#include <ctr.h>

Inheritance diagram for Botan::CTR_BE:

Public Member Functions
size_t	buffer_size () const override

void	cipher (const uint8_t in[], uint8_t out[], size_t len)

void	cipher (std::span< const uint8_t > in, std::span< uint8_t > out)

void	cipher1 (std::span< uint8_t > buf)

void	cipher1 (uint8_t buf[], size_t len)

void	clear () override

StreamCipher *	clone () const

	CTR_BE (std::unique_ptr< BlockCipher > cipher)

	CTR_BE (std::unique_ptr< BlockCipher > cipher, size_t ctr_size)

void	decrypt (std::span< uint8_t > inout)

size_t	default_iv_length () const override

void	encipher (std::span< uint8_t > inout)

void	encrypt (std::span< uint8_t > inout)

bool	has_keying_material () const override

Key_Length_Specification	key_spec () const override

template<concepts::resizable_byte_buffer T = secure_vector<uint8_t>>
T	keystream_bytes (size_t bytes)

size_t	maximum_keylength () const

size_t	minimum_keylength () const

std::string	name () const override

std::unique_ptr< StreamCipher >	new_object () const override

virtual std::string	provider () const

void	seek (uint64_t offset) override

void	set_iv (const uint8_t iv[], size_t iv_len)

void	set_iv (std::span< const uint8_t > iv)

void	set_key (const SymmetricKey &key)

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

void	set_key (std::span< const uint8_t > key)

bool	valid_iv_length (size_t iv_len) const override

bool	valid_keylength (size_t length) const

void	write_keystream (std::span< uint8_t > out)

void	write_keystream (uint8_t out[], size_t len)

Static Public Member Functions
static std::unique_ptr< StreamCipher >	create (std::string_view algo_spec, std::string_view provider="")

static std::unique_ptr< StreamCipher >	create_or_throw (std::string_view algo_spec, std::string_view provider="")

static std::vector< std::string >	providers (std::string_view algo_spec)

Protected Member Functions
void	assert_key_material_set () const

void	assert_key_material_set (bool predicate) const

Detailed Description

CTR-BE (Counter mode, big-endian)

Definition at line 19 of file ctr.h.

Constructor & Destructor Documentation

◆ CTR_BE() [1/2]

Botan::CTR_BE::CTR_BE ( std::unique_ptr< BlockCipher > cipher )

explicit

Parameters

cipher the block cipher to use

Definition at line 16 of file ctr.cpp.

                                                :
   m_cipher(std::move(cipher)),
   m_block_size(m_cipher->block_size()),
   m_ctr_size(m_block_size),
   m_ctr_blocks(m_cipher->parallel_bytes() / m_block_size),
   m_counter(m_cipher->parallel_bytes()),
   m_pad(m_counter.size()),
   m_pad_pos(0)
   {
   }

◆ CTR_BE() [2/2]

Botan::CTR_BE::CTR_BE	(	std::unique_ptr< BlockCipher >	cipher,
		size_t	ctr_size
	)

Definition at line 27 of file ctr.cpp.

                                                                 :
   m_cipher(std::move(cipher)),
   m_block_size(m_cipher->block_size()),
   m_ctr_size(ctr_size),
   m_ctr_blocks(m_cipher->parallel_bytes() / m_block_size),
   m_counter(m_cipher->parallel_bytes()),
   m_pad(m_counter.size()),
   m_pad_pos(0)
   {
   BOTAN_ARG_CHECK(m_ctr_size >= 4 && m_ctr_size <= m_block_size,
                   "Invalid CTR-BE counter size");
   }

References BOTAN_ARG_CHECK.

Member Function Documentation

◆ assert_key_material_set() [1/2]

void Botan::SymmetricAlgorithm::assert_key_material_set ( ) const

inlineprotectedinherited

Definition at line 182 of file sym_algo.h.

         {
         assert_key_material_set(has_keying_material());
         }

◆ assert_key_material_set() [2/2]

void Botan::SymmetricAlgorithm::assert_key_material_set ( bool predicate ) const

inlineprotectedinherited

Definition at line 187 of file sym_algo.h.

         {
         if(!predicate)
            throw_key_not_set_error();
         }

◆ buffer_size()

size_t Botan::CTR_BE::buffer_size ( ) const

overridevirtual

Return the optimium buffer size to use with this cipher

Most stream ciphers internally produce blocks of bytes. This function returns that block size. Aligning buffer sizes to a multiple of this size may improve performance by reducing internal buffering overhead.

Note the return value of this function may change for any particular algorithm due to changes in the implementation from release to release, or changes in the runtime environment (such as CPUID indicating availability of an optimized implementation). It is not intrinsic to the algorithm; it is just a suggestion for gaining best performance.

Implements Botan::StreamCipher.

Definition at line 59 of file ctr.cpp.

   {
   return m_pad.size();
   }

◆ cipher() [1/2]

void Botan::StreamCipher::cipher	(	const uint8_t	in[],
		uint8_t	out[],
		size_t	len
	)

inlineinherited

Encrypt or decrypt a message

Parameters

in	the plaintext
out	the byte array to hold the output, i.e. the ciphertext
len	the length of both in and out in bytes

Definition at line 61 of file stream_cipher.h.

62 { cipher_bytes(in, out, len); }

Botan::StreamCipher::cipher_bytes

virtual void cipher_bytes(const uint8_t in[], uint8_t out[], size_t len)=0

Referenced by Botan::StreamCipher::create(), Botan::Sodium::crypto_stream_salsa20_xor_ic(), and Botan::Sodium::crypto_stream_xsalsa20_xor_ic().

◆ cipher() [2/2]

void Botan::StreamCipher::cipher	(	std::span< const uint8_t >	in,
		std::span< uint8_t >	out
	)

inlineinherited

Encrypt or decrypt a message

Parameters

in	the plaintext
out	the byte array to hold the output, i.e. the ciphertext with at least the same size as `in`

Definition at line 70 of file stream_cipher.h.

         {
         BOTAN_ARG_CHECK(in.size() <= out.size(),
                         "Output buffer of stream cipher must be at least as long as input buffer");
         cipher_bytes(in.data(), out.data(), in.size());
         }

References BOTAN_ARG_CHECK.

◆ cipher1() [1/2]

void Botan::StreamCipher::cipher1 ( std::span< uint8_t > buf )

inlineinherited

Encrypt or decrypt a message The message is encrypted/decrypted in place.

Parameters

buf	the plaintext / ciphertext

Definition at line 125 of file stream_cipher.h.

126 { cipher(buf, buf); }

◆ cipher1() [2/2]

void Botan::StreamCipher::cipher1	(	uint8_t	buf[],
		size_t	len
	)

inlineinherited

Encrypt or decrypt a message The message is encrypted/decrypted in place.

Parameters

buf	the plaintext / ciphertext
len	the length of buf in bytes

Definition at line 117 of file stream_cipher.h.

118 { cipher(buf, buf, len); }

◆ clear()

void Botan::CTR_BE::clear ( )

overridevirtual

Reset the internal state. This includes not just the key, but any partial message that may have been in process.

Implements Botan::SymmetricAlgorithm.

Definition at line 40 of file ctr.cpp.

   {
   m_cipher->clear();
   zeroise(m_pad);
   zeroise(m_counter);
   zap(m_iv);
   m_pad_pos = 0;
   }

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

◆ clone()

StreamCipher * Botan::StreamCipher::clone ( ) const

inlineinherited

Returns: a new object representing the same algorithm as *this

Definition at line 199 of file stream_cipher.h.

         {
         return this->new_object().release();
         }

◆ create()

std::unique_ptr< StreamCipher > Botan::StreamCipher::create	(	std::string_view	algo_spec,
		std::string_view	provider = `""`
	)

staticinherited

Create an instance based on a name If provider is empty then best available is chosen.

Parameters

algo_spec	algorithm name
provider	provider implementation to use

Returns: a null pointer if the algo/provider combination cannot be found

Definition at line 38 of file stream_cipher.cpp.

   {
#if defined(BOTAN_HAS_SHAKE_CIPHER)
   if(algo_spec == "SHAKE-128" || algo_spec == "SHAKE-128-XOF")
      {
      if(provider.empty() || provider == "base")
         return std::make_unique<SHAKE_128_Cipher>();
      }
 
   if(algo_spec == "SHAKE-256" || algo_spec == "SHAKE-256-XOF")
      {
      if(provider.empty() || provider == "base")
         return std::make_unique<SHAKE_256_Cipher>();
      }
#endif
 
#if defined(BOTAN_HAS_CHACHA)
   if(algo_spec == "ChaCha20")
      {
      if(provider.empty() || provider == "base")
         return std::make_unique<ChaCha>(20);
      }
#endif
 
#if defined(BOTAN_HAS_SALSA20)
   if(algo_spec == "Salsa20")
      {
      if(provider.empty() || provider == "base")
         return std::make_unique<Salsa20>();
      }
#endif
 
   const SCAN_Name req(algo_spec);
 
#if defined(BOTAN_HAS_CTR_BE)
   if((req.algo_name() == "CTR-BE" || req.algo_name() == "CTR") && req.arg_count_between(1,2))
      {
      if(provider.empty() || provider == "base")
         {
         auto cipher = BlockCipher::create(req.arg(0));
         if(cipher)
            {
            size_t ctr_size = req.arg_as_integer(1, cipher->block_size());
            return std::make_unique<CTR_BE>(std::move(cipher), ctr_size);
            }
         }
      }
#endif
 
#if defined(BOTAN_HAS_CHACHA)
   if(req.algo_name() == "ChaCha")
      {
      if(provider.empty() || provider == "base")
         return std::make_unique<ChaCha>(req.arg_as_integer(0, 20));
      }
#endif
 
#if defined(BOTAN_HAS_OFB)
   if(req.algo_name() == "OFB" && req.arg_count() == 1)
      {
      if(provider.empty() || provider == "base")
         {
         if(auto cipher = BlockCipher::create(req.arg(0)))
            return std::make_unique<OFB>(std::move(cipher));
         }
      }
#endif
 
#if defined(BOTAN_HAS_RC4)
 
   if(req.algo_name() == "RC4" ||
      req.algo_name() == "ARC4" ||
      req.algo_name() == "MARK-4")
      {
      const size_t skip = (req.algo_name() == "MARK-4") ? 256 : req.arg_as_integer(0, 0);
 
      if(provider.empty() || provider == "base")
         {
         return std::make_unique<RC4>(skip);
         }
      }
 
#endif
 
   BOTAN_UNUSED(req);
   BOTAN_UNUSED(provider);
 
   return nullptr;
   }

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_as_integer(), Botan::SCAN_Name::arg_count(), Botan::SCAN_Name::arg_count_between(), BOTAN_UNUSED, Botan::StreamCipher::cipher(), Botan::BlockCipher::create(), and Botan::StreamCipher::provider().

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

◆ create_or_throw()

std::unique_ptr< StreamCipher > Botan::StreamCipher::create_or_throw	(	std::string_view	algo_spec,
		std::string_view	provider = `""`
	)

staticinherited

Create an instance based on a name If provider is empty then best available is chosen.

Parameters

algo_spec	algorithm name
provider	provider implementation to use Throws a Lookup_Error if the algo/provider combination cannot be found

Definition at line 131 of file stream_cipher.cpp.

   {
   if(auto sc = StreamCipher::create(algo, provider))
      {
      return sc;
      }
   throw Lookup_Error("Stream cipher", algo, provider);
   }

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

◆ decrypt()

void Botan::StreamCipher::decrypt ( std::span< uint8_t > inout )

inlineinherited

Decrypt a message in place The message is decrypted in place.

Parameters

inout the plaintext / ciphertext

Definition at line 149 of file stream_cipher.h.

150 { cipher(inout.data(), inout.data(), inout.size()); }

◆ default_iv_length()

size_t Botan::CTR_BE::default_iv_length ( ) const

overridevirtual

Return the default (preferred) nonce length If this function returns 0, then this cipher does not support nonces

Default implementation returns 0

Reimplemented from Botan::StreamCipher.

Definition at line 49 of file ctr.cpp.

   {
   return m_block_size;
   }

◆ encipher()

void Botan::StreamCipher::encipher ( std::span< uint8_t > inout )

inlineinherited

Encrypt a message The message is encrypted/decrypted in place.

Parameters

inout the plaintext / ciphertext

Definition at line 133 of file stream_cipher.h.

134 { cipher(inout.data(), inout.data(), inout.size()); }

◆ encrypt()

void Botan::StreamCipher::encrypt ( std::span< uint8_t > inout )

inlineinherited

Encrypt a message The message is encrypted in place.

Parameters

inout the plaintext / ciphertext

Definition at line 141 of file stream_cipher.h.

142 { cipher(inout.data(), inout.data(), inout.size()); }

◆ has_keying_material()

bool Botan::CTR_BE::has_keying_material ( ) const

overridevirtual

Returns: true if a key has been set on this object

Implements Botan::SymmetricAlgorithm.

Definition at line 74 of file ctr.cpp.

   {
   return m_cipher->has_keying_material();
   }

◆ key_spec()

Key_Length_Specification Botan::CTR_BE::key_spec ( ) const

overridevirtual

Returns: object describing limits on key size

Implements Botan::SymmetricAlgorithm.

Definition at line 64 of file ctr.cpp.

   {
   return m_cipher->key_spec();
   }

◆ keystream_bytes()

template<concepts::resizable_byte_buffer T = secure_vector<uint8_t>>

T Botan::StreamCipher::keystream_bytes ( size_t bytes )

inlineinherited

Get bytes from the keystream

Parameters

bytes The number of bytes to be produced

Definition at line 104 of file stream_cipher.h.

         {
         T out(bytes);
         write_keystream(out);
         return out;
         }

References T.

◆ maximum_keylength()

size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const

inlineinherited

Returns: maximum allowed key length

Definition at line 123 of file sym_algo.h.

         {
         return key_spec().maximum_keylength();
         }

◆ minimum_keylength()

size_t Botan::SymmetricAlgorithm::minimum_keylength ( ) const

inlineinherited

Returns: minimum allowed key length

Definition at line 131 of file sym_algo.h.

         {
         return key_spec().minimum_keylength();
         }

◆ name()

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

overridevirtual

Returns: the algorithm name

Implements Botan::SymmetricAlgorithm.

Definition at line 87 of file ctr.cpp.

   {
   if(m_ctr_size == m_block_size)
      return fmt("CTR-BE({})", m_cipher->name());
   else
      return fmt("CTR-BE({},{})", m_cipher->name(), m_ctr_size);
   }

References Botan::fmt().

◆ new_object()

std::unique_ptr< StreamCipher > Botan::CTR_BE::new_object ( ) const

overridevirtual

Returns: new object representing the same algorithm as *this

Implements Botan::StreamCipher.

Definition at line 69 of file ctr.cpp.

   {
   return std::make_unique<CTR_BE>(m_cipher->new_object(), m_ctr_size);
   }

◆ provider()

virtual std::string Botan::StreamCipher::provider ( ) const

inlinevirtualinherited

Returns: provider information about this implementation. Default is "base", might also return "sse2", "avx2" or some other arbitrary string.

Reimplemented in Botan::ChaCha.

Definition at line 219 of file stream_cipher.h.

219{ return "base"; }

Referenced by Botan::StreamCipher::create(), and Botan::StreamCipher::create_or_throw().

◆ providers()

std::vector< std::string > Botan::StreamCipher::providers ( std::string_view algo_spec )

staticinherited

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

Definition at line 141 of file stream_cipher.cpp.

   {
   return probe_providers_of<StreamCipher>(algo_spec);
   }

◆ seek()

void Botan::CTR_BE::seek ( uint64_t offset )

overridevirtual

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

Parameters

offset the offset where we begin to generate the keystream

Implements Botan::StreamCipher.

Definition at line 239 of file ctr.cpp.

   {
   assert_key_material_set();
 
   const uint64_t base_counter = m_ctr_blocks * (offset / m_counter.size());
 
   zeroise(m_counter);
   buffer_insert(m_counter, 0, m_iv);
 
   const size_t BS = m_block_size;
 
   // Set m_counter blocks to IV, IV + 1, ... IV + n
 
   if(m_ctr_size == 4 && BS >= 8)
      {
      const uint32_t low32 = load_be<uint32_t>(&m_counter[BS-4], 0);
 
      if(m_ctr_blocks >= 4 && is_power_of_2(m_ctr_blocks))
         {
         size_t written = 1;
         while(written < m_ctr_blocks)
            {
            copy_mem(&m_counter[written*BS], &m_counter[0], BS*written);
            written *= 2;
            }
         }
      else
         {
         for(size_t i = 1; i != m_ctr_blocks; ++i)
            {
            copy_mem(&m_counter[i*BS], &m_counter[0], BS - 4);
            }
         }
 
      for(size_t i = 1; i != m_ctr_blocks; ++i)
         {
         const uint32_t c = static_cast<uint32_t>(low32 + i);
         store_be(c, &m_counter[(BS-4)+i*BS]);
         }
      }
   else
      {
      // do everything sequentially:
      for(size_t i = 1; i != m_ctr_blocks; ++i)
         {
         buffer_insert(m_counter, i*BS, &m_counter[(i-1)*BS], BS);
 
         for(size_t j = 0; j != m_ctr_size; ++j)
            if(++m_counter[i*BS + (BS - 1 - j)])
               break;
         }
      }
 
   if(base_counter > 0)
      add_counter(base_counter);
 
   m_cipher->encrypt_n(m_counter.data(), m_pad.data(), m_ctr_blocks);
   m_pad_pos = offset % m_counter.size();
   }

References Botan::SymmetricAlgorithm::assert_key_material_set(), Botan::buffer_insert(), Botan::copy_mem(), Botan::is_power_of_2(), Botan::load_be< uint32_t >(), Botan::store_be(), and Botan::zeroise().

◆ set_iv() [1/2]

void Botan::StreamCipher::set_iv	(	const uint8_t	iv[],
		size_t	iv_len
	)

inlineinherited

Resync the cipher using the IV

Parameters

iv	the initialization vector
iv_len	the length of the IV in bytes

Definition at line 172 of file stream_cipher.h.

173 { set_iv_bytes(iv, iv_len); }

Botan::StreamCipher::set_iv_bytes

virtual void set_iv_bytes(const uint8_t iv[], size_t iv_len)=0

Referenced by Botan::Sodium::crypto_stream_salsa20(), Botan::Sodium::crypto_stream_salsa20_xor_ic(), Botan::Sodium::crypto_stream_xsalsa20(), Botan::Sodium::crypto_stream_xsalsa20_xor_ic(), Botan::Sodium::randombytes_buf_deterministic(), and Botan::SIV_Mode::set_ctr_iv().

◆ set_iv() [2/2]

void Botan::StreamCipher::set_iv ( std::span< const uint8_t > iv )

inlineinherited

Resync the cipher using the IV

Parameters

iv	the initialization vector

Definition at line 179 of file stream_cipher.h.

180 { set_iv_bytes(iv.data(), iv.size()); }

◆ set_key() [1/3]

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

inlineinherited

Set the symmetric key of this object.

Parameters

key	the SymmetricKey to be set.

Definition at line 150 of file sym_algo.h.

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

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

Referenced by Botan::Sodium::crypto_stream_salsa20(), Botan::Sodium::crypto_stream_salsa20_xor_ic(), Botan::Sodium::crypto_stream_xsalsa20(), Botan::Sodium::crypto_stream_xsalsa20_xor_ic(), Botan::FPE::fe1_decrypt(), Botan::FPE::fe1_encrypt(), and Botan::Sodium::randombytes_buf_deterministic().

◆ set_key() [2/3]

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

inherited

Set the symmetric key of this object.

Parameters

key	the to be set as a byte array.
length	in bytes of key param

Definition at line 17 of file sym_algo.cpp.

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

References Botan::SymmetricAlgorithm::name(), and Botan::SymmetricAlgorithm::valid_keylength().

◆ set_key() [3/3]

void Botan::SymmetricAlgorithm::set_key ( std::span< const uint8_t > key )

inlineinherited

Set the symmetric key of this object.

Parameters

key	the contiguous byte range to be set.

Definition at line 159 of file sym_algo.h.

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

◆ valid_iv_length()

bool Botan::CTR_BE::valid_iv_length ( size_t iv_len ) const

overridevirtual

Parameters

iv_len the length of the IV in bytes

Returns: if the length is valid for this algorithm

Reimplemented from Botan::StreamCipher.

Definition at line 54 of file ctr.cpp.

   {
   return (iv_len <= m_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

length the key length to be checked.

Returns: true if the key length is valid.

Definition at line 141 of file sym_algo.h.

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

Referenced by Botan::SymmetricAlgorithm::set_key().

◆ write_keystream() [1/2]

void Botan::StreamCipher::write_keystream ( std::span< uint8_t > out )

inlineinherited

Fill a given buffer with keystream bytes

The contents of out are ignored/overwritten

Parameters

out	the byte array to hold the keystream

Definition at line 95 of file stream_cipher.h.

96 { generate_keystream(out.data(), out.size()); }

Botan::StreamCipher::generate_keystream

virtual void generate_keystream(uint8_t out[], size_t len)

Definition: stream_cipher.h:230

◆ write_keystream() [2/2]

void Botan::StreamCipher::write_keystream	(	uint8_t	out[],
		size_t	len
	)

inlineinherited

Write keystream bytes to a buffer

The contents of out are ignored/overwritten

Parameters

out	the byte array to hold the keystream
len	the length of out in bytes

Definition at line 85 of file stream_cipher.h.

86 { generate_keystream(out, len); }

Referenced by Botan::Sodium::crypto_stream_salsa20(), Botan::Sodium::crypto_stream_xsalsa20(), and Botan::Sodium::randombytes_buf_deterministic().

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

src/lib/stream/ctr/ctr.h
src/lib/stream/ctr/ctr.cpp

Public Member Functions

Static Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ CTR_BE() [1/2]

◆ CTR_BE() [2/2]

Member Function Documentation

◆ assert_key_material_set() [1/2]

◆ assert_key_material_set() [2/2]

◆ buffer_size()

◆ cipher() [1/2]

◆ cipher() [2/2]

◆ cipher1() [1/2]

◆ cipher1() [2/2]

◆ clear()

◆ clone()

◆ create()

◆ create_or_throw()

◆ decrypt()

◆ default_iv_length()

◆ encipher()

◆ encrypt()

◆ has_keying_material()

◆ key_spec()

◆ keystream_bytes()

◆ maximum_keylength()

◆ minimum_keylength()

◆ name()

◆ new_object()

◆ provider()

◆ providers()

◆ seek()

◆ set_iv() [1/2]

◆ set_iv() [2/2]

◆ set_key() [1/3]

◆ set_key() [2/3]

◆ set_key() [3/3]

◆ valid_iv_length()

◆ valid_keylength()

◆ write_keystream() [1/2]

◆ write_keystream() [2/2]