Botan  1.11.15
Public Types | Public Member Functions | Static Public Member Functions | List of all members
Botan::OFB Class Reference

#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)
 
void cipher1 (byte buf[], size_t len)
 
void clear ()
 
OFBclone () const
 
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
 
size_t maximum_keylength () const
 
size_t minimum_keylength () const
 
std::string name () const
 
 OFB (BlockCipher *cipher)
 
void set_iv (const byte iv[], size_t iv_len)
 
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
 
bool valid_keylength (size_t length) const
 

Static Public Member Functions

static OFBmake (const Spec &spec)
 

Detailed Description

Output Feedback Mode

Definition at line 19 of file ofb.h.

Member Typedef Documentation

Definition at line 73 of file stream_cipher.h.

Constructor & Destructor Documentation

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

Definition at line 25 of file ofb.cpp.

Referenced by make().

25  :
26  m_cipher(cipher),
27  m_buffer(m_cipher->block_size()),
28  m_buf_pos(0)
29  {
30  }
void cipher(const byte in[], byte out[], size_t length)
Definition: ofb.cpp:52

Member Function Documentation

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

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 52 of file ofb.cpp.

References Botan::xor_buf().

53  {
54  while(length >= m_buffer.size() - m_buf_pos)
55  {
56  xor_buf(out, in, &m_buffer[m_buf_pos], m_buffer.size() - m_buf_pos);
57  length -= (m_buffer.size() - m_buf_pos);
58  in += (m_buffer.size() - m_buf_pos);
59  out += (m_buffer.size() - m_buf_pos);
60  m_cipher->encrypt(m_buffer);
61  m_buf_pos = 0;
62  }
63  xor_buf(out, in, &m_buffer[m_buf_pos], length);
64  m_buf_pos += length;
65  }
void xor_buf(T out[], const T in[], size_t length)
Definition: xor_buf.h:23
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 36 of file stream_cipher.h.

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

37  { cipher(buf, buf, len); }
virtual void cipher(const byte in[], byte out[], size_t len)=0
void Botan::OFB::clear ( )
virtual

Implements Botan::SymmetricAlgorithm.

Definition at line 32 of file ofb.cpp.

References Botan::zeroise().

33  {
34  m_cipher->clear();
35  zeroise(m_buffer);
36  m_buf_pos = 0;
37  }
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:168
OFB* Botan::OFB::clone ( ) const
inlinevirtual

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:25
template<typename Alloc >
void Botan::StreamCipher::decrypt ( std::vector< byte, Alloc > &  inout)
inlineinherited

Definition at line 48 of file stream_cipher.h.

49  { cipher(&inout[0], &inout[0], inout.size()); }
virtual void cipher(const byte in[], byte out[], size_t len)=0
template<typename Alloc >
void Botan::StreamCipher::encipher ( std::vector< byte, Alloc > &  inout)
inlineinherited

Definition at line 40 of file stream_cipher.h.

41  { cipher(&inout[0], &inout[0], inout.size()); }
virtual void cipher(const byte in[], byte out[], size_t len)=0
template<typename Alloc >
void Botan::StreamCipher::encrypt ( std::vector< byte, Alloc > &  inout)
inlineinherited

Definition at line 44 of file stream_cipher.h.

45  { cipher(&inout[0], &inout[0], inout.size()); }
virtual void cipher(const byte in[], byte out[], size_t len)=0
Key_Length_Specification Botan::OFB::key_spec ( ) const
inlinevirtual
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  }
OFB * Botan::OFB::make ( const Spec spec)
static

Definition at line 15 of file ofb.cpp.

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_count(), c, Botan::get_block_cipher(), and OFB().

16  {
17  if(spec.algo_name() == "OFB" && spec.arg_count() == 1)
18  {
19  if(BlockCipher* c = get_block_cipher(spec.arg(0)))
20  return new OFB(c);
21  }
22  return nullptr;
23  }
BlockCipher * get_block_cipher(const std::string &algo_spec, const std::string &provider)
Definition: lookup.cpp:27
const BigInt & c
Definition: rsa.cpp:109
OFB(BlockCipher *cipher)
Definition: ofb.cpp:25
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
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  }
size_t minimum_keylength() const
Definition: key_spec.h:61
virtual Key_Length_Specification key_spec() const =0
std::string Botan::OFB::name ( ) const
virtual

Implements Botan::SymmetricAlgorithm.

Definition at line 47 of file ofb.cpp.

Referenced by set_iv().

48  {
49  return "OFB(" + m_cipher->name() + ")";
50  }
void Botan::OFB::set_iv ( const byte  [],
size_t  iv_len 
)
virtual

Resync the cipher using the IV

Parameters
ivthe initialization vector
iv_lenthe length of the IV in bytes

Reimplemented from Botan::StreamCipher.

Definition at line 67 of file ofb.cpp.

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

68  {
69  if(!valid_iv_length(iv_len))
70  throw Invalid_IV_Length(name(), iv_len);
71 
72  zeroise(m_buffer);
73  buffer_insert(m_buffer, 0, iv, iv_len);
74 
75  m_cipher->encrypt(m_buffer);
76  m_buf_pos = 0;
77  }
std::string name() const
Definition: ofb.cpp:47
size_t buffer_insert(std::vector< T, Alloc > &buf, size_t buf_offset, const T input[], size_t input_length)
Definition: secmem.h:105
bool valid_iv_length(size_t iv_len) const
Definition: ofb.h:26
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:168
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::TLS::Session::decrypt(), Botan::TLS::Session::encrypt(), and Botan::pbkdf2().

64  {
65  set_key(key.begin(), key.length());
66  }
void set_key(const SymmetricKey &key)
Definition: sym_algo.h:63
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[0], key.size());
72  }
void set_key(const SymmetricKey &key)
Definition: sym_algo.h:63
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
bool Botan::OFB::valid_iv_length ( size_t  iv_len) const
inlinevirtual
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()); }
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: