Botan  1.11.10
Public Member Functions | Protected Member Functions | Protected Attributes | List of all members
Botan::EAX_Decryption Class Reference

#include <eax.h>

Inheritance diagram for Botan::EAX_Decryption:
Botan::EAX_Mode Botan::AEAD_Mode Botan::Cipher_Mode Botan::Keyed_Transform Botan::Transformation

Public Member Functions

bool authenticated () const override
 
void clear () override
 
size_t default_nonce_length () const override
 
 EAX_Decryption (BlockCipher *cipher, size_t tag_size=0)
 
void finish (secure_vector< byte > &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
 
size_t output_length (size_t input_length) const override
 
virtual std::string provider () const
 
void set_associated_data (const byte ad[], size_t ad_len) override
 
template<typename Alloc >
void set_associated_data_vec (const std::vector< byte, Alloc > &ad)
 
template<typename Alloc >
void set_key (const std::vector< byte, Alloc > &key)
 
void set_key (const SymmetricKey &key)
 
void set_key (const byte key[], size_t length)
 
template<typename Alloc >
secure_vector< bytestart (const std::vector< byte, Alloc > &nonce)
 
secure_vector< bytestart (const byte nonce[], size_t nonce_len)
 
secure_vector< bytestart ()
 
template<typename Alloc >
secure_vector< bytestart_vec (const std::vector< byte, Alloc > &nonce)
 
size_t tag_size () const override
 
void update (secure_vector< byte > &blocks, size_t offset=0) override
 
size_t update_granularity () const override
 
bool valid_keylength (size_t length) const
 
bool valid_nonce_length (size_t) const override
 

Protected Member Functions

size_t block_size () const
 

Protected Attributes

secure_vector< bytem_ad_mac
 
std::unique_ptr< BlockCipherm_cipher
 
std::unique_ptr
< MessageAuthenticationCode
m_cmac
 
std::unique_ptr< StreamCipherm_ctr
 
secure_vector< bytem_nonce_mac
 
size_t m_tag_size
 

Detailed Description

EAX Decryption

Definition at line 88 of file eax.h.

Constructor & Destructor Documentation

Botan::EAX_Decryption::EAX_Decryption ( BlockCipher cipher,
size_t  tag_size = 0 
)
inline
Parameters
ciphera 128-bit block cipher
tag_sizeis how big the auth tag will be

Definition at line 95 of file eax.h.

95  :
96  EAX_Mode(cipher, tag_size) {}
EAX_Mode(BlockCipher *cipher, size_t tag_size)
Definition: eax.cpp:38
size_t tag_size() const override
Definition: eax.h:35

Member Function Documentation

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; }
size_t Botan::EAX_Mode::block_size ( ) const
inlineprotectedinherited

Definition at line 45 of file eax.h.

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

45 { return m_cipher->block_size(); }
std::unique_ptr< BlockCipher > m_cipher
Definition: eax.h:49
void Botan::EAX_Mode::clear ( )
overridevirtualinherited

Implements Botan::Transformation.

Definition at line 48 of file eax.cpp.

References Botan::EAX_Mode::m_ad_mac, Botan::EAX_Mode::m_cipher, Botan::EAX_Mode::m_cmac, Botan::EAX_Mode::m_ctr, Botan::EAX_Mode::m_nonce_mac, and Botan::zeroise().

49  {
50  m_cipher.reset();
51  m_ctr.reset();
52  m_cmac.reset();
55  }
std::unique_ptr< BlockCipher > m_cipher
Definition: eax.h:49
secure_vector< byte > m_nonce_mac
Definition: eax.h:55
secure_vector< byte > m_ad_mac
Definition: eax.h:53
std::unique_ptr< MessageAuthenticationCode > m_cmac
Definition: eax.h:51
std::unique_ptr< StreamCipher > m_ctr
Definition: eax.h:50
void zeroise(std::vector< T, Alloc > &vec)
Definition: secmem.h:166
size_t Botan::AEAD_Mode::default_nonce_length ( ) const
inlineoverridevirtualinherited

Default AEAD nonce size (a commonly supported value among AEAD modes, and large enough that random collisions are unlikely).

Implements Botan::Transformation.

Reimplemented in Botan::CCM_Mode.

Definition at line 51 of file aead.h.

51 { return 12; }
void Botan::EAX_Decryption::finish ( secure_vector< byte > &  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::Transformation.

Definition at line 142 of file eax.cpp.

References BOTAN_ASSERT, Botan::EAX_Mode::m_ad_mac, Botan::EAX_Mode::m_cmac, Botan::EAX_Mode::m_ctr, Botan::EAX_Mode::m_nonce_mac, Botan::same_mem(), and Botan::EAX_Mode::tag_size().

143  {
144  BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
145  const size_t sz = buffer.size() - offset;
146  byte* buf = &buffer[offset];
147 
148  BOTAN_ASSERT(sz >= tag_size(), "Have the tag as part of final input");
149 
150  const size_t remaining = sz - tag_size();
151 
152  if(remaining)
153  {
154  m_cmac->update(buf, remaining);
155  m_ctr->cipher(buf, buf, remaining);
156  }
157 
158  const byte* included_tag = &buf[remaining];
159 
160  secure_vector<byte> mac = m_cmac->final();
161  mac ^= m_nonce_mac;
162  mac ^= m_ad_mac;
163 
164  if(!same_mem(&mac[0], included_tag, tag_size()))
165  throw Integrity_Failure("EAX tag check failed");
166 
167  buffer.resize(offset + remaining);
168  }
std::unique_ptr< MessageAuthenticationCode > mac
Definition: fpe_fe1.cpp:89
bool same_mem(const T *p1, const T *p2, size_t n)
Definition: mem_ops.h:63
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:27
uint8_t byte
Definition: types.h:30
secure_vector< byte > m_nonce_mac
Definition: eax.h:55
size_t tag_size() const override
Definition: eax.h:35
secure_vector< byte > m_ad_mac
Definition: eax.h:53
std::unique_ptr< MessageAuthenticationCode > m_cmac
Definition: eax.h:51
std::unique_ptr< StreamCipher > m_ctr
Definition: eax.h:50
Key_Length_Specification Botan::EAX_Mode::key_spec ( ) const
overridevirtualinherited
Returns
object describing limits on key size

Implements Botan::Keyed_Transform.

Definition at line 67 of file eax.cpp.

References Botan::EAX_Mode::m_cipher.

68  {
69  return m_cipher->key_spec();
70  }
std::unique_ptr< BlockCipher > m_cipher
Definition: eax.h:49
size_t Botan::EAX_Decryption::minimum_final_size ( ) const
inlineoverridevirtual
Returns
required minimium size to finalize() - may be any length larger than this.

Implements Botan::Transformation.

Definition at line 104 of file eax.h.

104 { return tag_size(); }
size_t tag_size() const override
Definition: eax.h:35
std::string Botan::EAX_Mode::name ( ) const
overridevirtualinherited

Implements Botan::Transformation.

Definition at line 57 of file eax.cpp.

References Botan::EAX_Mode::m_cipher.

Referenced by Botan::EAX_Mode::EAX_Mode().

58  {
59  return (m_cipher->name() + "/EAX");
60  }
std::unique_ptr< BlockCipher > m_cipher
Definition: eax.h:49
size_t Botan::EAX_Decryption::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::Transformation.

Definition at line 98 of file eax.h.

References BOTAN_ASSERT.

99  {
100  BOTAN_ASSERT(input_length > tag_size(), "Sufficient input");
101  return input_length - tag_size();
102  }
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:27
size_t tag_size() const override
Definition: eax.h:35
virtual std::string Botan::Transformation::provider ( ) const
inlinevirtualinherited

Return some short name describing the provider of this tranformation. Useful in cases where multiple implementations are available (eg, different implementations of AES). Default "core" is used for the 'standard' implementation included in the library.

Definition at line 117 of file transform.h.

117 { return "core"; }
void Botan::EAX_Mode::set_associated_data ( const byte  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 finish.

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 90 of file eax.cpp.

References Botan::EAX_Mode::block_size(), Botan::EAX_Mode::m_ad_mac, and Botan::EAX_Mode::m_cmac.

91  {
92  m_ad_mac = eax_prf(1, block_size(), *m_cmac, ad, length);
93  }
size_t block_size() const
Definition: eax.h:45
secure_vector< byte > m_ad_mac
Definition: eax.h:53
std::unique_ptr< MessageAuthenticationCode > m_cmac
Definition: eax.h:51
template<typename Alloc >
void Botan::AEAD_Mode::set_associated_data_vec ( const std::vector< byte, Alloc > &  ad)
inlineinherited

Definition at line 42 of file aead.h.

43  {
44  set_associated_data(&ad[0], ad.size());
45  }
virtual void set_associated_data(const byte ad[], size_t ad_len)=0
template<typename Alloc >
void Botan::Keyed_Transform::set_key ( const std::vector< byte, Alloc > &  key)
inlineinherited

Definition at line 145 of file transform.h.

146  {
147  set_key(&key[0], key.size());
148  }
void set_key(const std::vector< byte, Alloc > &key)
Definition: transform.h:145
void Botan::Keyed_Transform::set_key ( const SymmetricKey key)
inlineinherited

Definition at line 150 of file transform.h.

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

151  {
152  set_key(key.begin(), key.length());
153  }
void set_key(const std::vector< byte, Alloc > &key)
Definition: transform.h:145
void Botan::Keyed_Transform::set_key ( const byte  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 160 of file transform.h.

161  {
162  if(!valid_keylength(length))
163  throw Invalid_Key_Length(name(), length);
164  key_schedule(key, length);
165  }
virtual std::string name() const =0
bool valid_keylength(size_t length) const
Definition: transform.h:139
template<typename Alloc >
secure_vector<byte> Botan::Transformation::start ( const std::vector< byte, Alloc > &  nonce)
inlineinherited

Begin processing a message.

Parameters
noncethe per message nonce

Definition at line 31 of file transform.h.

32  {
33  return start(&nonce[0], nonce.size());
34  }
secure_vector< byte > start()
Definition: transform.h:60
secure_vector<byte> Botan::Transformation::start ( const byte  nonce[],
size_t  nonce_len 
)
inlineinherited

Begin processing a message.

Parameters
noncethe per message nonce
nonce_lenlength of nonce

Definition at line 52 of file transform.h.

53  {
54  return start_raw(nonce, nonce_len);
55  }
virtual secure_vector< byte > start_raw(const byte nonce[], size_t nonce_len)=0
secure_vector<byte> Botan::Transformation::start ( )
inlineinherited

Begin processing a message.

Definition at line 60 of file transform.h.

61  {
62  return start_raw(nullptr, 0);
63  }
virtual secure_vector< byte > start_raw(const byte nonce[], size_t nonce_len)=0
template<typename Alloc >
secure_vector<byte> Botan::Transformation::start_vec ( const std::vector< byte, Alloc > &  nonce)
inlineinherited

Begin processing a message.

Parameters
noncethe per message nonce

Definition at line 42 of file transform.h.

43  {
44  return start(&nonce[0], nonce.size());
45  }
secure_vector< byte > start()
Definition: transform.h:60
size_t Botan::EAX_Mode::tag_size ( ) const
inlineoverridevirtualinherited

Return the size of the authentication tag used (in bytes)

Implements Botan::AEAD_Mode.

Definition at line 35 of file eax.h.

Referenced by Botan::EAX_Encryption::finish(), and finish().

35 { return m_tag_size; }
size_t m_tag_size
Definition: eax.h:47
void Botan::EAX_Decryption::update ( secure_vector< byte > &  blocks,
size_t  offset = 0 
)
overridevirtual

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

Parameters
blocksin/out paramter which will possibly be resized
offsetan offset into blocks to begin processing

Implements Botan::Transformation.

Definition at line 132 of file eax.cpp.

References BOTAN_ASSERT, Botan::EAX_Mode::m_cmac, and Botan::EAX_Mode::m_ctr.

133  {
134  BOTAN_ASSERT(buffer.size() >= offset, "Offset is sane");
135  const size_t sz = buffer.size() - offset;
136  byte* buf = &buffer[offset];
137 
138  m_cmac->update(buf, sz);
139  m_ctr->cipher(buf, buf, sz);
140  }
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:27
uint8_t byte
Definition: types.h:30
std::unique_ptr< MessageAuthenticationCode > m_cmac
Definition: eax.h:51
std::unique_ptr< StreamCipher > m_ctr
Definition: eax.h:50
size_t Botan::EAX_Mode::update_granularity ( ) const
overridevirtualinherited
Returns
size of required blocks to update

Implements Botan::Transformation.

Definition at line 62 of file eax.cpp.

References Botan::EAX_Mode::m_cipher.

63  {
64  return 8 * m_cipher->parallel_bytes();
65  }
std::unique_ptr< BlockCipher > m_cipher
Definition: eax.h:49
bool Botan::Keyed_Transform::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 139 of file transform.h.

140  {
141  return key_spec().valid_keylength(length);
142  }
bool valid_keylength(size_t length) const
Definition: key_spec.h:51
virtual Key_Length_Specification key_spec() const =0
bool Botan::EAX_Mode::valid_nonce_length ( size_t  nonce_len) const
inlineoverridevirtualinherited

Return true iff nonce_len is a valid length for the nonce

Implements Botan::Transformation.

Definition at line 33 of file eax.h.

33 { return true; }

Member Data Documentation

secure_vector<byte> Botan::EAX_Mode::m_ad_mac
protectedinherited
std::unique_ptr<BlockCipher> Botan::EAX_Mode::m_cipher
protectedinherited
std::unique_ptr<MessageAuthenticationCode> Botan::EAX_Mode::m_cmac
protectedinherited
std::unique_ptr<StreamCipher> Botan::EAX_Mode::m_ctr
protectedinherited

Definition at line 50 of file eax.h.

Referenced by Botan::EAX_Mode::clear(), finish(), Botan::EAX_Encryption::update(), and update().

secure_vector<byte> Botan::EAX_Mode::m_nonce_mac
protectedinherited

Definition at line 55 of file eax.h.

Referenced by Botan::EAX_Mode::clear(), Botan::EAX_Encryption::finish(), and finish().

size_t Botan::EAX_Mode::m_tag_size
protectedinherited

Definition at line 47 of file eax.h.


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