12#include <botan/internal/mce_internal.h>
13#include <botan/mceliece.h>
14#include <botan/internal/code_based_util.h>
15#include <botan/internal/bit_ops.h>
21secure_vector<uint8_t> concat_vectors(
const secure_vector<uint8_t>& a,
22 const secure_vector<uint8_t>& b,
28 const size_t final_bits = dimension % 8;
33 copy_mem(&x[0], a.data(), dim_bytes);
38 copy_mem(&x[0], a.data(), (dimension / 8));
39 size_t l = dimension / 8;
40 x[l] =
static_cast<uint8_t
>(a[l] & ((1 << final_bits) - 1));
42 for(
size_t k = 0; k < codimension / 8; ++k)
44 x[l] ^=
static_cast<uint8_t
>(b[k] << final_bits);
46 x[l] =
static_cast<uint8_t
>(b[k] >> (8 - final_bits));
48 x[l] ^=
static_cast<uint8_t
>(b[codimension/8] << final_bits);
54secure_vector<uint8_t> mult_by_pubkey(
const secure_vector<uint8_t>& cleartext,
55 std::vector<uint8_t>
const& public_matrix,
56 size_t code_length,
size_t t)
58 const size_t ext_deg =
ceil_log2(code_length);
59 const size_t codimension = ext_deg * t;
60 const size_t dimension = code_length - codimension;
63 const uint8_t* pt = public_matrix.data();
65 for(
size_t i = 0; i < dimension / 8; ++i)
67 for(
size_t j = 0; j < 8; ++j)
69 if(cleartext[i] & (1 << j))
71 xor_buf(cR.data(), pt, cR.size());
77 for(
size_t i = 0; i < dimension % 8 ; ++i)
79 if(cleartext[dimension/8] & (1 << i))
81 xor_buf(cR.data(), pt, cR.size());
86 secure_vector<uint8_t> ciphertext = concat_vectors(cleartext, cR, dimension, codimension);
87 ciphertext.resize((code_length+7)/8);
91secure_vector<uint8_t> create_random_error_vector(
size_t code_length,
93 RandomNumberGenerator& rng)
95 secure_vector<uint8_t> result((code_length+7)/8);
99 while(bits_set < error_weight)
103 const size_t byte_pos = x / 8;
104 const size_t bit_pos = x % 8;
106 const uint8_t mask = (1 << bit_pos);
108 if(result[byte_pos] & mask)
111 result[byte_pos] |= mask;
126 const uint16_t code_length =
static_cast<uint16_t
>(key.
get_code_length());
133 ciphertext ^= error_mask;
135 ciphertext_out.swap(ciphertext);
136 error_mask_out.swap(error_mask);
const std::vector< uint8_t > & get_public_matrix() const
size_t get_code_length() const
void mceliece_encrypt(secure_vector< uint8_t > &ciphertext_out, secure_vector< uint8_t > &error_mask_out, const secure_vector< uint8_t > &plaintext, const McEliece_PublicKey &key, RandomNumberGenerator &rng)
gf2m random_code_element(uint16_t code_length, RandomNumberGenerator &rng)
constexpr void copy_mem(T *out, const T *in, size_t n)
void xor_buf(uint8_t out[], const uint8_t in[], size_t length)
size_t bit_size_to_32bit_size(size_t bit_size)
size_t bit_size_to_byte_size(size_t bit_size)
std::vector< T, secure_allocator< T > > secure_vector
constexpr uint8_t ceil_log2(T x)