream.pos != end)
-                        throw 'Content size is not correct for container at offset ' + start;
+                        throw new Error('Content size is not correct for container at offset ' + start);
                 } else {
                     // undefined length
                     try {
@@ -571,7 +571,7 @@ export class ASN1 {
                         }
                         len = start - stream.pos; // undefined lengths are represented as negative values
                     } catch (e) {
-                        throw 'Exception while decoding undefined length content at offset ' + start + ': ' + e;
+                        throw new Error('Exception while decoding undefined length content at offset ' + start + ': ' + e);
                     }
                 }
             };
@@ -583,11 +583,17 @@ export class ASN1 {
             try {
                 if (tag.tagNumber == 0x03)
                     if (stream.get() != 0)
-                        throw 'BIT STRINGs with unused bits cannot encapsulate.';
+                        throw new Error('BIT STRINGs with unused bits cannot encapsulate.');
                 getSub();
-                for (let i = 0; i < sub.length; ++i)
-                    if (sub[i].tag.isEOC())
-                        throw 'EOC is not supposed to be actual content.';
+                for (let s of sub) {
+                    if (s.tag.isEOC())
+                        throw new Error('EOC is not supposed to be actual content.');
+                    try {
+                        s.content();
+                    } catch (e) {
+                        throw new Error('Unable to parse content: ' + e);
+                    }
+                }
             } catch (e) {
                 // but silently ignore when they don't
                 sub = null;
@@ -596,7 +602,7 @@ export class ASN1 {
         }
         if (sub === null) {
             if (len === null)
-                throw "We can't skip over an invalid tag with undefined length at offset " + start;
+                throw new Error("We can't skip over an invalid tag with undefined length at offset " + start);
             stream.pos = start + Math.abs(len);
         }
         return new type(streamStart, header, len, tag, tagLen, sub);
diff --git a/dom.js b/dom.js
index 26f3260..8ccf4ea 100644
--- a/dom.js
+++ b/dom.js
@@ -75,7 +75,12 @@ export class ASN1DOM extends ASN1 {
             }
         }
         head.appendChild(DOM.text(typeName));
-        let content = this.content(contentLength);
+        let content;
+        try {
+            content = this.content(contentLength);
+        } catch (e) {
+            content = 'Cannot decode: ' + e;
+        }
         let oid;
         if (content !== null) {
             let preview = DOM.tag('span', 'preview'),
diff --git a/test.js b/test.js
index cd20b71..884125a 100755
--- a/test.js
+++ b/test.js
@@ -36,7 +36,7 @@ const tests = [
     ['170D3931303530363233343534305A', '1991-05-06 23:45:40 UTC', 'ntop, utc time: UTC'],
     ['17113931303530363136343534302D30373030', '1991-05-06 16:45:40 UTC-07:00', 'ntop, utc time: PDT'],
     // inspired by http://luca.ntop.org/Teaching/Appunti/asn1.html
-    ['0304086E5DC0', 'Exception:\nInvalid BitString with unusedBits=8', 'bit string: invalid unusedBits'],
+    ['0304086E5DC0', 'Exception:\nError: Invalid BitString with unusedBits=8', 'bit string: invalid unusedBits'],
     // http://msdn.microsoft.com/en-us/library/windows/desktop/aa379076(v=vs.85).aspx
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
         '(3 elem)', 'PKCS#10 request'],
@@ -86,6 +86,8 @@ const tests = [
     ['0420041EE4E3B7ED350CC24D034E436D9A1CB15BB1E328D37062FB82E84618AB0A3C', '(32 byte)\n041EE4E3B7ED350CC24D034E436D9A1CB15BB1E328D37062FB82E84618AB0A3C', 'Do not mix encapsulated and structured octet strings'], // GitHub issue #47
     ['181531393835313130363231303632372E332D31323334', '1985-11-06 21:06:27.3 UTC-12:34', 'UTC offsets with minutes'], // GitHub issue #54
     ['181331393835313130363231303632372E332B3134', '1985-11-06 21:06:27.3 UTC+14:00', 'UTC offset +13 and +14'], // GitHub issue #54
+    ['032100171E83C1B251803F86DD01E9CFA886BE89A7316D8372649AC2231EC669F81A84', n => { if (n.sub != null) return 'Should not decode content: ' + n.sub[0].content(); }, 'Key that resembles an UTCTime'], // GitHub issue #79
+    ['171E83C1B251803F86DD01E9CFA886BE89A7316D8372649AC2231EC669F81A84', /^Exception:\nError: Unrecognized time: /, 'Invalid UTCTime'], // GitHub issue #79
 ];
 
 let
@@ -95,24 +97,28 @@ let
 tests.forEach(function (t) {
     const input = t[0],
         expected = t[1],
-        comment = t[2],
-        errorReason = t[3];
+        comment = t[2];
     let result;
     try {
-        result = ASN1.decode(Hex.decode(input)).content();
+        let node = ASN1.decode(Hex.decode(input));
+        if (typeof expected == 'function')
+            result = expected(node);
+        else
+            result = node.content();
         //TODO: check structure, not only first level content
     } catch (e) {
         result = 'Exception:\n' + e;
     }
+    if (expected instanceof RegExp)
+        result = expected.test(result) ? null : 'does not match';
     ++run;
-    if (result == expected) {
+    if (!result || result == expected) {
         if (all) console.log('\x1B[1m\x1B[32mOK \x1B[39m\x1B[22m ' + comment);
-    } else if (errorReason) {
-        ++expErr;
-        console.log('\x1B[1m\x1B[33mEXP\x1B[39m\x1B[22m ' + comment + ' (' + errorReason + ')' + '\n' + result);
     } else {
         ++error;
-        console.log('\x1B[1m\x1B[31mERR\x1B[39m\x1B[22m ' + comment + '\n' + result);
+        console.log('\x1B[1m\x1B[31mERR\x1B[39m\x1B[22m ' + comment);
+        console.log('  \x1B[1m\x1B[34mEXP\x1B[39m\x1B[22m ' + expected.toString().replace(/\n/g, '\n      '));
+        console.log('  \x1B[1m\x1B[33mGOT\x1B[39m\x1B[22m ' + result.replace(/\n/g, '\n      '));
     }
 });
 console.log(run + ' tested, ' + expErr + ' expected, ' + error + ' errors.');