Botan 3.4.0
Crypto and TLS for C&
Public Member Functions | Static Public Member Functions | Protected Member Functions | Protected Attributes | Static Protected Attributes | List of all members
Botan::GCM_Decryption Class Referencefinal

#include <gcm.h>

Inheritance diagram for Botan::GCM_Decryption:
Botan::GCM_Mode Botan::AEAD_Mode Botan::Cipher_Mode Botan::SymmetricAlgorithm

Public Member Functions

virtual bool associated_data_requires_key () const
bool authenticated () const
void clear () override final
size_t default_nonce_length () const override
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)
 GCM_Decryption (std::unique_ptr< BlockCipher > cipher, size_t tag_size=16)
bool has_keying_material () const override final
size_t ideal_granularity () const override final
Key_Length_Specification key_spec () const override final
virtual size_t maximum_associated_data_inputs () const
size_t maximum_keylength () const
size_t minimum_final_size () const override
size_t minimum_keylength () const
std::string name () const override final
size_t output_length (size_t input_length) const override
size_t process (std::span< uint8_t > msg)
size_t process (uint8_t msg[], size_t msg_len)
std::string provider () const override final
virtual bool requires_entire_message () const
void reset () override final
void set_ad (std::span< const uint8_t > ad)
void set_associated_data (const uint8_t ad[], size_t ad_len)
void set_associated_data (std::span< const uint8_t > ad)
void set_associated_data_n (size_t idx, std::span< const uint8_t > ad) override final
template<typename Alloc >
void set_associated_data_vec (const std::vector< uint8_t, Alloc > &ad)
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)
void start ()
void start (const uint8_t nonce[], size_t nonce_len)
void start (std::span< const uint8_t > nonce)
size_t tag_size () const override final
template<concepts::resizable_byte_buffer T>
void update (T &buffer, size_t offset=0)
size_t update_granularity () const override final
bool valid_keylength (size_t length) const
bool valid_nonce_length (size_t len) const override final

Static Public Member Functions

static std::unique_ptr< AEAD_Modecreate (std::string_view algo, Cipher_Dir direction, std::string_view provider="")
static std::unique_ptr< AEAD_Modecreate_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

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 Decryption

Definition at line 93 of file gcm.h.

Constructor & Destructor Documentation

◆ GCM_Decryption()

Botan::GCM_Decryption::GCM_Decryption ( std::unique_ptr< BlockCipher > cipher,
size_t tag_size = 16 )
cipherthe 128 bit block cipher to use
tag_sizeis how big the auth tag will be

Definition at line 99 of file gcm.h.

99 :
100 GCM_Mode(std::move(cipher), tag_size) {}
size_t tag_size() const override final
Definition gcm.h:38
GCM_Mode(std::unique_ptr< BlockCipher > cipher, size_t tag_size)
Definition gcm.cpp:24

Member Function Documentation

◆ assert_key_material_set() [1/2]

void Botan::SymmetricAlgorithm::assert_key_material_set ( ) const

Definition at line 139 of file sym_algo.h.

virtual bool has_keying_material() const =0
void assert_key_material_set() const
Definition sym_algo.h:139

References Botan::SymmetricAlgorithm::assert_key_material_set().

Referenced by Botan::SymmetricAlgorithm::assert_key_material_set(), Botan::Salsa20::cipher_bytes(), Botan::AES_128::decrypt_n(), Botan::AES_192::decrypt_n(), Botan::AES_256::decrypt_n(), Botan::ARIA_128::decrypt_n(), Botan::ARIA_192::decrypt_n(), Botan::ARIA_256::decrypt_n(), Botan::Blowfish::decrypt_n(), Botan::Camellia_128::decrypt_n(), Botan::Camellia_192::decrypt_n(), Botan::Camellia_256::decrypt_n(), Botan::CAST_128::decrypt_n(), Botan::DES::decrypt_n(), Botan::TripleDES::decrypt_n(), Botan::GOST_28147_89::decrypt_n(), Botan::IDEA::decrypt_n(), Botan::Kuznyechik::decrypt_n(), Botan::Lion::decrypt_n(), Botan::Noekeon::decrypt_n(), Botan::SEED::decrypt_n(), Botan::Serpent::decrypt_n(), Botan::SHACAL2::decrypt_n(), Botan::SM4::decrypt_n(), Botan::Threefish_512::decrypt_n(), Botan::Twofish::decrypt_n(), Botan::AES_128::encrypt_n(), Botan::AES_192::encrypt_n(), Botan::AES_256::encrypt_n(), Botan::ARIA_128::encrypt_n(), Botan::ARIA_192::encrypt_n(), Botan::ARIA_256::encrypt_n(), Botan::Blowfish::encrypt_n(), Botan::Camellia_128::encrypt_n(), Botan::Camellia_192::encrypt_n(), Botan::Camellia_256::encrypt_n(), Botan::CAST_128::encrypt_n(), Botan::DES::encrypt_n(), Botan::TripleDES::encrypt_n(), Botan::GOST_28147_89::encrypt_n(), Botan::IDEA::encrypt_n(), Botan::Kuznyechik::encrypt_n(), Botan::Lion::encrypt_n(), Botan::Noekeon::encrypt_n(), Botan::SEED::encrypt_n(), Botan::Serpent::encrypt_n(), Botan::SHACAL2::encrypt_n(), Botan::SM4::encrypt_n(), Botan::Threefish_512::encrypt_n(), Botan::Twofish::encrypt_n(), Botan::GHASH::final(), Botan::GHASH::ghash_update(), Botan::ChaCha::seek(), Botan::CTR_BE::seek(), Botan::Salsa20::seek(), 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

Definition at line 141 of file sym_algo.h.

141 {
142 if(!predicate) {
143 throw_key_not_set_error();
144 }
145 }

◆ associated_data_requires_key()

virtual bool Botan::AEAD_Mode::associated_data_requires_key ( ) const

Most AEADs require the key to be set prior to setting the AD A few allow the AD to be set even before the cipher is keyed. Such ciphers would return false from this function.

Reimplemented in Botan::CCM_Mode, and Botan::ChaCha20Poly1305_Mode.

Definition at line 98 of file aead.h.

98{ return true; }

◆ authenticated()

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

Definition at line 223 of file cipher_mode.h.

223{ return this->tag_size() > 0; }
virtual size_t tag_size() const

◆ clear()

void Botan::GCM_Mode::clear ( )

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 42 of file gcm.cpp.

42 {
43 m_ctr->clear();
44 m_ghash->clear();
45 reset();
std::unique_ptr< GHASH > m_ghash
Definition gcm.h:59
void reset() override final
Definition gcm.cpp:48
std::unique_ptr< StreamCipher > m_ctr
Definition gcm.h:58

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

◆ create()

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

Create an AEAD mode

algothe algorithm to create
directionspecify if this should be an encryption or decryption AEAD
provideroptional specification for provider to use
an AEAD mode or a null pointer if not available

Definition at line 53 of file aead.cpp.

53 {
55#if defined(BOTAN_HAS_AEAD_CHACHA20_POLY1305)
56 if(algo == "ChaCha20Poly1305") {
57 if(dir == Cipher_Dir::Encryption) {
58 return std::make_unique<ChaCha20Poly1305_Encryption>();
59 } else {
60 return std::make_unique<ChaCha20Poly1305_Decryption>();
61 }
62 }
65 if(algo.find('/') != std::string::npos) {
66 const std::vector<std::string> algo_parts = split_on(algo, '/');
67 std::string_view cipher_name = algo_parts[0];
68 const std::vector<std::string> mode_info = parse_algorithm_name(algo_parts[1]);
70 if(mode_info.empty()) {
71 return std::unique_ptr<AEAD_Mode>();
72 }
74 std::ostringstream mode_name;
76 mode_name << mode_info[0] << '(' << cipher_name;
77 for(size_t i = 1; i < mode_info.size(); ++i) {
78 mode_name << ',' << mode_info[i];
79 }
80 for(size_t i = 2; i < algo_parts.size(); ++i) {
81 mode_name << ',' << algo_parts[i];
82 }
83 mode_name << ')';
85 return AEAD_Mode::create(mode_name.str(), dir);
86 }
90 SCAN_Name req(algo);
92 if(req.arg_count() == 0) {
93 return std::unique_ptr<AEAD_Mode>();
94 }
96 auto bc = BlockCipher::create(req.arg(0), provider);
98 if(!bc) {
99 return std::unique_ptr<AEAD_Mode>();
100 }
102 #if defined(BOTAN_HAS_AEAD_CCM)
103 if(req.algo_name() == "CCM") {
104 size_t tag_len = req.arg_as_integer(1, 16);
105 size_t L_len = req.arg_as_integer(2, 3);
106 if(dir == Cipher_Dir::Encryption) {
107 return std::make_unique<CCM_Encryption>(std::move(bc), tag_len, L_len);
108 } else {
109 return std::make_unique<CCM_Decryption>(std::move(bc), tag_len, L_len);
110 }
111 }
112 #endif
114 #if defined(BOTAN_HAS_AEAD_GCM)
115 if(req.algo_name() == "GCM") {
116 size_t tag_len = req.arg_as_integer(1, 16);
117 if(dir == Cipher_Dir::Encryption) {
118 return std::make_unique<GCM_Encryption>(std::move(bc), tag_len);
119 } else {
120 return std::make_unique<GCM_Decryption>(std::move(bc), tag_len);
121 }
122 }
123 #endif
125 #if defined(BOTAN_HAS_AEAD_OCB)
126 if(req.algo_name() == "OCB") {
127 size_t tag_len = req.arg_as_integer(1, 16);
128 if(dir == Cipher_Dir::Encryption) {
129 return std::make_unique<OCB_Encryption>(std::move(bc), tag_len);
130 } else {
131 return std::make_unique<OCB_Decryption>(std::move(bc), tag_len);
132 }
133 }
134 #endif
136 #if defined(BOTAN_HAS_AEAD_EAX)
137 if(req.algo_name() == "EAX") {
138 size_t tag_len = req.arg_as_integer(1, bc->block_size());
139 if(dir == Cipher_Dir::Encryption) {
140 return std::make_unique<EAX_Encryption>(std::move(bc), tag_len);
141 } else {
142 return std::make_unique<EAX_Decryption>(std::move(bc), tag_len);
143 }
144 }
145 #endif
147 #if defined(BOTAN_HAS_AEAD_SIV)
148 if(req.algo_name() == "SIV") {
149 if(dir == Cipher_Dir::Encryption) {
150 return std::make_unique<SIV_Encryption>(std::move(bc));
151 } else {
152 return std::make_unique<SIV_Decryption>(std::move(bc));
153 }
154 }
155 #endif
159 return std::unique_ptr<AEAD_Mode>();
Definition assert.h:118
static std::unique_ptr< AEAD_Mode > create(std::string_view algo, Cipher_Dir direction, std::string_view provider="")
Definition aead.cpp:53
static std::unique_ptr< BlockCipher > create(std::string_view algo_spec, std::string_view provider="")
virtual std::string provider() const
std::vector< std::string > split_on(std::string_view str, char delim)
Definition parsing.cpp:111
std::vector< std::string > parse_algorithm_name(std::string_view namex)
Definition parsing.cpp:57

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

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

◆ create_or_throw()

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

Create an AEAD mode, or throw

algothe algorithm to create
directionspecify if this should be an encryption or decryption AEAD
provideroptional specification for provider to use
an AEAD mode, or throw an exception

Definition at line 43 of file aead.cpp.

45 {
46 if(auto aead = AEAD_Mode::create(algo, dir, provider)) {
47 return aead;
48 }
50 throw Lookup_Error("AEAD", algo, provider);

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

Referenced by Botan::TLS::Cipher_State::advance_with_server_hello(), Botan::TLS::Connection_Cipher_State::Connection_Cipher_State(), Botan::TLS::Session::decrypt(), and Botan::TLS::Session::encrypt().

◆ default_nonce_length()

size_t Botan::AEAD_Mode::default_nonce_length ( ) const
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::CCM_Mode, and Botan::TLS::TLS_CBC_HMAC_AEAD_Mode.

Definition at line 132 of file aead.h.

132{ return 12; }

◆ finish() [1/2]

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

Complete processing of a message.

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

Definition at line 146 of file cipher_mode.h.

146{ finish_msg(final_block, offset); }
virtual void finish_msg(secure_vector< uint8_t > &final_block, size_t offset=0)=0

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 )

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.

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

Definition at line 159 of file cipher_mode.h.

159 {
160 Botan::secure_vector<uint8_t> tmp(final_block.begin(), final_block.end());
161 finish_msg(tmp, offset);
162 final_block.resize(tmp.size());
163 std::copy(tmp.begin(), tmp.end(), final_block.begin());
164 }
std::vector< T, secure_allocator< T > > secure_vector
Definition secmem.h:61

◆ has_keying_material()

bool Botan::GCM_Mode::has_keying_material ( ) const
true if a key has been set on this object

Implements Botan::SymmetricAlgorithm.

Definition at line 77 of file gcm.cpp.

77 {
78 return m_ctr->has_keying_material();

References Botan::GCM_Mode::m_ctr.

◆ ideal_granularity()

size_t Botan::GCM_Mode::ideal_granularity ( ) const

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.

Implements Botan::Cipher_Mode.

Definition at line 64 of file gcm.cpp.

64 {
65 return GCM_BS * std::max<size_t>(2, BOTAN_BLOCK_CIPHER_PAR_MULT);
static const size_t GCM_BS
Definition gcm.h:53
Definition build.h:448

References BOTAN_BLOCK_CIPHER_PAR_MULT, and Botan::GCM_Mode::GCM_BS.

◆ key_spec()

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

Implements Botan::SymmetricAlgorithm.

Definition at line 73 of file gcm.cpp.

73 {
74 return m_ctr->key_spec();

References Botan::GCM_Mode::m_ctr.

◆ maximum_associated_data_inputs()

virtual size_t Botan::AEAD_Mode::maximum_associated_data_inputs ( ) const

Returns the maximum supported number of associated data inputs which can be provided to set_associated_data_n

If returns 0, then no associated data is supported.

Reimplemented in Botan::SIV_Mode.

Definition at line 91 of file aead.h.

91{ return 1; }

◆ maximum_keylength()

size_t Botan::SymmetricAlgorithm::maximum_keylength ( ) const
maximum allowed key length

Definition at line 95 of file sym_algo.h.

95{ return key_spec().maximum_keylength(); }
size_t maximum_keylength() const
Definition sym_algo.h:54
virtual Key_Length_Specification key_spec() const =0

◆ minimum_final_size()

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

Implements Botan::Cipher_Mode.

Definition at line 107 of file gcm.h.

107{ return tag_size(); }

◆ minimum_keylength()

size_t Botan::SymmetricAlgorithm::minimum_keylength ( ) const
minimum allowed key length

Definition at line 100 of file sym_algo.h.

100{ return key_spec().minimum_keylength(); }
size_t minimum_keylength() const
Definition sym_algo.h:49

◆ name()

std::string Botan::GCM_Mode::name ( ) const
the algorithm name

Implements Botan::SymmetricAlgorithm.

Definition at line 52 of file gcm.cpp.

52 {
53 return fmt("{}/GCM({})", m_cipher_name, tag_size());
const std::string m_cipher_name
Definition gcm.h:56
std::string fmt(std::string_view format, const T &... args)
Definition fmt.h:53

References Botan::fmt(), Botan::GCM_Mode::m_cipher_name, and Botan::GCM_Mode::tag_size().

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

◆ output_length()

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

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.

Implements Botan::Cipher_Mode.

Definition at line 102 of file gcm.h.

102 {
103 BOTAN_ARG_CHECK(input_length >= tag_size(), "Sufficient input");
104 return input_length - tag_size();
105 }
#define BOTAN_ARG_CHECK(expr, msg)
Definition assert.h:29


◆ process() [1/2]

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

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).

msgthe message to be processed
bytes written in-place

Definition at line 123 of file cipher_mode.h.

123{ return this->process_msg(, msg.size()); }
virtual size_t process_msg(uint8_t msg[], size_t msg_len)=0

Referenced by botan_cipher_update().

◆ process() [2/2]

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

Definition at line 125 of file cipher_mode.h.

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

◆ provider()

std::string Botan::GCM_Mode::provider ( ) const
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 56 of file gcm.cpp.

56 {
57 return m_ghash->provider();

References Botan::GCM_Mode::m_ghash.

◆ providers()

std::vector< std::string > Botan::Cipher_Mode::providers ( std::string_view algo_spec)
list of available providers for this algorithm, empty if not available
algo_specalgorithm name

Definition at line 164 of file cipher_mode.cpp.

164 {
165 const std::vector<std::string>& possible = {"base", "commoncrypto"};
166 std::vector<std::string> providers;
167 for(auto&& prov : possible) {
168 auto mode = Cipher_Mode::create(algo_spec, Cipher_Dir::Encryption, prov);
169 if(mode) {
170 providers.push_back(prov); // available
171 }
172 }
173 return providers;
static std::unique_ptr< Cipher_Mode > create(std::string_view algo, Cipher_Dir direction, std::string_view provider="")
static std::vector< std::string > providers(std::string_view algo_spec)

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

Referenced by Botan::Cipher_Mode::providers().

◆ requires_entire_message()

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

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 196 of file cipher_mode.h.

196{ return false; }

◆ reset()

void Botan::GCM_Mode::reset ( )

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

Implements Botan::Cipher_Mode.

Definition at line 48 of file gcm.cpp.

48 {
49 m_ghash->reset();

References Botan::GCM_Mode::m_ghash.

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

◆ set_ad()

void Botan::AEAD_Mode::set_ad ( std::span< const uint8_t > ad)

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().

adthe associated data

Definition at line 126 of file aead.h.

126{ set_associated_data(ad); }
void set_associated_data(std::span< const uint8_t > ad)
Definition aead.h:59

◆ set_associated_data() [1/2]

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

Definition at line 61 of file aead.h.

61{ set_associated_data(std::span(ad, ad_len)); }

References Botan::AEAD_Mode::set_associated_data().

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

◆ set_associated_data() [2/2]

void Botan::AEAD_Mode::set_associated_data ( std::span< const uint8_t > ad)

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.

adthe associated data

Definition at line 59 of file aead.h.

59{ set_associated_data_n(0, ad); }
virtual void set_associated_data_n(size_t idx, std::span< const uint8_t > ad)=0

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

◆ set_associated_data_n()

void Botan::GCM_Mode::set_associated_data_n ( size_t idx,
std::span< const uint8_t > ad )

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.

Some AEADs (namely SIV) support multiple AD inputs. For all other modes only nominal AD input 0 is supported; all other values of idx will cause an exception.

Derived AEADs must implement this. For AEADs where maximum_associated_data_inputs() returns 1 (the default), the idx must simply be ignored.

idxwhich associated data to set
adthe associated data

Implements Botan::AEAD_Mode.

Definition at line 92 of file gcm.cpp.

92 {
93 BOTAN_ARG_CHECK(idx == 0, "GCM: cannot handle non-zero index in set_associated_data_n");
94 m_ghash->set_associated_data(ad);

References BOTAN_ARG_CHECK, and Botan::GCM_Mode::m_ghash.

◆ set_associated_data_vec()

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

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().

adthe associated data

Definition at line 111 of file aead.h.

111 {
113 }

◆ set_key() [1/3]

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

◆ set_key() [2/3]

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

Set the symmetric key of this object.

keythe to be set as a byte array.
lengthin bytes of key param

Definition at line 126 of file sym_algo.h.

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

References Botan::SymmetricAlgorithm::set_key().

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

◆ set_key() [3/3]

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

Set the symmetric key of this object.

keythe contiguous byte range to be set.

Definition at line 17 of file sym_algo.cpp.

17 {
18 if(!valid_keylength(key.size())) {
19 throw Invalid_Key_Length(name(), key.size());
20 }
21 key_schedule(key);
bool valid_keylength(size_t length) const
Definition sym_algo.h:107
virtual std::string name() const =0

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

◆ start() [1/3]

void Botan::Cipher_Mode::start ( )

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 108 of file cipher_mode.h.

108{ return start_msg(nullptr, 0); }
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 )

Begin processing a message with a fresh nonce.

noncethe per message nonce
nonce_lenlength of nonce

Definition at line 96 of file cipher_mode.h.

96{ start_msg(nonce, nonce_len); }

◆ start() [3/3]

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

Begin processing a message with a fresh nonce.

noncethe per message nonce

Definition at line 89 of file cipher_mode.h.

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

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

◆ tag_size()

size_t Botan::GCM_Mode::tag_size ( ) const
the size of the authentication tag used (in bytes)

Reimplemented from Botan::Cipher_Mode.

Definition at line 38 of file gcm.h.

38{ return m_tag_size; }
const size_t m_tag_size
Definition gcm.h:55

References Botan::GCM_Mode::m_tag_size.

Referenced by Botan::GCM_Mode::name(), and Botan::GCM_Encryption::output_length().

◆ update()

template<concepts::resizable_byte_buffer T>
void Botan::Cipher_Mode::update ( T & buffer,
size_t offset = 0 )

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

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

Definition at line 133 of file cipher_mode.h.

133 {
134 BOTAN_ASSERT(buffer.size() >= offset, "Offset ok");
135 const size_t written = process(std::span(buffer).subspan(offset));
136 buffer.resize(offset + written);
137 }
#define BOTAN_ASSERT(expr, assertion_made)
Definition assert.h:50
size_t process(std::span< uint8_t > msg)

References BOTAN_ASSERT.

◆ update_granularity()

size_t Botan::GCM_Mode::update_granularity ( ) const
size of required blocks to update

Implements Botan::Cipher_Mode.

Definition at line 60 of file gcm.cpp.

60 {
61 return GCM_BS;

References Botan::GCM_Mode::GCM_BS.

◆ valid_keylength()

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

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

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

Definition at line 107 of file sym_algo.h.

107{ return key_spec().valid_keylength(length); }
bool valid_keylength(size_t length) const
Definition sym_algo.h:42

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

◆ valid_nonce_length()

bool Botan::GCM_Mode::valid_nonce_length ( size_t nonce_len) const
true iff nonce_len is a valid length for the nonce

Implements Botan::Cipher_Mode.

Definition at line 68 of file gcm.cpp.

68 {
69 // GCM does not support empty nonces
70 return (len > 0);

Member Data Documentation


const size_t Botan::GCM_Mode::GCM_BS = 16

◆ m_cipher_name

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

Definition at line 56 of file gcm.h.

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

◆ m_ctr

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

◆ m_ghash

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

◆ m_tag_size

const size_t Botan::GCM_Mode::m_tag_size

Definition at line 55 of file gcm.h.

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

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