Botan  2.4.0
Crypto and TLS for C++11
Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
Botan::OCB_Encryption Class Referencefinal

#include <ocb.h>

Inheritance diagram for Botan::OCB_Encryption:
Botan::OCB_Mode Botan::AEAD_Mode Botan::Cipher_Mode

Public Member Functions

bool authenticated () const override
 
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
 
 OCB_Encryption (BlockCipher *cipher, size_t tag_size=16)
 
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_ad (const std::vector< uint8_t, Alloc > &ad)
 
void set_associated_data (const uint8_t ad[], size_t ad_len) override
 
template<typename Alloc >
void set_associated_data_vec (const std::vector< uint8_t, Alloc > &ad)
 
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 ()
 
size_t tag_size () const override
 
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) const override
 

Static Public Member Functions

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

Protected Member Functions

size_t block_size () const
 
size_t par_blocks () const
 
size_t par_bytes () const
 

Protected Attributes

secure_vector< uint8_t > m_ad_hash
 
size_t m_block_index = 0
 
secure_vector< uint8_t > m_checksum
 
std::unique_ptr< BlockCipherm_cipher
 
std::unique_ptr< L_computer > m_L
 

Detailed Description

Definition at line 84 of file ocb.h.

Constructor & Destructor Documentation

◆ OCB_Encryption()

Botan::OCB_Encryption::OCB_Encryption ( BlockCipher cipher,
size_t  tag_size = 16 
)
inline
Parameters
cipherthe block cipher to use
tag_sizeis how big the auth tag will be

Definition at line 91 of file ocb.h.

91  :
92  OCB_Mode(cipher, tag_size) {}
size_t tag_size() const override
Definition: ocb.h:44
OCB_Mode(BlockCipher *cipher, size_t tag_size)
Definition: ocb.cpp:159

Member Function Documentation

◆ authenticated()

bool Botan::AEAD_Mode::authenticated ( ) const
inlineoverridevirtualinherited
Returns
true iff this mode provides authentication as well as confidentiality.

Reimplemented from Botan::Cipher_Mode.

Definition at line 25 of file aead.h.

25 { return true; }

◆ block_size()

size_t Botan::OCB_Mode::block_size ( ) const
inlineprotectedinherited

◆ clear()

void Botan::OCB_Mode::clear ( )
overridevirtualinherited

Zeroise all state See also reset_msg()

Implements Botan::Cipher_Mode.

Definition at line 183 of file ocb.cpp.

References Botan::OCB_Mode::m_cipher, Botan::OCB_Mode::m_L, and Botan::OCB_Mode::reset().

184  {
185  m_cipher->clear();
186  m_L.reset(); // add clear here?
187  reset();
188  }
std::unique_ptr< BlockCipher > m_cipher
Definition: ocb.h:63
void reset() override
Definition: ocb.cpp:190
std::unique_ptr< L_computer > m_L
Definition: ocb.h:64

◆ default_nonce_length()

size_t Botan::AEAD_Mode::default_nonce_length ( ) const
inlineoverridevirtualinherited
Returns
default AEAD nonce size (a commonly supported value among AEAD modes, and large enough that random collisions are unlikely)

Implements Botan::Cipher_Mode.

Reimplemented in Botan::TLS::TLS_CBC_HMAC_AEAD_Mode, and Botan::CCM_Mode.

Definition at line 75 of file aead.h.

References BOTAN_PUBLIC_API, and Botan::get_aead().

75 { return 12; }

◆ finish()

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

Complete processing of a message.

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

Implements Botan::Cipher_Mode.

Definition at line 369 of file ocb.cpp.

References Botan::OCB_Mode::block_size(), BOTAN_ASSERT, Botan::CryptoBox::encrypt(), Botan::OCB_Mode::m_ad_hash, Botan::OCB_Mode::m_block_index, Botan::OCB_Mode::m_checksum, Botan::OCB_Mode::m_cipher, Botan::OCB_Mode::m_L, Botan::OCB_Mode::par_blocks(), Botan::OCB_Mode::tag_size(), Botan::xor_buf(), and Botan::zeroise().

370  {
371  const size_t BS = block_size();
372 
373  BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
374  const size_t sz = buffer.size() - offset;
375  uint8_t* buf = buffer.data() + offset;
376 
377  secure_vector<uint8_t> mac(BS);
378 
379  if(sz)
380  {
381  const size_t final_full_blocks = sz / BS;
382  const size_t remainder_bytes = sz - (final_full_blocks * BS);
383 
384  encrypt(buf, final_full_blocks);
385  mac = m_L->offset();
386 
387  if(remainder_bytes)
388  {
389  BOTAN_ASSERT(remainder_bytes < BS, "Only a partial block left");
390  uint8_t* remainder = &buf[sz - remainder_bytes];
391 
392  xor_buf(m_checksum.data(), remainder, remainder_bytes);
393  m_checksum[remainder_bytes] ^= 0x80;
394 
395  // Offset_*
396  mac ^= m_L->star();
397 
398  secure_vector<uint8_t> pad(BS);
399  m_cipher->encrypt(mac, pad);
400  xor_buf(remainder, pad.data(), remainder_bytes);
401  }
402  }
403  else
404  {
405  mac = m_L->offset();
406  }
407 
408  // now compute the tag
409 
410  // fold checksum
411  for(size_t i = 0; i != m_checksum.size(); i += BS)
412  {
413  xor_buf(mac.data(), m_checksum.data() + i, BS);
414  }
415 
416  xor_buf(mac.data(), m_L->dollar().data(), BS);
417  m_cipher->encrypt(mac);
418  xor_buf(mac.data(), m_ad_hash.data(), BS);
419 
420  buffer += std::make_pair(mac.data(), tag_size());
421 
422  zeroise(m_checksum);
423  m_block_index = 0;
424  }
std::unique_ptr< BlockCipher > m_cipher
Definition: ocb.h:63
size_t tag_size() const override
Definition: ocb.h:44
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:29
void xor_buf(uint8_t out[], const uint8_t in[], size_t length)
Definition: mem_ops.h:163
std::unique_ptr< L_computer > m_L
Definition: ocb.h:64
size_t block_size() const
Definition: ocb.h:58
secure_vector< uint8_t > m_ad_hash
Definition: ocb.h:69
secure_vector< uint8_t > m_checksum
Definition: ocb.h:68
size_t m_block_index
Definition: ocb.h:66
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:181

◆ key_spec()

Key_Length_Specification Botan::OCB_Mode::key_spec ( ) const
overridevirtualinherited
Returns
object describing limits on key size

Implements Botan::Cipher_Mode.

Definition at line 219 of file ocb.cpp.

References Botan::OCB_Mode::m_cipher, and Botan::OCB_Mode::m_L.

220  {
221  return m_cipher->key_spec();
222  }
std::unique_ptr< BlockCipher > m_cipher
Definition: ocb.h:63

◆ minimum_final_size()

size_t Botan::OCB_Encryption::minimum_final_size ( ) const
inlineoverridevirtual
Returns
required minimium size to finalize() - may be any length larger than this.

Implements Botan::Cipher_Mode.

Definition at line 97 of file ocb.h.

References Botan::CryptoBox::encrypt().

97 { return 0; }

◆ name()

std::string Botan::OCB_Mode::name ( ) const
overridevirtualinherited

Implements Botan::Cipher_Mode.

Definition at line 209 of file ocb.cpp.

References Botan::OCB_Mode::m_cipher.

Referenced by Botan::OCB_Mode::set_associated_data().

210  {
211  return m_cipher->name() + "/OCB"; // include tag size?
212  }
std::unique_ptr< BlockCipher > m_cipher
Definition: ocb.h:63

◆ output_length()

size_t Botan::OCB_Encryption::output_length ( size_t  input_length) const
inlineoverridevirtual

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.

Definition at line 94 of file ocb.h.

95  { return input_length + tag_size(); }
size_t tag_size() const override
Definition: ocb.h:44

◆ par_blocks()

size_t Botan::OCB_Mode::par_blocks ( ) const
inlineprotectedinherited

Definition at line 59 of file ocb.h.

Referenced by finish(), and Botan::OCB_Mode::set_associated_data().

59 { return m_par_blocks; }

◆ par_bytes()

size_t Botan::OCB_Mode::par_bytes ( ) const
inlineprotectedinherited

Definition at line 60 of file ocb.h.

60 { return m_checksum.size(); }
secure_vector< uint8_t > m_checksum
Definition: ocb.h:68

◆ process()

size_t Botan::OCB_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
msgthe message to be processed
msg_lenlength of the message in bytes

Implements Botan::Cipher_Mode.

Definition at line 362 of file ocb.cpp.

References Botan::OCB_Mode::block_size(), BOTAN_ASSERT, Botan::CryptoBox::encrypt(), and Botan::OCB_Mode::update_granularity().

363  {
364  BOTAN_ASSERT(sz % update_granularity() == 0, "Invalid OCB input size");
365  encrypt(buf, sz / block_size());
366  return sz;
367  }
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:29
size_t update_granularity() const override
Definition: ocb.cpp:214
size_t block_size() const
Definition: ocb.h:58

◆ 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 208 of file cipher_mode.h.

208 { 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_specalgorithm name

Definition at line 158 of file cipher_mode.cpp.

References Botan::ENCRYPTION, and Botan::get_cipher_mode().

159  {
160  const std::vector<std::string>& possible = { "base", "openssl" };
161  std::vector<std::string> providers;
162  for(auto&& prov : possible)
163  {
164  std::unique_ptr<Cipher_Mode> mode(get_cipher_mode(algo_spec, ENCRYPTION, prov));
165  if(mode)
166  {
167  providers.push_back(prov); // available
168  }
169  }
170  return providers;
171  }
Cipher_Mode * get_cipher_mode(const std::string &algo, Cipher_Dir direction, const std::string &provider)
Definition: cipher_mode.cpp:40
static std::vector< std::string > providers(const std::string &algo_spec)

◆ reset()

void Botan::OCB_Mode::reset ( )
overridevirtualinherited

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

Implements Botan::Cipher_Mode.

Definition at line 190 of file ocb.cpp.

References Botan::OCB_Mode::m_ad_hash, Botan::OCB_Mode::m_block_index, Botan::OCB_Mode::m_checksum, and Botan::zeroise().

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

191  {
192  m_block_index = 0;
195  m_last_nonce.clear();
196  m_stretch.clear();
197  }
secure_vector< uint8_t > m_ad_hash
Definition: ocb.h:69
secure_vector< uint8_t > m_checksum
Definition: ocb.h:68
size_t m_block_index
Definition: ocb.h:66
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:181

◆ set_ad()

template<typename Alloc >
void Botan::AEAD_Mode::set_ad ( const std::vector< uint8_t, Alloc > &  ad)
inlineinherited

Set associated data that is not included in the ciphertext but that should be authenticated. Must be called after set_key and before start.

See set_associated_data().

Parameters
adthe associated data

Definition at line 66 of file aead.h.

Referenced by Botan::TLS::write_record().

67  {
68  set_associated_data(ad.data(), ad.size());
69  }
virtual void set_associated_data(const uint8_t ad[], size_t ad_len)=0

◆ set_associated_data()

void Botan::OCB_Mode::set_associated_data ( const uint8_t  ad[],
size_t  ad_len 
)
overridevirtualinherited

Set associated data that is not included in the ciphertext but that should be authenticated. Must be called after set_key and before start.

Unless reset by another call, the associated data is kept between messages. Thus, if the AD does not change, calling once (after set_key) is the optimum.

Parameters
adthe associated data
ad_lenlength of add in bytes

Implements Botan::AEAD_Mode.

Definition at line 230 of file ocb.cpp.

References Botan::OCB_Mode::block_size(), BOTAN_ASSERT, Botan::copy_mem(), Botan::OCB_Mode::m_ad_hash, Botan::OCB_Mode::m_block_index, Botan::OCB_Mode::m_checksum, Botan::OCB_Mode::m_cipher, Botan::OCB_Mode::m_L, Botan::OCB_Mode::name(), Botan::OCB_Mode::par_blocks(), Botan::OCB_Mode::tag_size(), Botan::OCB_Mode::valid_nonce_length(), Botan::xor_buf(), and Botan::zeroise().

231  {
232  BOTAN_ASSERT(m_L, "A key was set");
233  m_ad_hash = ocb_hash(*m_L, *m_cipher, ad, ad_len);
234  }
std::unique_ptr< BlockCipher > m_cipher
Definition: ocb.h:63
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:29
std::unique_ptr< L_computer > m_L
Definition: ocb.h:64
secure_vector< uint8_t > m_ad_hash
Definition: ocb.h:69

◆ set_associated_data_vec()

template<typename Alloc >
void Botan::AEAD_Mode::set_associated_data_vec ( const std::vector< uint8_t, Alloc > &  ad)
inlineinherited

Set associated data that is not included in the ciphertext but that should be authenticated. Must be called after set_key and before start.

See set_associated_data().

Parameters
adthe associated data

Definition at line 51 of file aead.h.

Referenced by Botan::TLS::write_record().

52  {
53  set_associated_data(ad.data(), ad.size());
54  }
virtual void set_associated_data(const uint8_t ad[], size_t ad_len)=0

◆ 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
keycontains the key material

Definition at line 178 of file cipher_mode.h.

Referenced by botan_cipher_set_key(), and Botan::TLS::TLS_CBC_HMAC_AEAD_Mode::key_spec().

179  {
180  set_key(key.data(), key.size());
181  }
void set_key(const std::vector< uint8_t, Alloc > &key)
Definition: cipher_mode.h:178

◆ set_key() [2/3]

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

Set the symmetric key of this transform

Parameters
keycontains the key material

Definition at line 187 of file cipher_mode.h.

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

188  {
189  set_key(key.begin(), key.length());
190  }
void set_key(const std::vector< uint8_t, Alloc > &key)
Definition: cipher_mode.h:178

◆ 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
keycontains the key material
lengthin bytes of key param

Definition at line 197 of file cipher_mode.h.

198  {
199  if(!valid_keylength(length))
200  throw Invalid_Key_Length(name(), length);
201  key_schedule(key, length);
202  }
virtual std::string name() const =0
bool valid_keylength(size_t length) const
Definition: cipher_mode.h:168

◆ start() [1/3]

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

Begin processing a message.

Parameters
noncethe per message nonce

Definition at line 44 of file cipher_mode.h.

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

45  {
46  start_msg(nonce.data(), nonce.size());
47  }
virtual void start_msg(const uint8_t nonce[], size_t nonce_len)=0

◆ start() [2/3]

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

Begin processing a message.

Parameters
noncethe per message nonce
nonce_lenlength of nonce

Definition at line 54 of file cipher_mode.h.

55  {
56  start_msg(nonce, nonce_len);
57  }
virtual void start_msg(const uint8_t nonce[], size_t nonce_len)=0

◆ start() [3/3]

void Botan::Cipher_Mode::start ( )
inlineinherited

Begin processing a message.

Definition at line 62 of file cipher_mode.h.

63  {
64  return start_msg(nullptr, 0);
65  }
virtual void start_msg(const uint8_t nonce[], size_t nonce_len)=0

◆ tag_size()

size_t Botan::OCB_Mode::tag_size ( ) const
inlineoverridevirtualinherited
Returns
the size of the authentication tag used (in bytes)

Reimplemented from Botan::Cipher_Mode.

Definition at line 44 of file ocb.h.

Referenced by finish(), Botan::OCB_Decryption::finish(), and Botan::OCB_Mode::set_associated_data().

44 { return m_tag_size; }

◆ 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
bufferin/out parameter which will possibly be resized
offsetan offset into blocks to begin processing

Definition at line 87 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(), Botan::CBC_Encryption::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().

88  {
89  BOTAN_ASSERT(buffer.size() >= offset, "Offset ok");
90  uint8_t* buf = buffer.data() + offset;
91  const size_t buf_size = buffer.size() - offset;
92 
93  const size_t written = process(buf, buf_size);
94  buffer.resize(offset + written);
95  }
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:29
virtual size_t process(uint8_t msg[], size_t msg_len)=0

◆ update_granularity()

size_t Botan::OCB_Mode::update_granularity ( ) const
overridevirtualinherited
Returns
size of required blocks to update

Implements Botan::Cipher_Mode.

Definition at line 214 of file ocb.cpp.

References Botan::OCB_Mode::block_size().

Referenced by process(), and Botan::OCB_Decryption::process().

215  {
216  return (m_par_blocks * block_size());
217  }
size_t block_size() const
Definition: ocb.h:58

◆ 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
lengththe key length to be checked.
Returns
true if the key length is valid.

Definition at line 168 of file cipher_mode.h.

169  {
170  return key_spec().valid_keylength(length);
171  }
virtual Key_Length_Specification key_spec() const =0
bool valid_keylength(size_t length) const
Definition: key_spec.h:51

◆ valid_nonce_length()

bool Botan::OCB_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.

Definition at line 199 of file ocb.cpp.

References Botan::OCB_Mode::block_size().

Referenced by Botan::OCB_Mode::set_associated_data().

200  {
201  if(length == 0)
202  return false;
203  if(block_size() == 16)
204  return length < 16;
205  else
206  return length < (block_size() - 1);
207  }
size_t block_size() const
Definition: ocb.h:58

Member Data Documentation

◆ m_ad_hash

secure_vector<uint8_t> Botan::OCB_Mode::m_ad_hash
protectedinherited

◆ m_block_index

size_t Botan::OCB_Mode::m_block_index = 0
protectedinherited

◆ m_checksum

secure_vector<uint8_t> Botan::OCB_Mode::m_checksum
protectedinherited

◆ m_cipher

std::unique_ptr<BlockCipher> Botan::OCB_Mode::m_cipher
protectedinherited

◆ m_L

std::unique_ptr<L_computer> Botan::OCB_Mode::m_L
protectedinherited

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