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/*
* PBKDF
* (C) 1999-2007,2012,2015 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_PBKDF_H_
#define BOTAN_PBKDF_H_
#include <botan/symkey.h>
#include <botan/exceptn.h>
#include <chrono>
namespace Botan {
/**
* Base class for PBKDF (password based key derivation function)
* implementations. Converts a password into a key using a salt
* and iterated hashing to make brute force attacks harder.
*/
class BOTAN_PUBLIC_API(2,0) PBKDF
{
public:
/**
* Create an instance based on a name
* If provider is empty then best available is chosen.
* @param algo_spec algorithm name
* @param provider provider implementation to choose
* @return a null pointer if the algo/provider combination cannot be found
*/
static std::unique_ptr<PBKDF> create(const std::string& algo_spec,
const std::string& provider = "");
/**
* @return list of available providers for this algorithm, empty if not available
*/
static std::vector<std::string> providers(const std::string& algo_spec);
/**
* @return new instance of this same algorithm
*/
virtual PBKDF* clone() const = 0;
/**
* @return name of this PBKDF
*/
virtual std::string name() const = 0;
virtual ~PBKDF() = default;
/**
* Derive a key from a passphrase for a number of iterations
* specified by either iterations or if iterations == 0 then
* running until msec time has elapsed.
*
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param iterations the number of iterations to use (use 10K or more)
* @param msec if iterations is zero, then instead the PBKDF is
* run until msec milliseconds has passed.
* @return the number of iterations performed
*/
virtual size_t pbkdf(uint8_t out[], size_t out_len,
const std::string& passphrase,
const uint8_t salt[], size_t salt_len,
size_t iterations,
std::chrono::milliseconds msec) const = 0;
/**
* Derive a key from a passphrase for a number of iterations.
*
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param iterations the number of iterations to use (use 10K or more)
*/
void pbkdf_iterations(uint8_t out[], size_t out_len,
const std::string& passphrase,
const uint8_t salt[], size_t salt_len,
size_t iterations) const;
/**
* Derive a key from a passphrase, running until msec time has elapsed.
*
* @param out buffer to store the derived key, must be of out_len bytes
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param msec if iterations is zero, then instead the PBKDF is
* run until msec milliseconds has passed.
* @param iterations set to the number iterations executed
*/
void pbkdf_timed(uint8_t out[], size_t out_len,
const std::string& passphrase,
const uint8_t salt[], size_t salt_len,
std::chrono::milliseconds msec,
size_t& iterations) const;
/**
* Derive a key from a passphrase for a number of iterations.
*
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param iterations the number of iterations to use (use 10K or more)
* @return the derived key
*/
secure_vector<uint8_t> pbkdf_iterations(size_t out_len,
const std::string& passphrase,
const uint8_t salt[], size_t salt_len,
size_t iterations) const;
/**
* Derive a key from a passphrase, running until msec time has elapsed.
*
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param msec if iterations is zero, then instead the PBKDF is
* run until msec milliseconds has passed.
* @param iterations set to the number iterations executed
* @return the derived key
*/
secure_vector<uint8_t> pbkdf_timed(size_t out_len,
const std::string& passphrase,
const uint8_t salt[], size_t salt_len,
std::chrono::milliseconds msec,
size_t& iterations) const;
// Following kept for compat with 1.10:
/**
* Derive a key from a passphrase
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param iterations the number of iterations to use (use 10K or more)
*/
OctetString derive_key(size_t out_len,
const std::string& passphrase,
const uint8_t salt[], size_t salt_len,
size_t iterations) const
{
return pbkdf_iterations(out_len, passphrase, salt, salt_len, iterations);
}
/**
* Derive a key from a passphrase
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param iterations the number of iterations to use (use 10K or more)
*/
template<typename Alloc>
OctetString derive_key(size_t out_len,
const std::string& passphrase,
const std::vector<uint8_t, Alloc>& salt,
size_t iterations) const
{
return pbkdf_iterations(out_len, passphrase, salt.data(), salt.size(), iterations);
}
/**
* Derive a key from a passphrase
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param salt_len length of salt in bytes
* @param msec is how long to run the PBKDF
* @param iterations is set to the number of iterations used
*/
OctetString derive_key(size_t out_len,
const std::string& passphrase,
const uint8_t salt[], size_t salt_len,
std::chrono::milliseconds msec,
size_t& iterations) const
{
return pbkdf_timed(out_len, passphrase, salt, salt_len, msec, iterations);
}
/**
* Derive a key from a passphrase using a certain amount of time
* @param out_len the desired length of the key to produce
* @param passphrase the password to derive the key from
* @param salt a randomly chosen salt
* @param msec is how long to run the PBKDF
* @param iterations is set to the number of iterations used
*/
template<typename Alloc>
OctetString derive_key(size_t out_len,
const std::string& passphrase,
const std::vector<uint8_t, Alloc>& salt,
std::chrono::milliseconds msec,
size_t& iterations) const
{
return pbkdf_timed(out_len, passphrase, salt.data(), salt.size(), msec, iterations);
}
};
/**
* Password based key derivation function factory method
* @param algo_spec the name of the desired PBKDF algorithm
* @param provider the provider to use
* @return pointer to newly allocated object of that type
*/
inline PBKDF* get_pbkdf(const std::string& algo_spec,
const std::string& provider = "")
{
std::unique_ptr<PBKDF> p(PBKDF::create(algo_spec, provider));
if(p)
return p.release();
throw Algorithm_Not_Found(algo_spec);
}
}
#endif
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