Botan  1.11.10
Public Member Functions | List of all members
Botan::CTR_BE Class Reference

#include <ctr.h>

Inheritance diagram for Botan::CTR_BE:
Botan::StreamCipher Botan::SymmetricAlgorithm

Public Member Functions

void cipher (const byte in[], byte out[], size_t length)
 
void cipher1 (byte buf[], size_t len)
 
void clear ()
 
CTR_BEclone () const
 
 CTR_BE (BlockCipher *cipher)
 
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
 
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
 

Detailed Description

CTR-BE (Counter mode, big-endian)

Definition at line 19 of file ctr.h.

Constructor & Destructor Documentation

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

Definition at line 13 of file ctr.cpp.

13  :
14  m_cipher(ciph),
15  m_counter(256 * m_cipher->block_size()),
16  m_pad(m_counter.size()),
17  m_pad_pos(0)
18  {
19  }

Member Function Documentation

void Botan::CTR_BE::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 42 of file ctr.cpp.

References Botan::xor_buf().

43  {
44  while(length >= m_pad.size() - m_pad_pos)
45  {
46  xor_buf(out, in, &m_pad[m_pad_pos], m_pad.size() - m_pad_pos);
47  length -= (m_pad.size() - m_pad_pos);
48  in += (m_pad.size() - m_pad_pos);
49  out += (m_pad.size() - m_pad_pos);
50  increment_counter();
51  }
52  xor_buf(out, in, &m_pad[m_pad_pos], length);
53  m_pad_pos += length;
54  }
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 34 of file stream_cipher.h.

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

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

Implements Botan::SymmetricAlgorithm.

Definition at line 21 of file ctr.cpp.

References Botan::zeroise().

22  {
23  m_cipher->clear();
24  zeroise(m_pad);
25  zeroise(m_counter);
26  m_pad_pos = 0;
27  }
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:166
CTR_BE* Botan::CTR_BE::clone ( ) const
inlinevirtual

Get a new object representing the same algorithm as *this

Implements Botan::StreamCipher.

Definition at line 36 of file ctr.h.

37  { return new CTR_BE(m_cipher->clone()); }
CTR_BE(BlockCipher *cipher)
Definition: ctr.cpp:13
template<typename Alloc >
void Botan::StreamCipher::decrypt ( std::vector< byte, Alloc > &  inout)
inlineinherited

Definition at line 46 of file stream_cipher.h.

47  { 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 38 of file stream_cipher.h.

39  { 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 42 of file stream_cipher.h.

43  { cipher(&inout[0], &inout[0], inout.size()); }
virtual void cipher(const byte in[], byte out[], size_t len)=0
Key_Length_Specification Botan::CTR_BE::key_spec ( ) const
inlinevirtual
Returns
object describing limits on key size

Implements Botan::SymmetricAlgorithm.

Definition at line 29 of file ctr.h.

30  {
31  return m_cipher->key_spec();
32  }
size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const
inlineinherited
Returns
minimum allowed key length

Definition at line 36 of file sym_algo.h.

Referenced by Botan::PBE_PKCS5v20::PBE_PKCS5v20().

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::CTR_BE::name ( ) const
virtual

Implements Botan::SymmetricAlgorithm.

Definition at line 37 of file ctr.cpp.

Referenced by set_iv().

38  {
39  return ("CTR-BE(" + m_cipher->name() + ")");
40  }
void Botan::CTR_BE::set_iv ( const byte  iv[],
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 56 of file ctr.cpp.

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

57  {
58  if(!valid_iv_length(iv_len))
59  throw Invalid_IV_Length(name(), iv_len);
60 
61  const size_t bs = m_cipher->block_size();
62 
63  zeroise(m_counter);
64 
65  buffer_insert(m_counter, 0, iv, iv_len);
66 
67  // Set m_counter blocks to IV, IV + 1, ... IV + 255
68  for(size_t i = 1; i != 256; ++i)
69  {
70  buffer_insert(m_counter, i*bs, &m_counter[(i-1)*bs], bs);
71 
72  for(size_t j = 0; j != bs; ++j)
73  if(++m_counter[i*bs + (bs - 1 - j)])
74  break;
75  }
76 
77  m_cipher->encrypt_n(&m_counter[0], &m_pad[0], 256);
78  m_pad_pos = 0;
79  }
std::string name() const
Definition: ctr.cpp:37
bool valid_iv_length(size_t iv_len) const
Definition: ctr.h:26
size_t buffer_insert(std::vector< T, Alloc > &buf, size_t buf_offset, const T input[], size_t input_length)
Definition: secmem.h:103
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:166
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_Filter::MAC_Filter(), and Botan::StreamCipher_Filter::StreamCipher_Filter().

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::CTR_BE::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 ctr.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: