#include <otp.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, std::string_view hash_algo="SHA-1", size_t digits=6, size_t time_step=30)

	TOTP (const uint8_t key[], size_t key_len, std::string_view 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 63 of file otp.h.

Constructor & Destructor Documentation

◆ TOTP() [1/2]

Botan::TOTP::TOTP	(	const SymmetricKey &	key,
		std::string_view	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 71 of file otp.h.

71 :

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

Botan::TOTP::TOTP

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

Definition otp.h:71

◆ TOTP() [2/2]

Botan::TOTP::TOTP	(	const uint8_t	key[],
		size_t	key_len,
		std::string_view	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 14 of file totp.cpp.

                                                                                                         :
      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");
}

References BOTAN_ARG_CHECK.

Member Function Documentation

◆ generate_totp() [1/2]

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 25 of file totp.cpp.

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

References generate_totp().

Referenced by generate_totp().

◆ generate_totp() [2/2]

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 30 of file totp.cpp.

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

References Botan::HOTP::generate_hotp().

◆ verify_totp() [1/2]

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

Definition at line 34 of file totp.cpp.

                                                                                                              {
   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);
}

References verify_totp().

Referenced by verify_totp().

◆ verify_totp() [2/2]

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

Definition at line 39 of file totp.cpp.

                                                                                    {
   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;
}