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

#include <gcm.h>

Inheritance diagram for Botan::GCM_Encryption:
Botan::GCM_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
 
 GCM_Encryption (BlockCipher *cipher, size_t tag_size=16)
 
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
 
std::string provider () const override
 
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 Attributes

const std::string m_cipher_name
 
std::unique_ptr< StreamCipherm_ctr
 
std::unique_ptr< GHASHm_ghash
 
const size_t m_tag_size
 

Static Protected Attributes

static const size_t GCM_BS = 16
 

Detailed Description

GCM Encryption

Definition at line 66 of file gcm.h.

Constructor & Destructor Documentation

◆ GCM_Encryption()

Botan::GCM_Encryption::GCM_Encryption ( BlockCipher cipher,
size_t  tag_size = 16 
)
inline
Parameters
cipherthe 128 bit block cipher to use
tag_sizeis how big the auth tag will be

Definition at line 73 of file gcm.h.

73  :
74  GCM_Mode(cipher, tag_size) {}
GCM_Mode(BlockCipher *cipher, size_t tag_size)
Definition: gcm.cpp:19
size_t tag_size() const override
Definition: gcm.h:38

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; }

◆ clear()

void Botan::GCM_Mode::clear ( )
overridevirtualinherited

Zeroise all state See also reset_msg()

Implements Botan::Cipher_Mode.

Definition at line 38 of file gcm.cpp.

References Botan::GCM_Mode::m_ctr, Botan::GCM_Mode::m_ghash, and Botan::GCM_Mode::reset().

39  {
40  m_ctr->clear();
41  m_ghash->clear();
42  reset();
43  }
std::unique_ptr< StreamCipher > m_ctr
Definition: gcm.h:55
void reset() override
Definition: gcm.cpp:45
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:56

◆ 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::GCM_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 120 of file gcm.cpp.

References BOTAN_ARG_CHECK, Botan::GCM_Mode::m_ctr, Botan::GCM_Mode::m_ghash, and Botan::GCM_Mode::tag_size().

121  {
122  BOTAN_ARG_CHECK(offset <= buffer.size());
123  const size_t sz = buffer.size() - offset;
124  uint8_t* buf = buffer.data() + offset;
125 
126  m_ctr->cipher(buf, buf, sz);
127  m_ghash->update(buf, sz);
128  auto mac = m_ghash->final();
129  buffer += std::make_pair(mac.data(), tag_size());
130  }
std::unique_ptr< StreamCipher > m_ctr
Definition: gcm.h:55
size_t tag_size() const override
Definition: gcm.h:38
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:56
#define BOTAN_ARG_CHECK(expr)
Definition: exceptn.h:41

◆ key_spec()

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

Implements Botan::Cipher_Mode.

Definition at line 65 of file gcm.cpp.

References Botan::GCM_Mode::GCM_BS, Botan::GCM_Mode::m_ctr, and Botan::GCM_Mode::m_ghash.

66  {
67  return m_ctr->key_spec();
68  }
std::unique_ptr< StreamCipher > m_ctr
Definition: gcm.h:55

◆ minimum_final_size()

size_t Botan::GCM_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 79 of file gcm.h.

79 { return 0; }

◆ name()

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

Implements Botan::Cipher_Mode.

Definition at line 50 of file gcm.cpp.

References Botan::GCM_Mode::m_cipher_name, Botan::GCM_Mode::tag_size(), and Botan::ASN1::to_string().

Referenced by Botan::GCM_Mode::GCM_Mode(), and Botan::GCM_Mode::set_associated_data().

51  {
52  return (m_cipher_name + "/GCM(" + std::to_string(tag_size()) + ")");
53  }
std::string to_string(const BER_Object &obj)
Definition: asn1_obj.cpp:108
const std::string m_cipher_name
Definition: gcm.h:53
size_t tag_size() const override
Definition: gcm.h:38

◆ output_length()

size_t Botan::GCM_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 76 of file gcm.h.

77  { return input_length + tag_size(); }
size_t tag_size() const override
Definition: gcm.h:38

◆ process()

size_t Botan::GCM_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 112 of file gcm.cpp.

References BOTAN_ARG_CHECK, Botan::GCM_Mode::m_ctr, Botan::GCM_Mode::m_ghash, and Botan::GCM_Mode::update_granularity().

113  {
114  BOTAN_ARG_CHECK(sz % update_granularity() == 0);
115  m_ctr->cipher(buf, buf, sz);
116  m_ghash->update(buf, sz);
117  return sz;
118  }
std::unique_ptr< StreamCipher > m_ctr
Definition: gcm.h:55
size_t update_granularity() const override
Definition: gcm.cpp:60
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:56
#define BOTAN_ARG_CHECK(expr)
Definition: exceptn.h:41

◆ provider()

std::string Botan::GCM_Mode::provider ( ) const
overridevirtualinherited
Returns
provider information about this implementation. Default is "base", might also return "sse2", "avx2", "openssl", or some other arbitrary string.

Reimplemented from Botan::Cipher_Mode.

Definition at line 55 of file gcm.cpp.

References Botan::GCM_Mode::m_ghash.

56  {
57  return m_ghash->provider();
58  }
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:56

◆ 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::GCM_Mode::reset ( )
overridevirtualinherited

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

Implements Botan::Cipher_Mode.

Definition at line 45 of file gcm.cpp.

References Botan::GCM_Mode::m_ghash.

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

46  {
47  m_ghash->reset();
48  }
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:56

◆ 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::GCM_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 82 of file gcm.cpp.

References Botan::copy_mem(), Botan::GCM_Mode::GCM_BS, Botan::GCM_Mode::m_ctr, Botan::GCM_Mode::m_ghash, Botan::GCM_Mode::name(), Botan::GCM_Mode::valid_nonce_length(), and Botan::zeroise().

83  {
84  m_ghash->set_associated_data(ad, ad_len);
85  }
std::unique_ptr< GHASH > m_ghash
Definition: gcm.h:56

◆ 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::GCM_Mode::tag_size ( ) const
inlineoverridevirtualinherited
Returns
the size of the authentication tag used (in bytes)

Reimplemented from Botan::Cipher_Mode.

Definition at line 38 of file gcm.h.

Referenced by finish(), Botan::GCM_Decryption::finish(), and Botan::GCM_Mode::name().

38 { return m_tag_size; }
const size_t m_tag_size
Definition: gcm.h:52

◆ 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::GCM_Mode::update_granularity ( ) const
overridevirtualinherited
Returns
size of required blocks to update

Implements Botan::Cipher_Mode.

Definition at line 60 of file gcm.cpp.

References Botan::GCM_Mode::GCM_BS.

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

61  {
62  return GCM_BS;
63  }
static const size_t GCM_BS
Definition: gcm.h:50

◆ 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::GCM_Mode::valid_nonce_length ( size_t  nonce_len) const
inlineoverridevirtualinherited
Returns
true iff nonce_len is a valid length for the nonce

Implements Botan::Cipher_Mode.

Definition at line 36 of file gcm.h.

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

36 { return true; }

Member Data Documentation

◆ GCM_BS

const size_t Botan::GCM_Mode::GCM_BS = 16
staticprotectedinherited

◆ m_cipher_name

const std::string Botan::GCM_Mode::m_cipher_name
protectedinherited

Definition at line 53 of file gcm.h.

Referenced by Botan::GCM_Mode::name().

◆ m_ctr

std::unique_ptr<StreamCipher> Botan::GCM_Mode::m_ctr
protectedinherited

◆ m_ghash

std::unique_ptr<GHASH> Botan::GCM_Mode::m_ghash
protectedinherited

◆ m_tag_size

const size_t Botan::GCM_Mode::m_tag_size
protectedinherited

Definition at line 52 of file gcm.h.

Referenced by Botan::GCM_Mode::GCM_Mode().


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