Botan  1.11.32
Public Types | Public Member Functions | Static Public Member Functions | List of all members
Botan::OFB Class Referencefinal

#include <ofb.h>

Inheritance diagram for Botan::OFB:
Botan::StreamCipher Botan::SymmetricAlgorithm

Public Types

typedef SCAN_Name Spec
 

Public Member Functions

void cipher (const byte in[], byte out[], size_t length) override
 
void cipher1 (byte buf[], size_t len)
 
void clear () override
 
OFBclone () const override
 
template<typename Alloc >
void decrypt (std::vector< byte, Alloc > &inout)
 
template<typename Alloc >
void encipher (std::vector< byte, Alloc > &inout)
 
template<typename Alloc >
void encrypt (std::vector< byte, Alloc > &inout)
 
Key_Length_Specification key_spec () const override
 
size_t maximum_keylength () const
 
size_t minimum_keylength () const
 
std::string name () const override
 
 OFB (BlockCipher *cipher)
 
virtual std::string provider () const
 
void seek (u64bit offset) override
 
void set_iv (const byte iv[], size_t iv_len) override
 
void set_key (const SymmetricKey &key)
 
template<typename Alloc >
void set_key (const std::vector< byte, Alloc > &key)
 
void set_key (const byte key[], size_t length)
 
bool valid_iv_length (size_t iv_len) const override
 
bool valid_keylength (size_t length) const
 

Static Public Member Functions

static std::unique_ptr< StreamCiphercreate (const std::string &algo_spec, const std::string &provider="")
 
static OFBmake (const Spec &spec)
 
static std::vector< std::string > providers (const std::string &algo_spec)
 

Detailed Description

Output Feedback Mode

Definition at line 19 of file ofb.h.

Member Typedef Documentation

§ Spec

Definition at line 22 of file stream_cipher.h.

Constructor & Destructor Documentation

§ OFB()

Botan::OFB::OFB ( BlockCipher cipher)
explicit
Parameters
cipherthe underlying block cipher to use

Definition at line 22 of file ofb.cpp.

Referenced by make().

22  :
23  m_cipher(cipher),
24  m_buffer(m_cipher->block_size()),
25  m_buf_pos(0)
26  {
27  }
void cipher(const byte in[], byte out[], size_t length) override
Definition: ofb.cpp:49

Member Function Documentation

§ cipher()

void Botan::OFB::cipher ( const byte  in[],
byte  out[],
size_t  len 
)
overridevirtual

Encrypt or decrypt a message

Parameters
inthe plaintext
outthe byte array to hold the output, i.e. the ciphertext
lenthe length of both in and out in bytes

Implements Botan::StreamCipher.

Definition at line 49 of file ofb.cpp.

References Botan::xor_buf().

50  {
51  while(length >= m_buffer.size() - m_buf_pos)
52  {
53  xor_buf(out, in, &m_buffer[m_buf_pos], m_buffer.size() - m_buf_pos);
54  length -= (m_buffer.size() - m_buf_pos);
55  in += (m_buffer.size() - m_buf_pos);
56  out += (m_buffer.size() - m_buf_pos);
57  m_cipher->encrypt(m_buffer);
58  m_buf_pos = 0;
59  }
60  xor_buf(out, in, &m_buffer[m_buf_pos], length);
61  m_buf_pos += length;
62  }
void xor_buf(T out[], const T in[], size_t length)
Definition: mem_ops.h:90

§ cipher1()

void Botan::StreamCipher::cipher1 ( byte  buf[],
size_t  len 
)
inlineinherited

Encrypt or decrypt a message

Parameters
bufthe plaintext / ciphertext
lenthe length of buf in bytes

Definition at line 50 of file stream_cipher.h.

Referenced by Botan::SIV_Encryption::finish().

51  { cipher(buf, buf, len); }
virtual void cipher(const byte in[], byte out[], size_t len)=0

§ clear()

void Botan::OFB::clear ( )
overridevirtual

Implements Botan::SymmetricAlgorithm.

Definition at line 29 of file ofb.cpp.

References set_iv(), and Botan::zeroise().

30  {
31  m_cipher->clear();
32  zeroise(m_buffer);
33  m_buf_pos = 0;
34  }
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:194

§ clone()

OFB* Botan::OFB::clone ( ) const
inlineoverridevirtual

Get a new object representing the same algorithm as *this

Implements Botan::StreamCipher.

Definition at line 36 of file ofb.h.

37  { return new OFB(m_cipher->clone()); }
OFB(BlockCipher *cipher)
Definition: ofb.cpp:22

§ create()

std::unique_ptr< StreamCipher > Botan::StreamCipher::create ( const std::string &  algo_spec,
const std::string &  provider = "" 
)
staticinherited

Create an instance based on a name Will return a null pointer if the algo/provider combination cannot be found. If provider is empty then best available is chosen.

Definition at line 33 of file stream_cipher.cpp.

References Botan::StreamCipher::provider().

Referenced by Botan::get_cipher_mode(), Botan::get_stream_cipher(), Botan::Lion::make(), and Botan::make_stream_cipher().

35  {
36  return std::unique_ptr<StreamCipher>(make_a<StreamCipher>(Botan::StreamCipher::Spec(algo_spec), provider));
37  }
virtual std::string provider() const
Definition: stream_cipher.h:93

§ decrypt()

template<typename Alloc >
void Botan::StreamCipher::decrypt ( std::vector< byte, Alloc > &  inout)
inlineinherited

Definition at line 62 of file stream_cipher.h.

63  { cipher(inout.data(), inout.data(), inout.size()); }
virtual void cipher(const byte in[], byte out[], size_t len)=0

§ encipher()

template<typename Alloc >
void Botan::StreamCipher::encipher ( std::vector< byte, Alloc > &  inout)
inlineinherited

Definition at line 54 of file stream_cipher.h.

55  { cipher(inout.data(), inout.data(), inout.size()); }
virtual void cipher(const byte in[], byte out[], size_t len)=0

§ encrypt()

template<typename Alloc >
void Botan::StreamCipher::encrypt ( std::vector< byte, Alloc > &  inout)
inlineinherited

Definition at line 58 of file stream_cipher.h.

59  { cipher(inout.data(), inout.data(), inout.size()); }
virtual void cipher(const byte in[], byte out[], size_t len)=0

§ key_spec()

Key_Length_Specification Botan::OFB::key_spec ( ) const
inlineoverridevirtual
Returns
object describing limits on key size

Implements Botan::SymmetricAlgorithm.

Definition at line 29 of file ofb.h.

30  {
31  return m_cipher->key_spec();
32  }

§ make()

OFB * Botan::OFB::make ( const Spec spec)
static

Definition at line 12 of file ofb.cpp.

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_count(), Botan::BlockCipher::create(), and OFB().

Referenced by Botan::StreamCipher::~StreamCipher().

13  {
14  if(spec.algo_name() == "OFB" && spec.arg_count() == 1)
15  {
16  if(auto c = BlockCipher::create(spec.arg(0)))
17  return new OFB(c.release());
18  }
19  return nullptr;
20  }
static std::unique_ptr< BlockCipher > create(const std::string &algo_spec, const std::string &provider="")
OFB(BlockCipher *cipher)
Definition: ofb.cpp:22

§ maximum_keylength()

size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const
inlineinherited
Returns
minimum allowed key length

Definition at line 36 of file sym_algo.h.

37  {
38  return key_spec().maximum_keylength();
39  }
size_t maximum_keylength() const
Definition: key_spec.h:69
virtual Key_Length_Specification key_spec() const =0

§ minimum_keylength()

size_t Botan::SymmetricAlgorithm::minimum_keylength ( ) const
inlineinherited
Returns
maxmium allowed key length

Definition at line 44 of file sym_algo.h.

45  {
46  return key_spec().minimum_keylength();
47  }
virtual Key_Length_Specification key_spec() const =0
size_t minimum_keylength() const
Definition: key_spec.h:61

§ name()

std::string Botan::OFB::name ( ) const
overridevirtual

Implements Botan::SymmetricAlgorithm.

Definition at line 44 of file ofb.cpp.

Referenced by set_iv().

45  {
46  return "OFB(" + m_cipher->name() + ")";
47  }

§ provider()

virtual std::string Botan::StreamCipher::provider ( ) const
inlinevirtualinherited
Returns
provider information about this implementation. Default is "base", might also return "sse2", "avx2", "openssl", or some other arbitrary string.

Reimplemented in Botan::ChaCha.

Definition at line 93 of file stream_cipher.h.

Referenced by Botan::StreamCipher::create().

93 { return "base"; }

§ providers()

std::vector< std::string > Botan::StreamCipher::providers ( const std::string &  algo_spec)
staticinherited

Returns the list of available providers for this algorithm, empty if not available

Definition at line 39 of file stream_cipher.cpp.

Referenced by Botan::TLS::Ciphersuite::by_id(), and Botan::get_stream_cipher_providers().

40  {
41  return providers_of<StreamCipher>(StreamCipher::Spec(algo_spec));
42  }

§ seek()

void Botan::OFB::seek ( u64bit  offset)
overridevirtual

Set the offset and the state used later to generate the keystream

Parameters
offsetthe offset where we begin to generate the keystream

Implements Botan::StreamCipher.

Definition at line 77 of file ofb.cpp.

78  {
79  throw Exception("OFB does not support seeking");
80  }

§ set_iv()

void Botan::OFB::set_iv ( const byte  [],
size_t  iv_len 
)
overridevirtual

Resync the cipher using the IV

Parameters
ivthe initialization vector
iv_lenthe length of the IV in bytes

Implements Botan::StreamCipher.

Definition at line 64 of file ofb.cpp.

References Botan::buffer_insert(), name(), valid_iv_length(), and Botan::zeroise().

Referenced by clear().

65  {
66  if(!valid_iv_length(iv_len))
67  throw Invalid_IV_Length(name(), iv_len);
68 
69  zeroise(m_buffer);
70  buffer_insert(m_buffer, 0, iv, iv_len);
71 
72  m_cipher->encrypt(m_buffer);
73  m_buf_pos = 0;
74  }
bool valid_iv_length(size_t iv_len) const override
Definition: ofb.h:26
std::string name() const override
Definition: ofb.cpp:44
size_t buffer_insert(std::vector< T, Alloc > &buf, size_t buf_offset, const T input[], size_t input_length)
Definition: secmem.h:116
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:194

§ set_key() [1/3]

void Botan::SymmetricAlgorithm::set_key ( const SymmetricKey key)
inlineinherited

Set the symmetric key of this object.

Parameters
keythe SymmetricKey to be set.

Definition at line 63 of file sym_algo.h.

References Botan::OctetString::begin(), and Botan::OctetString::length().

Referenced by Botan::aont_package(), Botan::aont_unpackage(), botan_mac_set_key(), Botan::GOST_34_11::clear(), Botan::DESX::decrypt_n(), Botan::pbkdf2(), and Botan::TLS_PRF::TLS_PRF().

64  {
65  set_key(key.begin(), key.length());
66  }
void set_key(const SymmetricKey &key)
Definition: sym_algo.h:63

§ set_key() [2/3]

template<typename Alloc >
void Botan::SymmetricAlgorithm::set_key ( const std::vector< byte, Alloc > &  key)
inlineinherited

Definition at line 69 of file sym_algo.h.

70  {
71  set_key(key.data(), key.size());
72  }
void set_key(const SymmetricKey &key)
Definition: sym_algo.h:63

§ set_key() [3/3]

void Botan::SymmetricAlgorithm::set_key ( const byte  key[],
size_t  length 
)
inlineinherited

Set the symmetric key of this object.

Parameters
keythe to be set as a byte array.
lengthin bytes of key param

Definition at line 79 of file sym_algo.h.

80  {
81  if(!valid_keylength(length))
82  throw Invalid_Key_Length(name(), length);
83  key_schedule(key, length);
84  }
bool valid_keylength(size_t length) const
Definition: sym_algo.h:54
virtual std::string name() const =0

§ valid_iv_length()

bool Botan::OFB::valid_iv_length ( size_t  iv_len) const
inlineoverridevirtual
Parameters
iv_lenthe length of the IV in bytes
Returns
if the length is valid for this algorithm

Reimplemented from Botan::StreamCipher.

Definition at line 26 of file ofb.h.

Referenced by set_iv().

27  { return (iv_len <= m_cipher->block_size()); }

§ valid_keylength()

bool Botan::SymmetricAlgorithm::valid_keylength ( size_t  length) const
inlineinherited

Check whether a given key length is valid for this algorithm.

Parameters
lengththe key length to be checked.
Returns
true if the key length is valid.

Definition at line 54 of file sym_algo.h.

Referenced by Botan::aont_package(), and Botan::aont_unpackage().

55  {
56  return key_spec().valid_keylength(length);
57  }
bool valid_keylength(size_t length) const
Definition: key_spec.h:51
virtual Key_Length_Specification key_spec() const =0

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