diff --git a/phpseclib/File/ASN1.php b/phpseclib/File/ASN1.php
index e5c219b1..12392c2f 100644
--- a/phpseclib/File/ASN1.php
+++ b/phpseclib/File/ASN1.php
@@ -739,7 +739,14 @@ abstract class ASN1
                 return isset(self::$oids[$decoded['content']]) ? self::$oids[$decoded['content']] : $decoded['content'];
             case self::TYPE_UTC_TIME:
             case self::TYPE_GENERALIZED_TIME:
-                if (isset($mapping['implicit'])) {
+                // for explicitly tagged optional stuff
+                if (is_array($decoded['content'])) {
+                    $decoded['content'] = $decoded['content'][0]['content'];
+                }
+                // for implicitly tagged optional stuff
+                // in theory, doing isset($mapping['implicit']) would work but malformed certs do exist
+                // in the wild that OpenSSL decodes without issue so we'll support them as well
+                if (!is_object($decoded['content'])) {
                     $decoded['content'] = self::decodeTime($decoded['content'], $decoded['type']);
                 }
                 return $decoded['content'] ? $decoded['content']->format(self::$format) : false;
diff --git a/phpseclib/File/ASN1/Maps/SubjectInfoAccessSyntax.php b/phpseclib/File/ASN1/Maps/SubjectInfoAccessSyntax.php
new file mode 100644
index 00000000..c395ca1a
--- /dev/null
+++ b/phpseclib/File/ASN1/Maps/SubjectInfoAccessSyntax.php
@@ -0,0 +1,35 @@
+<?php
+
+/**
+ * SubjectInfoAccessSyntax
+ *
+ * PHP version 5
+ *
+ * @category  File
+ * @package   ASN1
+ * @author    Jim Wigginton <terrafrost@php.net>
+ * @copyright 2016 Jim Wigginton
+ * @license   http://www.opensource.org/licenses/mit-license.html  MIT License
+ * @link      http://phpseclib.sourceforge.net
+ */
+
+namespace phpseclib\File\ASN1\Maps;
+
+use phpseclib\File\ASN1;
+
+/**
+ * SubjectInfoAccessSyntax
+ *
+ * @package ASN1
+ * @author  Jim Wigginton <terrafrost@php.net>
+ * @access  public
+ */
+abstract class SubjectInfoAccessSyntax
+{
+    const MAP = [
+        'type'     => ASN1::TYPE_SEQUENCE,
+        'min'      => 1,
+        'max'      => -1,
+        'children' => AccessDescription::MAP
+    ];
+}
diff --git a/tests/Unit/File/ASN1Test.php b/tests/Unit/File/ASN1Test.php
index baa9242b..ce64c112 100644
--- a/tests/Unit/File/ASN1Test.php
+++ b/tests/Unit/File/ASN1Test.php
@@ -364,4 +364,32 @@ class Unit_File_ASN1Test extends PhpseclibTestCase
         $this->assertSame(pack('H*', '6983f09da7ebcfdee0c7a1a7b2c0948cc8f9d776'), $new);
         $this->assertSame($orig, ASN1::decodeOID($new));
     }
+
+    /**
+     * @group github1388
+     */
+    public function testExplicitImplicitDate()
+    {
+        $map = [
+            'type'     => ASN1::TYPE_SEQUENCE,
+            'children' => [
+                'notBefore' => [
+                                             'constant' => 0,
+                                             'optional' => true,
+                                             'implicit' => true,
+                                             'type' => ASN1::TYPE_GENERALIZED_TIME],
+                'notAfter'  => [
+                                             'constant' => 1,
+                                             'optional' => true,
+                                             'implicit' => true,
+                                             'type' => ASN1::TYPE_GENERALIZED_TIME]
+            ]
+        ];
+
+        $a = pack('H*', '3026a011180f32303137303432313039303535305aa111180f32303138303432313230353935395a');
+        $a = ASN1::decodeBER($a);
+        $a = ASN1::asn1map($a[0], $map);
+
+        $this->assertInternalType('array', $a);
+    }
 }