Botan::CBC_Encryption Class Reference

#include <cbc.h>

Inheritance diagram for Botan::CBC_Encryption:

Public Member Functions
virtual bool	authenticated () const
	CBC_Encryption (BlockCipher *cipher, BlockCipherModePaddingMethod *padding)
void	clear () override
size_t	default_nonce_length () const override
void	finish (secure_vector< uint8_t > &final_block, size_t offset=0) override
Key_Length_Specification	key_spec () const override
size_t	minimum_final_size () const override
std::string	name () const override
size_t	output_length (size_t input_length) const override
size_t	process (uint8_t buf[], size_t size) override
virtual std::string	provider () const
void	reset () override
template<typename Alloc >
void	set_key (const std::vector< uint8_t, Alloc > &key)
void	set_key (const SymmetricKey &key)
void	set_key (const uint8_t key[], size_t length)
template<typename Alloc >
void	start (const std::vector< uint8_t, Alloc > &nonce)
void	start (const uint8_t nonce[], size_t nonce_len)
void	start ()
virtual size_t	tag_size () const
void	update (secure_vector< uint8_t > &buffer, size_t offset=0)
size_t	update_granularity () const override
bool	valid_keylength (size_t length) const
bool	valid_nonce_length (size_t n) const override

Static Public Member Functions
static std::unique_ptr< Cipher_Mode >	create (const std::string &algo, Cipher_Dir direction, const std::string &provider="")
static std::unique_ptr< Cipher_Mode >	create_or_throw (const std::string &algo, Cipher_Dir direction, const std::string &provider="")
static std::vector< std::string >	providers (const std::string &algo_spec)

Protected Member Functions
size_t	block_size () const
const BlockCipher &	cipher () const
const BlockCipherModePaddingMethod &	padding () const
secure_vector< uint8_t > &	state ()
uint8_t *	state_ptr ()

Detailed Description

CBC Encryption

Definition at line 68 of file cbc.h.

Constructor & Destructor Documentation

CBC_Encryption()

Botan::CBC_Encryption::CBC_Encryption ( BlockCipher *  cipher, BlockCipherModePaddingMethod *  padding  )

inline

Parameters

cipher	block cipher to use
padding	padding method to use

Definition at line 75 of file cbc.h.

                                                                                 :
         CBC_Mode(cipher, padding) {}

Member Function Documentation

authenticated()

virtual bool Botan::Cipher_Mode::authenticated ( ) const

inlinevirtualinherited

Returns

true iff this mode provides authentication as well as confidentiality.

Reimplemented in Botan::AEAD_Mode.

Definition at line 179 of file cipher_mode.h.

{ return false; }

block_size()

size_t Botan::CBC_Mode::block_size ( ) const

inlineprotectedinherited

Definition at line 51 of file cbc.h.

Referenced by Botan::CBC_Mode::default_nonce_length(), finish(), Botan::CTS_Encryption::finish(), Botan::CBC_Decryption::finish(), Botan::CTS_Decryption::finish(), Botan::CTS_Encryption::minimum_final_size(), Botan::CBC_Decryption::minimum_final_size(), Botan::CTS_Decryption::minimum_final_size(), output_length(), process(), Botan::CBC_Decryption::process(), Botan::CBC_Mode::valid_nonce_length(), Botan::CTS_Encryption::valid_nonce_length(), and Botan::CTS_Decryption::valid_nonce_length().

{ return m_state.size(); }

cipher()

const BlockCipher& Botan::CBC_Mode::cipher ( ) const

inlineprotectedinherited

Definition at line 41 of file cbc.h.

Referenced by Botan::CTS_Encryption::finish(), Botan::CTS_Decryption::finish(), Botan::CBC_Mode::key_spec(), Botan::CBC_Mode::name(), process(), Botan::CBC_Decryption::process(), and Botan::CBC_Mode::update_granularity().

{ return *m_cipher; }

clear()

void Botan::CBC_Mode::clear ( )

overridevirtualinherited

Zeroise all state See also reset_msg()

Implements Botan::Cipher_Mode.

Definition at line 26 of file cbc.cpp.

References Botan::CBC_Mode::reset().

   {
   m_cipher->clear();
   reset();
   }

create()

std::unique_ptr< Cipher_Mode > Botan::Cipher_Mode::create ( const std::string &  algo, Cipher_Dir  direction, const std::string &  provider = ""  )

staticinherited

Create an AEAD mode

Parameters

algo	the algorithm to create
direction	specify if this should be an encryption or decryption AEAD
provider	optional specification for provider to use

Returns

an AEAD mode or a null pointer if not available

Definition at line 50 of file cipher_mode.cpp.

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_as_integer(), Botan::SCAN_Name::arg_count(), Botan::BlockCipher::create(), Botan::AEAD_Mode::create(), Botan::StreamCipher::create(), Botan::ENCRYPTION, Botan::get_bc_pad(), Botan::make_openssl_cipher_mode(), Botan::parse_algorithm_name(), Botan::Cipher_Mode::provider(), and Botan::split_on().

Referenced by botan_cipher_init(), Botan::Cipher_Mode::create_or_throw(), Botan::get_cipher_mode(), Botan::pbes2_decrypt(), and Botan::Cipher_Mode::providers().

   {
#if defined(BOTAN_HAS_OPENSSL)
   if(provider.empty() || provider == "openssl")
      {
      std::unique_ptr<Cipher_Mode> openssl_cipher(make_openssl_cipher_mode(algo, direction));

      if(openssl_cipher)
         return openssl_cipher;

      if(!provider.empty())
         return std::unique_ptr<Cipher_Mode>();
      }
#endif

#if defined(BOTAN_HAS_STREAM_CIPHER)
   if(auto sc = StreamCipher::create(algo))
      {
      return std::unique_ptr<Cipher_Mode>(new Stream_Cipher_Mode(sc.release()));
      }
#endif

#if defined(BOTAN_HAS_AEAD_MODES)
   if(auto aead = AEAD_Mode::create(algo, direction))
      {
      return std::unique_ptr<Cipher_Mode>(aead.release());
      }
#endif

   if(algo.find('/') != std::string::npos)
      {
      const std::vector<std::string> algo_parts = split_on(algo, '/');
      const std::string cipher_name = algo_parts[0];
      const std::vector<std::string> mode_info = parse_algorithm_name(algo_parts[1]);

      if(mode_info.empty())
         return std::unique_ptr<Cipher_Mode>();

      std::ostringstream alg_args;

      alg_args << '(' << cipher_name;
      for(size_t i = 1; i < mode_info.size(); ++i)
         alg_args << ',' << mode_info[i];
      for(size_t i = 2; i < algo_parts.size(); ++i)
         alg_args << ',' << algo_parts[i];
      alg_args << ')';

      const std::string mode_name = mode_info[0] + alg_args.str();
      return Cipher_Mode::create(mode_name, direction, provider);
      }

#if defined(BOTAN_HAS_BLOCK_CIPHER)

   SCAN_Name spec(algo);

   if(spec.arg_count() == 0)
      {
      return std::unique_ptr<Cipher_Mode>();
      }

   std::unique_ptr<BlockCipher> bc(BlockCipher::create(spec.arg(0), provider));

   if(!bc)
      {
      return std::unique_ptr<Cipher_Mode>();
      }

#if defined(BOTAN_HAS_MODE_CBC)
   if(spec.algo_name() == "CBC")
      {
      const std::string padding = spec.arg(1, "PKCS7");

      if(padding == "CTS")
         {
         if(direction == ENCRYPTION)
            return std::unique_ptr<Cipher_Mode>(new CTS_Encryption(bc.release()));
         else
            return std::unique_ptr<Cipher_Mode>(new CTS_Decryption(bc.release()));
         }
      else
         {
         std::unique_ptr<BlockCipherModePaddingMethod> pad(get_bc_pad(padding));

         if(pad)
            {
            if(direction == ENCRYPTION)
               return std::unique_ptr<Cipher_Mode>(new CBC_Encryption(bc.release(), pad.release()));
            else
               return std::unique_ptr<Cipher_Mode>(new CBC_Decryption(bc.release(), pad.release()));
            }
         }
      }
#endif

#if defined(BOTAN_HAS_MODE_XTS)
   if(spec.algo_name() == "XTS")
      {
      if(direction == ENCRYPTION)
         return std::unique_ptr<Cipher_Mode>(new XTS_Encryption(bc.release()));
      else
         return std::unique_ptr<Cipher_Mode>(new XTS_Decryption(bc.release()));
      }
#endif

#if defined(BOTAN_HAS_MODE_CFB)
   if(spec.algo_name() == "CFB")
      {
      const size_t feedback_bits = spec.arg_as_integer(1, 8*bc->block_size());
      if(direction == ENCRYPTION)
         return std::unique_ptr<Cipher_Mode>(new CFB_Encryption(bc.release(), feedback_bits));
      else
         return std::unique_ptr<Cipher_Mode>(new CFB_Decryption(bc.release(), feedback_bits));
      }
#endif

#endif

   return std::unique_ptr<Cipher_Mode>();
   }

create_or_throw()

std::unique_ptr< Cipher_Mode > Botan::Cipher_Mode::create_or_throw ( const std::string &  algo, Cipher_Dir  direction, const std::string &  provider = ""  )

staticinherited

Create an AEAD mode, or throw

Parameters

algo	the algorithm to create
direction	specify if this should be an encryption or decryption AEAD
provider	optional specification for provider to use

Returns

an AEAD mode, or throw an exception

Definition at line 40 of file cipher_mode.cpp.

References Botan::Cipher_Mode::create(), and Botan::Cipher_Mode::provider().

Referenced by Botan::ECIES_System_Params::create_cipher(), Botan::CryptoBox::decrypt_bin(), Botan::CryptoBox::encrypt(), and Botan::get_cipher().

   {
   if(auto mode = Cipher_Mode::create(algo, direction, provider))
      return mode;

   throw Lookup_Error("Cipher mode", algo, provider);
   }

default_nonce_length()

size_t Botan::CBC_Mode::default_nonce_length ( ) const

overridevirtualinherited

Returns

the default size for a nonce

Implements Botan::Cipher_Mode.

Definition at line 55 of file cbc.cpp.

References Botan::CBC_Mode::block_size().

   {
   return block_size();
   }

finish()

void Botan::CBC_Encryption::finish ( secure_vector< uint8_t > &  final_block, size_t  offset = 0  )

overridevirtual

Complete processing of a message.

Parameters

final_block	in/out parameter which must be at least minimum_final_size() bytes, and will be set to any final output
offset	an offset into final_block to begin processing

Implements Botan::Cipher_Mode.

Reimplemented in Botan::CTS_Encryption.

Definition at line 121 of file cbc.cpp.

References Botan::BlockCipherModePaddingMethod::add_padding(), Botan::CBC_Mode::block_size(), BOTAN_ASSERT, Botan::CBC_Mode::name(), Botan::CBC_Mode::padding(), and Botan::Cipher_Mode::update().

   {
   BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");

   const size_t BS = block_size();

   const size_t bytes_in_final_block = (buffer.size()-offset) % BS;

   padding().add_padding(buffer, bytes_in_final_block, BS);

   if((buffer.size()-offset) % BS)
      throw Exception("Did not pad to full block size in " + name());

   update(buffer, offset);
   }

key_spec()

Key_Length_Specification Botan::CBC_Mode::key_spec ( ) const

overridevirtualinherited

Returns

object describing limits on key size

Implements Botan::Cipher_Mode.

Definition at line 50 of file cbc.cpp.

References Botan::CBC_Mode::cipher(), and Botan::SymmetricAlgorithm::key_spec().

   {
   return cipher().key_spec();
   }

minimum_final_size()

size_t Botan::CBC_Encryption::minimum_final_size ( ) const

overridevirtual

Returns

required minimium size to finalize() - may be any length larger than this.

Implements Botan::Cipher_Mode.

Reimplemented in Botan::CTS_Encryption.

Definition at line 84 of file cbc.cpp.

   {
   return 0;
   }

name()

std::string Botan::CBC_Mode::name ( ) const

overridevirtualinherited

Implements Botan::Cipher_Mode.

Definition at line 37 of file cbc.cpp.

References Botan::CBC_Mode::cipher(), Botan::BlockCipherModePaddingMethod::name(), Botan::SymmetricAlgorithm::name(), and Botan::CBC_Mode::padding().

Referenced by finish(), Botan::CTS_Encryption::finish(), Botan::CBC_Decryption::finish(), and Botan::CTS_Decryption::finish().

   {
   if(m_padding)
      return cipher().name() + "/CBC/" + padding().name();
   else
      return cipher().name() + "/CBC/CTS";
   }

output_length()

size_t Botan::CBC_Encryption::output_length ( size_t  input_length ) const

overridevirtual

Returns the size of the output if this transform is used to process a message with input_length bytes. Will throw if unable to give a precise answer.

Implements Botan::Cipher_Mode.

Reimplemented in Botan::CTS_Encryption.

Definition at line 89 of file cbc.cpp.

References Botan::CBC_Mode::block_size(), and Botan::round_up().

   {
   if(input_length == 0)
      return block_size();
   else
      return round_up(input_length, block_size());
   }

padding()

const BlockCipherModePaddingMethod& Botan::CBC_Mode::padding ( ) const

inlineprotectedinherited

Definition at line 43 of file cbc.h.

References BOTAN_ASSERT_NONNULL.

Referenced by finish(), Botan::CBC_Decryption::finish(), and Botan::CBC_Mode::name().

         {
         BOTAN_ASSERT_NONNULL(m_padding);
         return *m_padding;
         }

process()

size_t Botan::CBC_Encryption::process ( uint8_t  msg[], size_t  msg_len  )

overridevirtual

Process message blocks

Input must be a multiple of update_granularity

Processes msg in place and returns bytes written. Normally this will be either msg_len (indicating the entire message was processed) or for certain AEAD modes zero (indicating that the mode requires the entire message be processed in one pass).

Parameters

msg	the message to be processed
msg_len	length of the message in bytes

Implements Botan::Cipher_Mode.

Definition at line 97 of file cbc.cpp.

References Botan::CBC_Mode::block_size(), BOTAN_ASSERT, Botan::CBC_Mode::cipher(), Botan::BlockCipher::encrypt(), Botan::CBC_Mode::state(), Botan::CBC_Mode::state_ptr(), and Botan::xor_buf().

   {
   const size_t BS = block_size();

   BOTAN_ASSERT(sz % BS == 0, "CBC input is full blocks");
   const size_t blocks = sz / BS;

   if(blocks > 0)
      {
      xor_buf(&buf[0], state_ptr(), BS);
      cipher().encrypt(&buf[0]);

      for(size_t i = 1; i != blocks; ++i)
         {
         xor_buf(&buf[BS*i], &buf[BS*(i-1)], BS);
         cipher().encrypt(&buf[BS*i]);
         }

      state().assign(&buf[BS*(blocks-1)], &buf[BS*blocks]);
      }

   return sz;
   }

provider()

virtual std::string Botan::Cipher_Mode::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::GCM_Mode.

Definition at line 236 of file cipher_mode.h.

Referenced by Botan::AEAD_Mode::create(), Botan::Cipher_Mode::create(), Botan::AEAD_Mode::create_or_throw(), and Botan::Cipher_Mode::create_or_throw().

{ return "base"; }

providers()

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

staticinherited

Returns

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

Parameters

algo_spec

algorithm name

Definition at line 173 of file cipher_mode.cpp.

References Botan::Cipher_Mode::create(), and Botan::ENCRYPTION.

   {
   const std::vector<std::string>& possible = { "base", "openssl" };
   std::vector<std::string> providers;
   for(auto&& prov : possible)
      {
      std::unique_ptr<Cipher_Mode> mode = Cipher_Mode::create(algo_spec, ENCRYPTION, prov);
      if(mode)
         {
         providers.push_back(prov); // available
         }
      }
   return providers;
   }

reset()

void Botan::CBC_Mode::reset ( )

overridevirtualinherited

Resets just the message specific state and allows encrypting again under the existing key

Implements Botan::Cipher_Mode.

Reimplemented in Botan::CBC_Decryption.

Definition at line 32 of file cbc.cpp.

References Botan::zeroise().

Referenced by Botan::CBC_Mode::clear().

   {
   zeroise(m_state);
   }

set_key() [1/3]

template<typename Alloc >

void Botan::Cipher_Mode::set_key ( const std::vector< uint8_t, Alloc > &  key )

inlineinherited

Set the symmetric key of this transform

Parameters

key	contains the key material

Definition at line 206 of file cipher_mode.h.

Referenced by botan_cipher_set_key().

         {
         set_key(key.data(), key.size());
         }

set_key() [2/3]

void Botan::Cipher_Mode::set_key ( const SymmetricKey &  key )

inlineinherited

Set the symmetric key of this transform

Parameters

key	contains the key material

Definition at line 215 of file cipher_mode.h.

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

         {
         set_key(key.begin(), key.length());
         }

set_key() [3/3]

void Botan::Cipher_Mode::set_key ( const uint8_t  key[], size_t  length  )

inlineinherited

Set the symmetric key of this transform

Parameters

key	contains the key material
length	in bytes of key param

Definition at line 225 of file cipher_mode.h.

         {
         if(!valid_keylength(length))
            throw Invalid_Key_Length(name(), length);
         key_schedule(key, length);
         }

start() [1/3]

template<typename Alloc >

void Botan::Cipher_Mode::start ( const std::vector< uint8_t, Alloc > &  nonce )

inlineinherited

Begin processing a message.

Parameters

nonce

the per message nonce

Definition at line 72 of file cipher_mode.h.

Referenced by botan_cipher_start(), and Botan::TLS::write_record().

         {
         start_msg(nonce.data(), nonce.size());
         }

start() [2/3]

void Botan::Cipher_Mode::start ( const uint8_t  nonce[], size_t  nonce_len  )

inlineinherited

Begin processing a message.

Parameters

nonce	the per message nonce
nonce_len	length of nonce

Definition at line 82 of file cipher_mode.h.

         {
         start_msg(nonce, nonce_len);
         }

start() [3/3]

void Botan::Cipher_Mode::start ( )

inlineinherited

Begin processing a message.

Definition at line 90 of file cipher_mode.h.

         {
         return start_msg(nullptr, 0);
         }

state()

secure_vector<uint8_t>& Botan::CBC_Mode::state ( )

inlineprotectedinherited

Definition at line 49 of file cbc.h.

Referenced by process(), and Botan::CBC_Decryption::reset().

{ return m_state; }

state_ptr()

uint8_t* Botan::CBC_Mode::state_ptr ( )

inlineprotectedinherited

Definition at line 53 of file cbc.h.

Referenced by Botan::CTS_Encryption::finish(), Botan::CTS_Decryption::finish(), process(), and Botan::CBC_Decryption::process().

{ return m_state.data(); }

tag_size()

virtual size_t Botan::Cipher_Mode::tag_size ( ) const

inlinevirtualinherited

Returns

the size of the authentication tag used (in bytes)

Reimplemented in Botan::SIV_Mode, Botan::OCB_Mode, Botan::CCM_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::ChaCha20Poly1305_Mode, Botan::GCM_Mode, and Botan::EAX_Mode.

Definition at line 184 of file cipher_mode.h.

Referenced by botan_cipher_get_tag_length().

{ return 0; }

update()

void Botan::Cipher_Mode::update ( secure_vector< uint8_t > &  buffer, size_t  offset = 0  )

inlineinherited

Process some data. Input must be in size update_granularity() uint8_t blocks.

Parameters

buffer	in/out parameter which will possibly be resized
offset	an offset into blocks to begin processing

Definition at line 115 of file cipher_mode.h.

References BOTAN_ASSERT.

Referenced by botan_cipher_update(), Botan::XTS_Encryption::finish(), Botan::ChaCha20Poly1305_Encryption::finish(), Botan::CFB_Encryption::finish(), finish(), Botan::EAX_Encryption::finish(), Botan::XTS_Decryption::finish(), Botan::CFB_Decryption::finish(), Botan::CTS_Encryption::finish(), Botan::CBC_Decryption::finish(), Botan::TLS::TLS_CBC_HMAC_AEAD_Encryption::finish(), Botan::CTS_Decryption::finish(), and Botan::TLS::TLS_CBC_HMAC_AEAD_Decryption::finish().

         {
         BOTAN_ASSERT(buffer.size() >= offset, "Offset ok");
         uint8_t* buf = buffer.data() + offset;
         const size_t buf_size = buffer.size() - offset;

         const size_t written = process(buf, buf_size);
         buffer.resize(offset + written);
         }

update_granularity()

size_t Botan::CBC_Mode::update_granularity ( ) const

overridevirtualinherited

Returns

size of required blocks to update

Implements Botan::Cipher_Mode.

Definition at line 45 of file cbc.cpp.

References Botan::CBC_Mode::cipher(), and Botan::BlockCipher::parallel_bytes().

   {
   return cipher().parallel_bytes();
   }

valid_keylength()

bool Botan::Cipher_Mode::valid_keylength ( size_t  length ) const

inlineinherited

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

Parameters

length

the key length to be checked.

Returns

true if the key length is valid.

Definition at line 196 of file cipher_mode.h.

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

valid_nonce_length()

bool Botan::CBC_Mode::valid_nonce_length ( size_t  nonce_len ) const

overridevirtualinherited

Returns

true iff nonce_len is a valid length for the nonce

Implements Botan::Cipher_Mode.

Reimplemented in Botan::CTS_Decryption, and Botan::CTS_Encryption.

Definition at line 60 of file cbc.cpp.

References Botan::CBC_Mode::block_size().

   {
   return (n == 0 || n == block_size());
   }

---

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

• src/lib/modes/cbc/cbc.h
• src/lib/modes/cbc/cbc.cpp