Botan: Botan::PKCS5_PBKDF2 Class Reference

Botan 1.10.17

Public Member Functions | List of all members
Botan::PKCS5_PBKDF2 Class Reference

`#include <pbkdf2.h>`

Inheritance diagram for Botan::PKCS5_PBKDF2:

## Public Member Functions
void | clear ()
PBKDF * | clone () const
OctetString | derive_key (size_t output_len, const std::string &passphrase, const byte salt[], size_t salt_len, size_t iterations) const
std::string | name () const
| PKCS5_PBKDF2 (MessageAuthenticationCode *mac_fn)
| ~PKCS5_PBKDF2 ()

## Detailed Description

PKCS #5 PBKDF2

Definition at line 19 of file pbkdf2.h.

## Constructor & Destructor Documentation

## ◆ PKCS5_PBKDF2()

Botan::PKCS5_PBKDF2::PKCS5_PBKDF2 | ( | MessageAuthenticationCode * | mac_fn | ) |
| inline

Create a PKCS #5 instance using the specified message auth code

Parameters

  mac_fn | the MAC to use

Definition at line 41 of file pbkdf2.h.

41 : mac(mac_fn) {}

## ◆ ~PKCS5_PBKDF2()

Botan::PKCS5_PBKDF2::~PKCS5_PBKDF2 | ( |  | ) |
| inline

Destructor

Definition at line 46 of file pbkdf2.h.

46 { delete mac; }

## Member Function Documentation

## ◆ clear()

void Botan::PBKDF::clear | ( |  | ) |
| inlinevirtualinherited

Zeroize internal state

Implements Botan::Algorithm.

Definition at line 30 of file pbkdf.h.

30 {}

## ◆ clone()

PBKDF* Botan::PKCS5_PBKDF2::clone | ( |  | ) | const
| inlinevirtual

Returns
  new instance of this same algorithm

Implements Botan::PBKDF.

Definition at line 27 of file pbkdf2.h.

28 {
29 return new PKCS5_PBKDF2(mac->clone());
30 }
Botan::PKCS5_PBKDF2::PKCS5_PBKDF2
PKCS5_PBKDF2(MessageAuthenticationCode *mac_fn)
Definition: pbkdf2.h:41
Botan::MessageAuthenticationCode::clone
virtual MessageAuthenticationCode * clone() const =0

## ◆ derive_key()

OctetString Botan::PKCS5_PBKDF2::derive_key | ( | size_t | output_len,
|  | const std::string & | passphrase,
|  | const byte | salt[],
|  | size_t | salt_len,
|  | size_t | iterations
| ) |  | const
| virtual

Derive a key from a passphrase

Parameters

  output_len | the desired length of the key to produce
  passphrase | the password to derive the key from
  salt | a randomly chosen salt
  salt_len | length of salt in bytes
  iterations | the number of iterations to use (use 10K or more)

Implements Botan::PBKDF.

Definition at line 17 of file pbkdf2.cpp.

References Botan::Buffered_Computation::final(), name(), Botan::Buffered_Computation::output_length(), Botan::SymmetricAlgorithm::set_key(), Botan::to_string(), Botan::Buffered_Computation::update(), Botan::Buffered_Computation::update_be(), and Botan::xor_buf().

Referenced by Botan::check_passhash9(), and Botan::CryptoBox::decrypt().

21 {
22 if(iterations == 0)
23 throw Invalid_Argument("PKCS#5 PBKDF2: Invalid iteration count");
24
25 try
26 {
27 mac->set_key(reinterpret_cast<const byte*>(passphrase.data()),
28 passphrase.length());
29 }
30 catch(Invalid_Key_Length)
31 {
32 throw Exception(name() + " cannot accept passphrases of length " +
33 to_string(passphrase.length()));
34 }
35
36 SecureVector<byte> key(key_len);
37
38 byte* T = &key[0];
39
40 SecureVector<byte> U(mac->output_length());
41
42 u32bit counter = 1;
43 while(key_len)
44 {
45 size_t T_size = std::min<size_t>(mac->output_length(), key_len);
46
47 mac->update(salt, salt_size);
48 mac->update_be(counter);
49 mac->final(&U[0]);
50
51 xor_buf(T, U, T_size);
52
53 for(size_t j = 1; j != iterations; ++j)
54 {
55 mac->update(U);
56 mac->final(&U[0]);
57 xor_buf(T, U, T_size);
58 }
59
60 key_len -= T_size;
61 T += T_size;
62 ++counter;
63 }
64
65 return key;
66 }
Botan::Invalid_Argument
std::invalid_argument Invalid_Argument
Definition: exceptn.h:20
Botan::PKCS5_PBKDF2::name
std::string name() const
Definition: pbkdf2.h:22
Botan::byte
unsigned char byte
Definition: types.h:22
Botan::SymmetricAlgorithm::set_key
void set_key(const SymmetricKey &key)
Definition: sym_algo.h:60
Botan::Buffered_Computation::update
void update(const byte in[], size_t length)
Definition: buf_comp.h:33
Botan::Exception
std::runtime_error Exception
Definition: exceptn.h:19
Botan::Buffered_Computation::final
void final(byte out[])
Definition: buf_comp.h:80
Botan::to_string
std::string to_string(u64bit n, size_t min_len)
Definition: parsing.cpp:42
Botan::Buffered_Computation::update_be
void update_be(const T in)
Definition: buf_comp.h:48
Botan::xor_buf
void xor_buf(byte out[], const byte in[], size_t length)
Definition: xor_buf.h:21
Botan::Buffered_Computation::output_length
virtual size_t output_length() const =0
Botan::u32bit
unsigned int u32bit
Definition: types.h:32

## ◆ name()

std::string Botan::PKCS5_PBKDF2::name | ( |  | ) | const
| inlinevirtual

Returns
  name of this algorithm

Implements Botan::Algorithm.

Definition at line 22 of file pbkdf2.h.

Referenced by derive_key().

23 {
24 return "PBKDF2(" + mac->name() + ")";
25 }
Botan::MessageAuthenticationCode::name
virtual std::string name() const =0

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

- src/pbkdf/pbkdf2/pbkdf2.h
- src/pbkdf/pbkdf2/pbkdf2.cpp