diff --git a/ndn-cpp/c/util/time.c b/ndn-cpp/c/util/time.c
index 41047f8..7ffa517 100644
--- a/ndn-cpp/c/util/time.c
+++ b/ndn-cpp/c/util/time.c
@@ -34,3 +34,23 @@
   sprintf(isoString, "%04d%02d%02dT%02d%02d%02d%s", 1900 + gmt->tm_year, gmt->tm_mon + 1, gmt->tm_mday,
     gmt->tm_hour, gmt->tm_min, gmt->tm_sec, fraction);
 }
+
+ndn_MillisecondsSince1970
+ndn_fromIsoString(const char* isoString)
+{
+  // Initialize time zone, etc.
+  time_t dummyTime = 0;
+  struct tm time = *gmtime(&dummyTime);
+  
+  sscanf(isoString, "%4d%2d%2dT%2d%2d", &time.tm_year, &time.tm_mon, &time.tm_mday, &time.tm_hour, &time.tm_min);
+  // Skip the time past minutes and get the float seconds.
+  double seconds;
+  sscanf(isoString + (4 + 2 + 2 + 1 + 2 + 2), "%lf", &seconds);
+  
+  // tm_year starts from 1900.
+  time.tm_year -= 1900;
+  // tm_mon starts from 0, not 1.
+  time.tm_mon -= 1;
+  time.tm_sec = 0;
+  return (timegm(&time) + seconds) * 1000.0;  
+}
\ No newline at end of file
diff --git a/ndn-cpp/c/util/time.h b/ndn-cpp/c/util/time.h
index 454216e..b2414c7 100644
--- a/ndn-cpp/c/util/time.h
+++ b/ndn-cpp/c/util/time.h
@@ -21,13 +21,21 @@
 ndn_getNowMilliseconds();
 
 /**
- * Convert the time from milliseconds to ISO time, for example "20131018T184138.423355".
+ * Convert the time from milliseconds to an ISO time string, for example "20131018T184138.423355".
  * @param milliseconds The time in milliseconds since 1/1/1970, including fractions of a millisecond.
  * @param isoString A buffer of at least 23 bytes to receive the null-terminated ISO time string.
  */
 void
 ndn_toIsoString(ndn_MillisecondsSince1970 time, char *isoString);
 
+/**
+ * Parse the ISO time string and return the time in milliseconds.
+ * @param isoString The ISO time string, for example "20131018T184138.423355".
+ * @return The time in milliseconds since 1/1/1970, including fractions of a millisecond.
+ */
+ndn_MillisecondsSince1970
+ndn_fromIsoString(const char* isoString);
+
 #ifdef  __cplusplus
 }
 #endif
diff --git a/ndn-cpp/encoding/der/der.cpp b/ndn-cpp/encoding/der/der.cpp
index 125b9a4..9d3258c 100644
--- a/ndn-cpp/encoding/der/der.cpp
+++ b/ndn-cpp/encoding/der/der.cpp
@@ -6,9 +6,6 @@
  * See COPYING for copyright and distribution information.
  */
 
-#if 1 // TODO: Remove this when we don't throw "not implemented".
-#include <stdexcept>
-#endif
 #include "der-exception.hpp"
 #include "../../util/logging.hpp"
 #include "../../c/util/time.h"
@@ -604,9 +601,7 @@
 
 MillisecondsSince1970 DerGtime::fromIsoString(const string& isoString)
 {
-#if 1
-  throw std::runtime_error("not implemented");
-#endif
+  return ndn_fromIsoString(isoString.c_str());
 }
 
 } // der