1 files changed, 56 insertions, 0 deletions
diff --git a/src/lib/misc/hotp/totp.h b/src/lib/misc/hotp/totp.h
new file mode 100644
index 000000000..767c7cc5a
--- /dev/null
+++ b/src/lib/misc/hotp/totp.h
@@ -0,0 +1,56 @@
+/*
+* (C) 2017 Jack Lloyd
+*
+* Botan is released under the Simplified BSD License (see license.txt)
+*/
+
+#ifndef BOTAN_TOTP_H__
+#define BOTAN_TOTP_H__
+
+#include <botan/hotp.h>
+#include <chrono>
+
+namespace Botan {
+
+/**
+* TOTP (time based) one time passwords (RFC 6238)
+*/
+class BOTAN_DLL TOTP
+   {
+   public:
+      /**
+      * @param key the secret key shared between client and server
+      * @param hash_algo the hash algorithm to use, should be SHA-1, SHA-256 or SHA-512
+      * @param digits the number of digits in the OTP (must be 6, 7, or 8)
+      * @param time_step granularity of OTP in seconds
+      */
+      TOTP(const SymmetricKey& key, const std::string& hash_algo = "SHA-1",
+           size_t digits = 6, size_t time_step = 30);
+
+      /**
+      * Convert the provided time_point to a Unix timestamp and call generate_totp
+      */
+      uint32_t generate_totp(std::chrono::system_clock::time_point time_point);
+
+      /**
+      * Generate the OTP cooresponding the the provided "Unix timestamp" (ie
+      * number of seconds since midnight Jan 1, 1970)
+      */
+      uint32_t generate_totp(uint64_t unix_time);
+
+      bool verify_totp(uint32_t otp,
+                       std::chrono::system_clock::time_point time,
+                       size_t clock_drift_accepted = 0);
+
+      bool verify_totp(uint32_t otp, uint64_t unix_time,
+                       size_t clock_drift_accepted = 0);
+
+   private:
+      HOTP m_hotp;
+      size_t m_time_step;
+      std::chrono::system_clock::time_point m_unix_epoch;
+   };
+
+}
+
+#endif