Botan::RFC4880_S2K Class Reference

#include <pgp_s2k.h>

Inheritance diagram for Botan::RFC4880_S2K:

Public Member Functions
void	derive_key (uint8_t out[], size_t out_len, const char *password, size_t password_len, const uint8_t salt[], size_t salt_len) const override
virtual void	derive_key (uint8_t out[], size_t out_len, const char *password, size_t password_len, const uint8_t salt[], size_t salt_len, const uint8_t ad[], size_t ad_len, const uint8_t key[], size_t key_len) const
void	hash (std::span< uint8_t > out, std::string_view password, std::span< const uint8_t > salt) const
void	hash (std::span< uint8_t > out, std::string_view password, std::span< const uint8_t > salt, std::span< const uint8_t > associated_data, std::span< const uint8_t > key) const
size_t	iterations () const override
virtual size_t	memory_param () const
virtual size_t	parallelism () const
	RFC4880_S2K (std::unique_ptr< HashFunction > hash, size_t iterations)
virtual bool	supports_associated_data () const
virtual bool	supports_keyed_operation () const
std::string	to_string () const override
virtual size_t	total_memory_usage () const

Detailed Description

OpenPGP's S2K

See RFC 4880 sections 3.7.1.1, 3.7.1.2, and 3.7.1.3 If the salt is empty and iterations == 1, "simple" S2K is used If the salt is non-empty and iterations == 1, "salted" S2K is used If the salt is non-empty and iterations > 1, "iterated" S2K is used

Note that unlike PBKDF2, OpenPGP S2K's "iterations" are defined as the number of bytes hashed.

Definition at line 80 of file pgp_s2k.h.

Constructor & Destructor Documentation

RFC4880_S2K()

Botan::RFC4880_S2K::RFC4880_S2K	(	std::unique_ptr< HashFunction >	hash,
		size_t	iterations )

Parameters

hash	the hash function to use
iterations	is rounded due to PGP formatting

Definition at line 128 of file pgp_s2k.cpp.

                                                                            :
      m_hash(std::move(hash)), m_iterations(iterations) {}

Member Function Documentation

derive_key() [1/2]

void Botan::RFC4880_S2K::derive_key ( uint8_t out[], size_t out_len, const char * password, size_t password_len, const uint8_t salt[], size_t salt_len ) const

overridevirtual

Derive a key from a password

Parameters

out	buffer to store the derived key, must be of out_len bytes
out_len	the desired length of the key to produce
password	the password to derive the key from
password_len	the length of password in bytes
salt	a randomly chosen salt
salt_len	length of salt in bytes

This function is const, but is not thread safe. Different threads should either use unique objects, or serialize all access.

Implements Botan::PasswordHash.

Definition at line 135 of file pgp_s2k.cpp.

                                                    {
   pgp_s2k(*m_hash, out, out_len, password, password_len, salt, salt_len, m_iterations);
}

derive_key() [2/2]

void Botan::PasswordHash::derive_key ( uint8_t out[], size_t out_len, const char * password, size_t password_len, const uint8_t salt[], size_t salt_len, const uint8_t ad[], size_t ad_len, const uint8_t key[], size_t key_len ) const

virtualinherited

Derive a key from a password plus additional data and/or a secret key

Currently this is only supported for Argon2. Using a non-empty AD or key with other algorithms will cause a Not_Implemented exception.

Parameters

out	buffer to store the derived key, must be of out_len bytes
out_len	the desired length of the key to produce
password	the password to derive the key from
password_len	the length of password in bytes
salt	a randomly chosen salt
salt_len	length of salt in bytes
ad	some additional data
ad_len	length of ad in bytes
key	a secret key
key_len	length of key in bytes

This function is const, but is not thread safe. Different threads should either use unique objects, or serialize all access.

Reimplemented in Botan::Argon2.

Definition at line 34 of file pwdhash.cpp.

                                                    {
   BOTAN_UNUSED(ad, key);
 
   if(ad_len == 0 && key_len == 0) {
      return this->derive_key(out, out_len, password, password_len, salt, salt_len);
   } else {
      throw Not_Implemented("PasswordHash " + this->to_string() + " does not support AD or key");
   }
}

References BOTAN_UNUSED, Botan::PasswordHash::derive_key(), and Botan::PasswordHash::to_string().

hash() [1/2]

void Botan::PasswordHash::hash ( std::span< uint8_t > out, std::string_view password, std::span< const uint8_t > salt ) const

inlineinherited

Hash a password into a bitstring

Parameters

out	a span where the derived key will be placed
password	the password to derive the key from
salt	a randomly chosen salt

This function is const, but is not thread safe. Different threads should either use unique objects, or serialize all access.

Definition at line 81 of file pwdhash.h.

                                                                                                  {
         this->derive_key(out.data(), out.size(), password.data(), password.size(), salt.data(), salt.size());
      }

hash() [2/2]

void Botan::PasswordHash::hash ( std::span< uint8_t > out, std::string_view password, std::span< const uint8_t > salt, std::span< const uint8_t > associated_data, std::span< const uint8_t > key ) const

inlineinherited

Hash a password into a bitstring

Parameters

out	a span where the derived key will be placed
password	the password to derive the key from
salt	a randomly chosen salt
associated_data	some additional data
key	a secret key

This function is const, but is not thread safe. Different threads should either use unique objects, or serialize all access.

Definition at line 97 of file pwdhash.h.

                                                  {
         this->derive_key(out.data(),
                          out.size(),
                          password.data(),
                          password.size(),
                          salt.data(),
                          salt.size(),
                          associated_data.data(),
                          associated_data.size(),
                          key.data(),
                          key.size());
      }

iterations()

size_t Botan::RFC4880_S2K::iterations ( ) const

inlineoverridevirtual

Most password hashes have some notion of iterations.

Implements Botan::PasswordHash.

Definition at line 90 of file pgp_s2k.h.

{ return m_iterations; }

memory_param()

virtual size_t Botan::PasswordHash::memory_param ( ) const

inlinevirtualinherited

Some password hashing algorithms have a parameter which controls how much memory is used. If not supported by some algorithm, returns 0.

Reimplemented in Botan::Argon2, Botan::Bcrypt_PBKDF, and Botan::Scrypt.

Definition at line 40 of file pwdhash.h.

{ return 0; }

parallelism()

virtual size_t Botan::PasswordHash::parallelism ( ) const

inlinevirtualinherited

Some password hashing algorithms have a parallelism parameter. If the algorithm does not support this notion, then the function returns zero. This allows distinguishing between a password hash which just does not support parallel operation, vs one that does support parallel operation but which has been configured to use a single lane.

Reimplemented in Botan::Argon2, Botan::Bcrypt_PBKDF, and Botan::Scrypt.

Definition at line 50 of file pwdhash.h.

{ return 0; }

supports_associated_data()

virtual bool Botan::PasswordHash::supports_associated_data ( ) const

inlinevirtualinherited

Returns true if this password hash supports supplying associated data

Reimplemented in Botan::Argon2.

Definition at line 69 of file pwdhash.h.

{ return false; }

supports_keyed_operation()

virtual bool Botan::PasswordHash::supports_keyed_operation ( ) const

inlinevirtualinherited

Returns true if this password hash supports supplying a key

Reimplemented in Botan::Argon2.

Definition at line 64 of file pwdhash.h.

{ return false; }

to_string()

std::string Botan::RFC4880_S2K::to_string ( ) const

overridevirtual

Implements Botan::PasswordHash.

Definition at line 131 of file pgp_s2k.cpp.

                                       {
   return fmt("OpenPGP-S2K({},{})", m_hash->name(), m_iterations);
}

References Botan::fmt().

total_memory_usage()

virtual size_t Botan::PasswordHash::total_memory_usage ( ) const

inlinevirtualinherited

Returns an estimate of the total number of bytes required to perform this key derivation.

If this algorithm uses a small and constant amount of memory, with no effort made towards being memory hard, this function returns 0.

Reimplemented in Botan::Argon2, Botan::Bcrypt_PBKDF, and Botan::Scrypt.

Definition at line 59 of file pwdhash.h.

{ return 0; }

---

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

• src/lib/pbkdf/pgp_s2k/pgp_s2k.h
• src/lib/pbkdf/pgp_s2k/pgp_s2k.cpp