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

#include <ccm.h>

Inheritance diagram for Botan::CCM_Mode:
Botan::AEAD_Mode Botan::Cipher_Mode Botan::CCM_Decryption Botan::CCM_Encryption

Public Member Functions

bool authenticated () const override
 
void clear () override
 
size_t default_nonce_length () const override
 
virtual void finish (secure_vector< uint8_t > &final_block, size_t offset=0)=0
 
Key_Length_Specification key_spec () const override
 
virtual size_t minimum_final_size () const =0
 
std::string name () const override
 
virtual size_t output_length (size_t input_length) const =0
 
size_t process (uint8_t buf[], size_t sz) 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

const secure_vector< uint8_t > & ad_buf () const
 
 CCM_Mode (BlockCipher *cipher, size_t tag_size, size_t L)
 
const BlockCiphercipher () const
 
void encode_length (size_t len, uint8_t out[])
 
secure_vector< uint8_t > format_b0 (size_t msg_size)
 
secure_vector< uint8_t > format_c0 ()
 
void inc (secure_vector< uint8_t > &C)
 
size_t L () const
 
secure_vector< uint8_t > & msg_buf ()
 

Detailed Description

Base class for CCM encryption and decryption

See also
RFC 3610

Definition at line 21 of file ccm.h.

Constructor & Destructor Documentation

◆ CCM_Mode()

Botan::CCM_Mode::CCM_Mode ( BlockCipher cipher,
size_t  tag_size,
size_t  L 
)
protected

Definition at line 20 of file ccm.cpp.

20  :
21  m_tag_size(tag_size),
22  m_L(L),
23  m_cipher(cipher)
24  {
25  if(m_cipher->block_size() != CCM_BS)
26  throw Invalid_Argument(m_cipher->name() + " cannot be used with CCM mode");
27 
28  if(L < 2 || L > 8)
29  throw Invalid_Argument("Invalid CCM L value " + std::to_string(L));
30 
31  if(tag_size < 4 || tag_size > 16 || tag_size % 2 != 0)
32  throw Invalid_Argument("invalid CCM tag length " + std::to_string(tag_size));
33  }
size_t L() const
Definition: ccm.h:47
const BlockCipher & cipher() const
Definition: ccm.h:49
std::string to_string(const BER_Object &obj)
Definition: asn1_obj.cpp:108
size_t tag_size() const override
Definition: ccm.h:42

Member Function Documentation

◆ ad_buf()

const secure_vector<uint8_t>& Botan::CCM_Mode::ad_buf ( ) const
inlineprotected

Definition at line 55 of file ccm.h.

Referenced by Botan::CCM_Encryption::finish(), and Botan::CCM_Decryption::finish().

55 { return m_ad_buf; }

◆ 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; }

◆ cipher()

const BlockCipher& Botan::CCM_Mode::cipher ( ) const
inlineprotected

Definition at line 49 of file ccm.h.

Referenced by Botan::CCM_Encryption::finish(), and Botan::CCM_Decryption::finish().

49 { return *m_cipher; }

◆ clear()

void Botan::CCM_Mode::clear ( )
overridevirtual

Zeroise all state See also reset_msg()

Implements Botan::Cipher_Mode.

Definition at line 35 of file ccm.cpp.

References reset().

36  {
37  m_cipher->clear();
38  reset();
39  }
void reset() override
Definition: ccm.cpp:41

◆ default_nonce_length()

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

Reimplemented from Botan::AEAD_Mode.

Definition at line 58 of file ccm.cpp.

References L().

59  {
60  return (15-L());
61  }
size_t L() const
Definition: ccm.h:47

◆ encode_length()

void Botan::CCM_Mode::encode_length ( size_t  len,
uint8_t  out[] 
)
protected

Definition at line 116 of file ccm.cpp.

References BOTAN_ASSERT, Botan::get_byte(), and L().

Referenced by format_b0().

117  {
118  const size_t len_bytes = L();
119 
120  BOTAN_ASSERT(len_bytes < sizeof(size_t), "Length field fits");
121 
122  for(size_t i = 0; i != len_bytes; ++i)
123  out[len_bytes-1-i] = get_byte(sizeof(size_t)-1-i, len);
124 
125  BOTAN_ASSERT((len >> (len_bytes*8)) == 0, "Message length fits in field");
126  }
size_t L() const
Definition: ccm.h:47
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:29
uint8_t get_byte(size_t byte_num, T input)
Definition: loadstor.h:39

◆ finish()

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

◆ format_b0()

secure_vector< uint8_t > Botan::CCM_Mode::format_b0 ( size_t  msg_size)
protected

Definition at line 135 of file ccm.cpp.

References Botan::copy_mem(), encode_length(), L(), and tag_size().

Referenced by Botan::CCM_Encryption::finish(), and Botan::CCM_Decryption::finish().

136  {
137  secure_vector<uint8_t> B0(CCM_BS);
138 
139  const uint8_t b_flags =
140  static_cast<uint8_t>((m_ad_buf.size() ? 64 : 0) + (((tag_size()/2)-1) << 3) + (L()-1));
141 
142  B0[0] = b_flags;
143  copy_mem(&B0[1], m_nonce.data(), m_nonce.size());
144  encode_length(sz, &B0[m_nonce.size()+1]);
145 
146  return B0;
147  }
size_t L() const
Definition: ccm.h:47
void encode_length(size_t len, uint8_t out[])
Definition: ccm.cpp:116
void copy_mem(T *out, const T *in, size_t n)
Definition: mem_ops.h:97
size_t tag_size() const override
Definition: ccm.h:42

◆ format_c0()

secure_vector< uint8_t > Botan::CCM_Mode::format_c0 ( )
protected

Definition at line 149 of file ccm.cpp.

References Botan::copy_mem(), and L().

Referenced by Botan::CCM_Encryption::finish(), and Botan::CCM_Decryption::finish().

150  {
151  secure_vector<uint8_t> C(CCM_BS);
152 
153  const uint8_t a_flags = static_cast<uint8_t>(L() - 1);
154 
155  C[0] = a_flags;
156  copy_mem(&C[1], m_nonce.data(), m_nonce.size());
157 
158  return C;
159  }
size_t L() const
Definition: ccm.h:47
void copy_mem(T *out, const T *in, size_t n)
Definition: mem_ops.h:97

◆ inc()

void Botan::CCM_Mode::inc ( secure_vector< uint8_t > &  C)
protected

Definition at line 128 of file ccm.cpp.

Referenced by Botan::CCM_Encryption::finish(), and Botan::CCM_Decryption::finish().

129  {
130  for(size_t i = 0; i != C.size(); ++i)
131  if(++C[C.size()-i-1])
132  break;
133  }

◆ key_spec()

Key_Length_Specification Botan::CCM_Mode::key_spec ( ) const
overridevirtual
Returns
object describing limits on key size

Implements Botan::Cipher_Mode.

Definition at line 74 of file ccm.cpp.

75  {
76  return m_cipher->key_spec();
77  }

◆ L()

size_t Botan::CCM_Mode::L ( ) const
inlineprotected

Definition at line 47 of file ccm.h.

Referenced by default_nonce_length(), encode_length(), format_b0(), format_c0(), name(), and valid_nonce_length().

47 { return m_L; }

◆ minimum_final_size()

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

◆ msg_buf()

secure_vector<uint8_t>& Botan::CCM_Mode::msg_buf ( )
inlineprotected

Definition at line 57 of file ccm.h.

Referenced by Botan::CCM_Encryption::finish(), and Botan::CCM_Decryption::finish().

57 { return m_msg_buf; }

◆ name()

std::string Botan::CCM_Mode::name ( ) const
overridevirtual

Implements Botan::Cipher_Mode.

Definition at line 48 of file ccm.cpp.

References L(), tag_size(), and Botan::ASN1::to_string().

Referenced by set_associated_data().

49  {
50  return (m_cipher->name() + "/CCM(" + std::to_string(tag_size()) + "," + std::to_string(L())) + ")";
51  }
size_t L() const
Definition: ccm.h:47
std::string to_string(const BER_Object &obj)
Definition: asn1_obj.cpp:108
size_t tag_size() const override
Definition: ccm.h:42

◆ output_length()

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

◆ process()

size_t Botan::CCM_Mode::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 110 of file ccm.cpp.

111  {
112  m_msg_buf.insert(m_msg_buf.end(), buf, buf + sz);
113  return 0; // no output until finished
114  }

◆ 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::CCM_Mode::reset ( )
overridevirtual

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

Implements Botan::Cipher_Mode.

Definition at line 41 of file ccm.cpp.

Referenced by clear().

42  {
43  m_nonce.clear();
44  m_msg_buf.clear();
45  m_ad_buf.clear();
46  }

◆ 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::CCM_Mode::set_associated_data ( const uint8_t  ad[],
size_t  ad_len 
)
overridevirtual

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 84 of file ccm.cpp.

References BOTAN_ASSERT, Botan::get_byte(), name(), and valid_nonce_length().

85  {
86  m_ad_buf.clear();
87 
88  if(length)
89  {
90  // FIXME: support larger AD using length encoding rules
91  BOTAN_ASSERT(length < (0xFFFF - 0xFF), "Supported CCM AD length");
92 
93  m_ad_buf.push_back(get_byte(0, static_cast<uint16_t>(length)));
94  m_ad_buf.push_back(get_byte(1, static_cast<uint16_t>(length)));
95  m_ad_buf += std::make_pair(ad, length);
96  while(m_ad_buf.size() % CCM_BS)
97  m_ad_buf.push_back(0); // pad with zeros to full block size
98  }
99  }
#define BOTAN_ASSERT(expr, assertion_made)
Definition: assert.h:29
uint8_t get_byte(size_t byte_num, T input)
Definition: loadstor.h:39

◆ 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::CCM_Mode::tag_size ( ) const
inlineoverridevirtual
Returns
the size of the authentication tag used (in bytes)

Reimplemented from Botan::Cipher_Mode.

Definition at line 42 of file ccm.h.

Referenced by Botan::CCM_Encryption::finish(), Botan::CCM_Decryption::finish(), format_b0(), and name().

42 { 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::CCM_Mode::update_granularity ( ) const
overridevirtual
Returns
size of required blocks to update

Implements Botan::Cipher_Mode.

Definition at line 63 of file ccm.cpp.

64  {
65  /*
66  This value does not particularly matter as regardless CCM_Mode::update
67  buffers all input, so in theory this could be 1. However as for instance
68  Transform_Filter creates update_granularity() uint8_t buffers, use a
69  somewhat large size to avoid bouncing on a tiny buffer.
70  */
71  return m_cipher->parallel_bytes();
72  }

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

Implements Botan::Cipher_Mode.

Definition at line 53 of file ccm.cpp.

References L().

Referenced by set_associated_data().

54  {
55  return (n == (15-L()));
56  }
size_t L() const
Definition: ccm.h:47

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