Botan  1.11.15
Public Types | Public Member Functions | Static Public Member Functions
Botan::CTR_BE Class Reference

#include <ctr.h>

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

List of all members.

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 ()
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

Static Public Member Functions

static CTR_BEmake (const Spec &spec)

Detailed Description

CTR-BE (Counter mode, big-endian)

Definition at line 19 of file ctr.h.


Member Typedef Documentation

typedef SCAN_Name Botan::StreamCipher::Spec [inherited]

Definition at line 73 of file stream_cipher.h.


Constructor & Destructor Documentation

Parameters:
cipherthe underlying block cipher to use

Definition at line 25 of file ctr.cpp.

Referenced by make().

                                :
   m_cipher(ciph),
   m_counter(m_cipher->parallel_bytes()),
   m_pad(m_counter.size()),
   m_pad_pos(0)
   {
   }

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 54 of file ctr.cpp.

References Botan::xor_buf().

   {
   while(length >= m_pad.size() - m_pad_pos)
      {
      xor_buf(out, in, &m_pad[m_pad_pos], m_pad.size() - m_pad_pos);
      length -= (m_pad.size() - m_pad_pos);
      in += (m_pad.size() - m_pad_pos);
      out += (m_pad.size() - m_pad_pos);
      increment_counter();
      }
   xor_buf(out, in, &m_pad[m_pad_pos], length);
   m_pad_pos += length;
   }
void Botan::StreamCipher::cipher1 ( byte  buf[],
size_t  len 
) [inline, inherited]

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().

         { cipher(buf, buf, len); }
void Botan::CTR_BE::clear ( ) [virtual]

Implements Botan::SymmetricAlgorithm.

Definition at line 33 of file ctr.cpp.

References Botan::zeroise().

   {
   m_cipher->clear();
   zeroise(m_pad);
   zeroise(m_counter);
   m_pad_pos = 0;
   }
CTR_BE* Botan::CTR_BE::clone ( ) const [inline, virtual]

Get a new object representing the same algorithm as *this

Implements Botan::StreamCipher.

Definition at line 36 of file ctr.h.

         { return new CTR_BE(m_cipher->clone()); }
template<typename Alloc >
void Botan::StreamCipher::decrypt ( std::vector< byte, Alloc > &  inout) [inline, inherited]

Definition at line 48 of file stream_cipher.h.

         { cipher(&inout[0], &inout[0], inout.size()); }
template<typename Alloc >
void Botan::StreamCipher::encipher ( std::vector< byte, Alloc > &  inout) [inline, inherited]

Definition at line 40 of file stream_cipher.h.

         { cipher(&inout[0], &inout[0], inout.size()); }
template<typename Alloc >
void Botan::StreamCipher::encrypt ( std::vector< byte, Alloc > &  inout) [inline, inherited]

Definition at line 44 of file stream_cipher.h.

         { cipher(&inout[0], &inout[0], inout.size()); }
Returns:
object describing limits on key size

Implements Botan::SymmetricAlgorithm.

Definition at line 29 of file ctr.h.

         {
         return m_cipher->key_spec();
         }
CTR_BE * Botan::CTR_BE::make ( const Spec spec) [static]

Definition at line 15 of file ctr.cpp.

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_count(), c, CTR_BE(), and Botan::Algo_Registry< T >::make().

   {
   if(spec.algo_name() == "CTR-BE" && spec.arg_count() == 1)
      {
      if(BlockCipher* c = Algo_Registry<BlockCipher>::global_registry().make(spec.arg(0)))
         return new CTR_BE(c);
      }
   return nullptr;
   }
size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const [inline, inherited]
Returns:
minimum allowed key length

Definition at line 36 of file sym_algo.h.

References Botan::Key_Length_Specification::maximum_keylength().

         {
         return key_spec().maximum_keylength();
         }
size_t Botan::SymmetricAlgorithm::minimum_keylength ( ) const [inline, inherited]
Returns:
maxmium allowed key length

Definition at line 44 of file sym_algo.h.

         {
         return key_spec().minimum_keylength();
         }
std::string Botan::CTR_BE::name ( ) const [virtual]

Implements Botan::SymmetricAlgorithm.

Definition at line 49 of file ctr.cpp.

Referenced by set_iv().

   {
   return ("CTR-BE(" + m_cipher->name() + ")");
   }
void Botan::CTR_BE::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 68 of file ctr.cpp.

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

   {
   if(!valid_iv_length(iv_len))
      throw Invalid_IV_Length(name(), iv_len);

   const size_t bs = m_cipher->block_size();

   zeroise(m_counter);

   const size_t n_wide = m_counter.size() / m_cipher->block_size();
   buffer_insert(m_counter, 0, iv, iv_len);

   // Set m_counter blocks to IV, IV + 1, ... IV + n
   for(size_t i = 1; i != n_wide; ++i)
      {
      buffer_insert(m_counter, i*bs, &m_counter[(i-1)*bs], bs);

      for(size_t j = 0; j != bs; ++j)
         if(++m_counter[i*bs + (bs - 1 - j)])
            break;
      }

   m_cipher->encrypt_n(&m_counter[0], &m_pad[0], n_wide);
   m_pad_pos = 0;
   }
void Botan::SymmetricAlgorithm::set_key ( const SymmetricKey key) [inline, inherited]

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().

         {
         set_key(key.begin(), key.length());
         }
template<typename Alloc >
void Botan::SymmetricAlgorithm::set_key ( const std::vector< byte, Alloc > &  key) [inline, inherited]

Definition at line 69 of file sym_algo.h.

         {
         set_key(&key[0], key.size());
         }
void Botan::SymmetricAlgorithm::set_key ( const byte  key[],
size_t  length 
) [inline, inherited]

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.

         {
         if(!valid_keylength(length))
            throw Invalid_Key_Length(name(), length);
         key_schedule(key, length);
         }
bool Botan::CTR_BE::valid_iv_length ( size_t  iv_len) const [inline, virtual]
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().

         { return (iv_len <= m_cipher->block_size()); }
bool Botan::SymmetricAlgorithm::valid_keylength ( size_t  length) const [inline, inherited]

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().

         {
         return key_spec().valid_keylength(length);
         }

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