Botan::Cipher_Mode Class Reference

#include <cipher_mode.h>

Inheritance diagram for Botan::Cipher_Mode:

Public Member Functions
bool	authenticated () const
virtual void	clear ()=0
virtual size_t	default_nonce_length () const =0
void	finish (secure_vector< uint8_t > &final_block, size_t offset=0)
template<concepts::resizable_byte_buffer T>
void	finish (T &final_block, size_t offset=0)
virtual bool	has_keying_material () const =0
virtual size_t	ideal_granularity () const =0
virtual Key_Length_Specification	key_spec () const =0
size_t	maximum_keylength () const
virtual size_t	minimum_final_size () const =0
size_t	minimum_keylength () const
virtual std::string	name () const =0
virtual size_t	output_length (size_t input_length) const =0
size_t	process (std::span< uint8_t > msg)
size_t	process (uint8_t msg[], size_t msg_len)
virtual std::string	provider () const
virtual bool	requires_entire_message () const
virtual void	reset ()=0
void	set_key (const OctetString &key)
void	set_key (const uint8_t key[], size_t length)
void	set_key (std::span< const uint8_t > key)
void	start ()
void	start (const uint8_t nonce[], size_t nonce_len)
void	start (std::span< const uint8_t > nonce)
virtual size_t	tag_size () const
template<concepts::resizable_byte_buffer T>
void	update (T &buffer, size_t offset=0)
virtual size_t	update_granularity () const =0
bool	valid_keylength (size_t length) const
virtual bool	valid_nonce_length (size_t nonce_len) const =0

Static Public Member Functions
static std::unique_ptr< Cipher_Mode >	create (std::string_view algo, Cipher_Dir direction, std::string_view provider="")
static std::unique_ptr< Cipher_Mode >	create_or_throw (std::string_view algo, Cipher_Dir direction, 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
virtual void	finish_msg (secure_vector< uint8_t > &final_block, size_t offset=0)=0
virtual size_t	process_msg (uint8_t msg[], size_t msg_len)=0
virtual void	start_msg (const uint8_t nonce[], size_t nonce_len)=0

Detailed Description

Interface for cipher modes

Definition at line 36 of file cipher_mode.h.

Member Function Documentation

assert_key_material_set() [1/2]

void Botan::SymmetricAlgorithm::assert_key_material_set ( ) const

inlineprotectedinherited

Definition at line 145 of file sym_algo.h.

{ assert_key_material_set(has_keying_material()); }

References assert_key_material_set(), and has_keying_material().

Referenced by assert_key_material_set(), Botan::Salsa20::cipher_bytes(), Botan::Lion::decrypt_n(), Botan::Lion::encrypt_n(), Botan::GHASH::final(), Botan::GHASH::nonce_hash(), Botan::GHASH::reset_associated_data(), Botan::ChaCha::seek(), Botan::CTR_BE::seek(), Botan::Salsa20::seek(), Botan::GHASH::set_associated_data(), Botan::OCB_Mode::set_associated_data_n(), Botan::Salsa20::set_iv_bytes(), Botan::GHASH::update(), and Botan::GHASH::update_associated_data().

assert_key_material_set() [2/2]

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

inlineprotectedinherited

Definition at line 147 of file sym_algo.h.

                                                         {
         if(!predicate) {
            throw_key_not_set_error();
         }
      }

authenticated()

bool Botan::Cipher_Mode::authenticated ( ) const

inline

Return the length in bytes of the authentication tag this algorithm generates. If the mode is not authenticated, this will return 0.

Returns

true iff this mode provides authentication as well as confidentiality.

Definition at line 262 of file cipher_mode.h.

{ return this->tag_size() > 0; }

References tag_size().

clear()

virtual void Botan::SymmetricAlgorithm::clear ( )

pure virtualinherited

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

Implemented in Botan::AES_128, Botan::AES_192, Botan::AES_256, Botan::ANSI_X919_MAC, Botan::ARIA_128, Botan::ARIA_192, Botan::ARIA_256, Botan::Ascon_AEAD128_Mode, Botan::BLAKE2b, Botan::BLAKE2bMAC, Botan::Blowfish, Botan::Camellia_128, Botan::Camellia_192, Botan::Camellia_256, Botan::Cascade_Cipher, Botan::CAST_128, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::ChaCha, Botan::CMAC, Botan::CTR_BE, Botan::DES, Botan::EAX_Mode, Botan::FPE_FE1, Botan::GCM_Mode, Botan::GHASH, Botan::GMAC, Botan::GOST_28147_89, Botan::HMAC, Botan::IDEA, Botan::KMAC, Botan::Kuznyechik, Botan::Lion, Botan::Noekeon, Botan::OCB_Mode, Botan::OFB, Botan::Poly1305, Botan::RC4, Botan::Salsa20, Botan::SEED, Botan::Serpent, Botan::SHACAL2, Botan::SHAKE_Cipher, Botan::SipHash, Botan::SIV_Mode, Botan::SM4, Botan::Threefish_512, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, Botan::TripleDES, Botan::Twofish, and Botan::XTS_Mode.

Referenced by Botan::TLS::TLS_CBC_HMAC_AEAD_Mode::clear(), and Botan::TLS::TLS_NULL_HMAC_AEAD_Mode::clear().

create()

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

static

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 54 of file cipher_mode.cpp.

                                                                          {
#if defined(BOTAN_HAS_COMMONCRYPTO)
   if(provider.empty() || provider == "commoncrypto") {
      if(auto cm = make_commoncrypto_cipher_mode(algo, direction))
         return cm;
 
      if(!provider.empty())
         return nullptr;
   }
#endif
 
   if(provider != "base" && !provider.empty()) {
      return nullptr;
   }
 
#if defined(BOTAN_HAS_STREAM_CIPHER)
   if(auto sc = StreamCipher::create(algo)) {
      return std::make_unique<Stream_Cipher_Mode>(std::move(sc));
   }
#endif
 
#if defined(BOTAN_HAS_AEAD_MODES)
   if(auto aead = AEAD_Mode::create(algo, direction)) {
      return aead;
   }
#endif
 
   if(algo.find('/') != std::string::npos) {
      const std::vector<std::string> algo_parts = split_on(algo, '/');
      const std::string_view 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 mode_name;
 
      mode_name << mode_info[0] << '(' << cipher_name;
      for(size_t i = 1; i < mode_info.size(); ++i) {
         mode_name << ',' << mode_info[i];
      }
      for(size_t i = 2; i < algo_parts.size(); ++i) {
         mode_name << ',' << algo_parts[i];
      }
      mode_name << ')';
 
      return Cipher_Mode::create(mode_name.str(), direction, provider);
   }
 
#if defined(BOTAN_HAS_BLOCK_CIPHER)
 
   const SCAN_Name spec(algo);
 
   if(spec.arg_count() == 0) {
      return std::unique_ptr<Cipher_Mode>();
   }
 
   auto 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 == Cipher_Dir::Encryption) {
            return std::make_unique<CTS_Encryption>(std::move(bc));
         } else {
            return std::make_unique<CTS_Decryption>(std::move(bc));
         }
      } else {
         auto pad = BlockCipherModePaddingMethod::create(padding);
 
         if(pad) {
            if(direction == Cipher_Dir::Encryption) {
               return std::make_unique<CBC_Encryption>(std::move(bc), std::move(pad));
            } else {
               return std::make_unique<CBC_Decryption>(std::move(bc), std::move(pad));
            }
         }
      }
   }
   #endif
 
   #if defined(BOTAN_HAS_MODE_XTS)
   if(spec.algo_name() == "XTS") {
      if(direction == Cipher_Dir::Encryption) {
         return std::make_unique<XTS_Encryption>(std::move(bc));
      } else {
         return std::make_unique<XTS_Decryption>(std::move(bc));
      }
   }
   #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 == Cipher_Dir::Encryption) {
         return std::make_unique<CFB_Encryption>(std::move(bc), feedback_bits);
      } else {
         return std::make_unique<CFB_Decryption>(std::move(bc), feedback_bits);
      }
   }
   #endif
 
#endif
 
   return std::unique_ptr<Cipher_Mode>();
}

References Botan::SCAN_Name::algo_name(), Botan::SCAN_Name::arg(), Botan::SCAN_Name::arg_as_integer(), Botan::SCAN_Name::arg_count(), Botan::AEAD_Mode::create(), Botan::BlockCipher::create(), Botan::BlockCipherModePaddingMethod::create(), create(), Botan::StreamCipher::create(), Botan::Encryption, Botan::make_commoncrypto_cipher_mode(), Botan::parse_algorithm_name(), provider(), and Botan::split_on().

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

create_or_throw()

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

static

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 44 of file cipher_mode.cpp.

                                                                                   {
   if(auto mode = Cipher_Mode::create(algo, direction, provider)) {
      return mode;
   }
 
   throw Lookup_Error("Cipher mode", algo, provider);
}

References create(), and provider().

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

default_nonce_length()

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

pure virtual

Returns

the default size for a nonce

Implemented in Botan::AEAD_Mode, Botan::Ascon_AEAD128_Mode, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, and Botan::XTS_Mode.

finish() [1/2]

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

inline

Complete procession of a message with a final input of buffer, which is treated the same as with update(). If you have the entire message in hand, calling finish() without ever calling update() is both efficient and convenient.

When using an AEAD_Mode, if the supplied authentication tag does not validate, this will throw an instance of Invalid_Authentication_Tag.

If this occurs, all plaintext previously output via calls to update must be destroyed and not used in any way that an attacker could observe the effects of. This could be anything from echoing the plaintext back (perhaps in an error message), or by making an external RPC whose destination or contents depend on the plaintext. The only thing you can do is buffer it, and in the event of an invalid tag, erase the previously decrypted content from memory.

One simple way to assure this could never happen is to never call update, and instead always marshal the entire message into a single buffer and call finish on it when decrypting.

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

Definition at line 178 of file cipher_mode.h.

{ finish_msg(final_block, offset); }

References finish_msg().

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

finish() [2/2]

template<concepts::resizable_byte_buffer T>

void Botan::Cipher_Mode::finish ( T & final_block, size_t offset = 0 )

inline

Complete procession of a message.

Note: Using this overload with anything but a Botan::secure_vector<> is copying the bytes in the in/out buffer.

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

Definition at line 191 of file cipher_mode.h.

                                                     {
         Botan::secure_vector<uint8_t> tmp(final_block.begin(), final_block.end());
         finish_msg(tmp, offset);
         final_block.resize(tmp.size());
         std::copy(tmp.begin(), tmp.end(), final_block.begin());
      }

References finish_msg().

finish_msg()

virtual void Botan::Cipher_Mode::finish_msg ( secure_vector< uint8_t > & final_block, size_t offset = 0 )

protectedpure virtual

Implemented in Botan::TLS::TLS_NULL_HMAC_AEAD_Decryption.

Referenced by finish(), and finish().

has_keying_material()

virtual bool Botan::SymmetricAlgorithm::has_keying_material ( ) const

pure virtualinherited

Returns

true if a key has been set on this object

Implemented in Botan::AES_128, Botan::AES_192, Botan::AES_256, Botan::ANSI_X919_MAC, Botan::ARIA_128, Botan::ARIA_192, Botan::ARIA_256, Botan::Ascon_AEAD128_Mode, Botan::BLAKE2b, Botan::BLAKE2bMAC, Botan::Blowfish, Botan::Camellia_128, Botan::Camellia_192, Botan::Camellia_256, Botan::Cascade_Cipher, Botan::CAST_128, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::ChaCha, Botan::CMAC, Botan::CTR_BE, Botan::DES, Botan::EAX_Mode, Botan::FPE_FE1, Botan::GCM_Mode, Botan::GHASH, Botan::GMAC, Botan::GOST_28147_89, Botan::HMAC, Botan::IDEA, Botan::KMAC, Botan::Kuznyechik, Botan::Lion, Botan::Noekeon, Botan::OCB_Mode, Botan::OFB, Botan::Poly1305, Botan::RC4, Botan::Salsa20, Botan::SEED, Botan::Serpent, Botan::SHACAL2, Botan::SHAKE_Cipher, Botan::SipHash, Botan::SIV_Mode, Botan::SM4, Botan::Threefish_512, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, Botan::TripleDES, Botan::Twofish, and Botan::XTS_Mode.

Referenced by assert_key_material_set(), Botan::TLS::TLS_CBC_HMAC_AEAD_Mode::has_keying_material(), and Botan::TLS::TLS_NULL_HMAC_AEAD_Mode::has_keying_material().

ideal_granularity()

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

pure virtual

Return an ideal granularity. This will be a multiple of the result of update_granularity but may be larger. If so it indicates that better performance may be achieved by providing buffers that are at least that size (due to SIMD execution, etc).

Implemented in Botan::Ascon_AEAD128_Mode, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::EAX_Mode, Botan::GCM_Mode, Botan::OCB_Mode, Botan::SIV_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, and Botan::XTS_Mode.

key_spec()

virtual Key_Length_Specification Botan::SymmetricAlgorithm::key_spec ( ) const

pure virtualinherited

Returns

object describing limits on key size

Implemented in Botan::ANSI_X919_MAC, Botan::Ascon_AEAD128_Mode, Botan::BLAKE2b, Botan::BLAKE2bMAC, Botan::Block_Cipher_Fixed_Params< BS, KMIN, KMAX, KMOD, BaseClass >, Botan::Block_Cipher_Fixed_Params< 16, 16 >, Botan::Block_Cipher_Fixed_Params< 16, 16, 32, 8 >, Botan::Block_Cipher_Fixed_Params< 16, 24 >, Botan::Block_Cipher_Fixed_Params< 16, 32 >, Botan::Block_Cipher_Fixed_Params< 32, 16, 64, 4 >, Botan::Block_Cipher_Fixed_Params< 64, 64, 0, 1, Tweakable_Block_Cipher >, Botan::Block_Cipher_Fixed_Params< 8, 1, 56 >, Botan::Block_Cipher_Fixed_Params< 8, 11, 16 >, Botan::Block_Cipher_Fixed_Params< 8, 16 >, Botan::Block_Cipher_Fixed_Params< 8, 16, 24, 8 >, Botan::Block_Cipher_Fixed_Params< 8, 32 >, Botan::Block_Cipher_Fixed_Params< 8, 8 >, Botan::Cascade_Cipher, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::ChaCha, Botan::CMAC, Botan::CTR_BE, Botan::EAX_Mode, Botan::FPE_FE1, Botan::GCM_Mode, Botan::GHASH, Botan::GMAC, Botan::HMAC, Botan::KMAC, Botan::Lion, Botan::OCB_Mode, Botan::OFB, Botan::Poly1305, Botan::RC4, Botan::Salsa20, Botan::SHAKE_Cipher, Botan::SipHash, Botan::SIV_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, and Botan::XTS_Mode.

Referenced by Botan::CBC_Mode::key_spec(), Botan::CFB_Mode::key_spec(), Botan::XTS_Mode::key_spec(), maximum_keylength(), minimum_keylength(), and valid_keylength().

maximum_keylength()

size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const

inlineinherited

Returns

maximum allowed key length

Definition at line 101 of file sym_algo.h.

{ return key_spec().maximum_keylength(); }

References key_spec().

minimum_final_size()

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

pure virtual

Returns

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

Implemented in Botan::Ascon_AEAD128_Decryption, Botan::Ascon_AEAD128_Encryption, Botan::CBC_Decryption, Botan::CBC_Encryption, Botan::CCM_Decryption, Botan::CCM_Encryption, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Decryption, Botan::ChaCha20Poly1305_Encryption, Botan::CTS_Decryption, Botan::CTS_Encryption, Botan::EAX_Decryption, Botan::EAX_Encryption, Botan::GCM_Decryption, Botan::GCM_Encryption, Botan::OCB_Decryption, Botan::OCB_Encryption, Botan::SIV_Decryption, Botan::SIV_Encryption, Botan::TLS::TLS_CBC_HMAC_AEAD_Decryption, Botan::TLS::TLS_CBC_HMAC_AEAD_Encryption, Botan::TLS::TLS_NULL_HMAC_AEAD_Decryption, Botan::TLS::TLS_NULL_HMAC_AEAD_Encryption, and Botan::XTS_Mode.

minimum_keylength()

size_t Botan::SymmetricAlgorithm::minimum_keylength ( ) const

inlineinherited

Returns

minimum allowed key length

Definition at line 106 of file sym_algo.h.

{ return key_spec().minimum_keylength(); }

References key_spec().

name()

virtual std::string Botan::SymmetricAlgorithm::name ( ) const

pure virtualinherited

Returns

the algorithm name

Implemented in Botan::AES_128, Botan::AES_192, Botan::AES_256, Botan::ANSI_X919_MAC, Botan::ARIA_128, Botan::ARIA_192, Botan::ARIA_256, Botan::Ascon_AEAD128_Mode, Botan::BLAKE2b, Botan::BLAKE2bMAC, Botan::Blowfish, Botan::Camellia_128, Botan::Camellia_192, Botan::Camellia_256, Botan::Cascade_Cipher, Botan::CAST_128, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::ChaCha, Botan::CMAC, Botan::CTR_BE, Botan::DES, Botan::EAX_Mode, Botan::FPE_FE1, Botan::GCM_Mode, Botan::GHASH, Botan::GMAC, Botan::GOST_28147_89, Botan::HMAC, Botan::IDEA, Botan::KMAC128, Botan::KMAC256, Botan::Kuznyechik, Botan::Lion, Botan::Noekeon, Botan::OCB_Mode, Botan::OFB, Botan::Poly1305, Botan::RC4, Botan::Salsa20, Botan::SEED, Botan::Serpent, Botan::SHACAL2, Botan::SHAKE_128_Cipher, Botan::SHAKE_256_Cipher, Botan::SipHash, Botan::SIV_Mode, Botan::SM4, Botan::Threefish_512, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, Botan::TripleDES, Botan::Twofish, and Botan::XTS_Mode.

Referenced by Botan::XTS_Mode::name(), set_key(), and Botan::MessageAuthenticationCode::start_msg().

output_length()

virtual size_t Botan::Cipher_Mode::output_length ( size_t input_length ) const

pure virtual

Returns the size of the output if this transform is used to process a message with input_length bytes. In most cases the answer is precise. If it is not possible to precise (namely for CBC decryption) instead an upper bound is returned.

Implemented in Botan::Ascon_AEAD128_Decryption, Botan::Ascon_AEAD128_Encryption, Botan::CBC_Decryption, Botan::CBC_Encryption, Botan::CCM_Decryption, Botan::CCM_Encryption, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Decryption, Botan::ChaCha20Poly1305_Encryption, Botan::CTS_Encryption, Botan::EAX_Decryption, Botan::EAX_Encryption, Botan::GCM_Decryption, Botan::GCM_Encryption, Botan::OCB_Decryption, Botan::OCB_Encryption, Botan::SIV_Decryption, Botan::SIV_Encryption, Botan::TLS::TLS_CBC_HMAC_AEAD_Decryption, Botan::TLS::TLS_CBC_HMAC_AEAD_Encryption, Botan::TLS::TLS_NULL_HMAC_AEAD_Decryption, Botan::TLS::TLS_NULL_HMAC_AEAD_Encryption, Botan::XTS_Decryption, and Botan::XTS_Encryption.

Referenced by Botan::TLS::TLS_CBC_HMAC_AEAD_Mode::TLS_CBC_HMAC_AEAD_Mode(), Botan::TLS::TLS_NULL_HMAC_AEAD_Mode::TLS_NULL_HMAC_AEAD_Mode(), and Botan::TLS::write_record().

process() [1/2]

size_t Botan::Cipher_Mode::process ( std::span< uint8_t > msg )

inline

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

Returns

bytes written in-place

Definition at line 131 of file cipher_mode.h.

{ return this->process_msg(msg.data(), msg.size()); }

References process_msg().

Referenced by botan_cipher_update(), Botan::TLS::TLS_NULL_HMAC_AEAD_Decryption::finish_msg(), and update().

process() [2/2]

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

inline

Definition at line 133 of file cipher_mode.h.

{ return this->process_msg(msg, msg_len); }

References process_msg().

process_msg()

virtual size_t Botan::Cipher_Mode::process_msg ( uint8_t msg[], size_t msg_len )

protectedpure virtual

Referenced by process(), and process().

provider()

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

inlinevirtual

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 273 of file cipher_mode.h.

{ return "base"; }

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

providers()

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

static

Returns

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

Parameters

algo_spec

algorithm name

Definition at line 171 of file cipher_mode.cpp.

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

References create(), Botan::Encryption, and providers().

Referenced by providers().

requires_entire_message()

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

inlinevirtual

Certain modes require the entire message be available before any processing can occur. For such modes, input will be consumed but not returned, until finish is called, which returns the entire message.

This function returns true if this mode has this style of operation.

Reimplemented in Botan::CCM_Mode, and Botan::SIV_Mode.

Definition at line 232 of file cipher_mode.h.

{ return false; }

Referenced by botan_cipher_update().

reset()

virtual void Botan::Cipher_Mode::reset ( )

pure virtual

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

Implemented in Botan::Ascon_AEAD128_Mode, Botan::CBC_Decryption, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::EAX_Mode, Botan::GCM_Mode, Botan::OCB_Mode, Botan::SIV_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, and Botan::XTS_Mode.

set_key() [1/3]

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

inherited

Set the symmetric key of this object.

Parameters

key	the SymmetricKey to be set.

Definition at line 14 of file sym_algo.cpp.

                                                       {
   set_key(std::span{key.begin(), key.length()});
}

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

Referenced by Botan::create_aes_row_generator(), 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(), Botan::Sphincs_Hash_Functions_Sha2::PRF_msg(), Botan::Sodium::randombytes_buf_deterministic(), Botan::TLS::TLS_NULL_HMAC_AEAD_Mode::reset(), and set_key().

set_key() [2/3]

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

inlineinherited

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 132 of file sym_algo.h.

{ set_key(std::span{key, length}); }

References set_key().

Referenced by set_key().

set_key() [3/3]

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

inherited

Set the symmetric key of this object.

Parameters

key	the contiguous byte range to be set.

Definition at line 22 of file sym_algo.cpp.

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

References name(), and valid_keylength().

start() [1/3]

void Botan::Cipher_Mode::start ( )

inline

Begin processing a message.

The exact semantics of this depend on the mode. For many modes, the call will fail since a nonce must be provided.

For certain modes such as CBC this will instead cause the last ciphertext block to be used as the nonce of the new message; doing this isn't a good idea, but some (mostly older) protocols do this.

Definition at line 116 of file cipher_mode.h.

{ return start_msg(nullptr, 0); }

References start_msg().

start() [2/3]

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

inline

Begin processing a message with a fresh nonce.

Parameters

nonce	the per message nonce
nonce_len	length of nonce

Definition at line 104 of file cipher_mode.h.

{ start_msg(nonce, nonce_len); }

References start_msg().

start() [3/3]

void Botan::Cipher_Mode::start ( std::span< const uint8_t > nonce )

inline

Begin processing a message with a fresh nonce.

Warning

Typically one must not reuse the same nonce for more than one message under the same key. For most cipher modes this would mean total loss of security and/or authenticity guarantees.

Note

If reliably generating unique nonces is difficult in your environment, use SIV which retains security even if nonces are repeated.

Parameters

nonce

the per message nonce

Definition at line 97 of file cipher_mode.h.

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

References start_msg().

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

start_msg()

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

protectedpure virtual

Implemented in Botan::Ascon_AEAD128_Mode.

Referenced by start(), start(), and start().

tag_size()

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

inlinevirtual

Returns

the size of the authentication tag used (in bytes)

Reimplemented in Botan::Ascon_AEAD128_Mode, Botan::CCM_Mode, Botan::ChaCha20Poly1305_Mode, Botan::EAX_Mode, Botan::GCM_Mode, Botan::OCB_Mode, Botan::SIV_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, and Botan::TLS::TLS_NULL_HMAC_AEAD_Mode.

Definition at line 267 of file cipher_mode.h.

{ return 0; }

Referenced by authenticated().

update()

template<concepts::resizable_byte_buffer T>

void Botan::Cipher_Mode::update ( T & buffer, size_t offset = 0 )

inline

Process some data. Input must be in size update_granularity() uint8_t blocks. The buffer is an in/out parameter and may be resized. In particular, some modes require that all input be consumed before any output is produced; with these modes, buffer will be returned empty.

The first offset bytes of buffer will be ignored (this allows in place processing of a buffer that contains an initial plaintext header).

Parameters

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

Definition at line 148 of file cipher_mode.h.

                                                {
         const size_t written = process(std::span(buffer).subspan(offset));
         buffer.resize(offset + written);
      }

References process().

update_granularity()

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

pure virtual

The :cpp:class:Cipher_Mode interface requires message processing in multiples of the block size. This returns size of required blocks to update. If the mode implementation does not require buffering it will return 1.

Returns

size of required blocks to update

Implemented in Botan::Ascon_AEAD128_Mode, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::EAX_Mode, Botan::GCM_Mode, Botan::OCB_Mode, Botan::SIV_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, and Botan::XTS_Mode.

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 113 of file sym_algo.h.

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

References key_spec().

Referenced by set_key().

valid_nonce_length()

virtual bool Botan::Cipher_Mode::valid_nonce_length ( size_t nonce_len ) const

pure virtual

Returns

true iff nonce_len is a valid length for the nonce

Implemented in Botan::Ascon_AEAD128_Mode, Botan::CBC_Mode, Botan::CCM_Mode, Botan::CFB_Mode, Botan::ChaCha20Poly1305_Mode, Botan::CTS_Decryption, Botan::CTS_Encryption, Botan::EAX_Mode, Botan::GCM_Mode, Botan::OCB_Mode, Botan::SIV_Mode, Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, Botan::TLS::TLS_NULL_HMAC_AEAD_Mode, and Botan::XTS_Mode.

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

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