Botan::TOTP Class Reference

#include <totp.h>

Public Member Functions
uint32_t	generate_totp (std::chrono::system_clock::time_point time_point)
uint32_t	generate_totp (uint64_t unix_time)
	TOTP (const SymmetricKey &key, const std::string &hash_algo="SHA-1", size_t digits=6, size_t time_step=30)
	TOTP (const uint8_t key[], size_t key_len, const std::string &hash_algo="SHA-1", size_t digits=6, size_t time_step=30)
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)

Detailed Description

TOTP (time based) one time passwords (RFC 6238)

Definition at line 18 of file totp.h.

Constructor & Destructor Documentation

Botan::TOTP::TOTP ( const SymmetricKey &  key, const std::string &  hash_algo = "SHA-1", size_t  digits = 6, size_t  time_step = 30  )

inline

Parameters

key	the secret key shared between client and server
hash_algo	the hash algorithm to use, should be SHA-1, SHA-256 or SHA-512
digits	the number of digits in the OTP (must be 6, 7, or 8)
time_step	granularity of OTP in seconds

Definition at line 27 of file totp.h.

                                                     :
         TOTP(key.begin(), key.size(), hash_algo, digits, time_step) {}

Botan::TOTP::TOTP	(	const uint8_t	key[],
		size_t	key_len,
		const std::string &	hash_algo = "SHA-1",
		size_t	digits = 6,
		size_t	time_step = 30
	)

Parameters

key	the secret key shared between client and server
key_len	length of key
hash_algo	the hash algorithm to use, should be SHA-1, SHA-256 or SHA-512
digits	the number of digits in the OTP (must be 6, 7, or 8)
time_step	granularity of OTP in seconds

Definition at line 13 of file totp.cpp.

References BOTAN_ARG_CHECK.

   : m_hotp(key, key_len, hash_algo, digits)
   , m_time_step(time_step)
   , m_unix_epoch(calendar_point(1970, 1, 1, 0, 0, 0).to_std_timepoint())
   {
   /*
   * Technically any time step except 0 is valid, but 30 is typical
   * and over 5 minutes seems unlikely.
   */
   BOTAN_ARG_CHECK(m_time_step > 0 && m_time_step < 300, "Invalid TOTP time step");
   }

Member Function Documentation

uint32_t Botan::TOTP::generate_totp

(

std::chrono::system_clock::time_point

time_point

)

Convert the provided time_point to a Unix timestamp and call generate_totp

Definition at line 27 of file totp.cpp.

Referenced by botan_totp_generate().

   {
   const uint64_t unix_time =
      std::chrono::duration_cast<std::chrono::seconds>(current_time - m_unix_epoch).count();
   return this->generate_totp(unix_time);
   }

uint32_t Botan::TOTP::generate_totp

(

uint64_t

unix_time

)

Generate the OTP corresponding the the provided "Unix timestamp" (ie number of seconds since midnight Jan 1, 1970)

Definition at line 34 of file totp.cpp.

References Botan::HOTP::generate_hotp().

   {
   return m_hotp.generate_hotp(unix_time / m_time_step);
   }

bool Botan::TOTP::verify_totp	(	uint32_t	otp,
		std::chrono::system_clock::time_point	time,
		size_t	clock_drift_accepted = 0
	)

Definition at line 39 of file totp.cpp.

Referenced by botan_totp_check().

   {
   const uint64_t unix_time =
      std::chrono::duration_cast<std::chrono::seconds>(current_time - m_unix_epoch).count();
   return verify_totp(otp, unix_time, clock_drift_accepted);
   }

bool Botan::TOTP::verify_totp	(	uint32_t	otp,
		uint64_t	unix_time,
		size_t	clock_drift_accepted = 0
	)

Definition at line 47 of file totp.cpp.

References Botan::HOTP::generate_hotp().

   {
   uint64_t t = unix_time / m_time_step;

   for(size_t i = 0; i <= clock_drift_accepted; ++i)
      {
      if(m_hotp.generate_hotp(t-i) == otp)
         {
         return true;
         }
      }

   return false;
   }

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The documentation for this class was generated from the following files:

• src/lib/misc/hotp/totp.h
• src/lib/misc/hotp/totp.cpp