10#include <botan/hash.h>
11#include <botan/internal/loadstor.h>
18const size_t RTSS_HEADER_SIZE = 20;
23alignas(64)
const uint8_t RTSS_EXP[256] = {
240x01, 0x03, 0x05, 0x0F, 0x11, 0x33, 0x55, 0xFF, 0x1A, 0x2E, 0x72,
250x96, 0xA1, 0xF8, 0x13, 0x35, 0x5F, 0xE1, 0x38, 0x48, 0xD8, 0x73,
260x95, 0xA4, 0xF7, 0x02, 0x06, 0x0A, 0x1E, 0x22, 0x66, 0xAA, 0xE5,
270x34, 0x5C, 0xE4, 0x37, 0x59, 0xEB, 0x26, 0x6A, 0xBE, 0xD9, 0x70,
280x90, 0xAB, 0xE6, 0x31, 0x53, 0xF5, 0x04, 0x0C, 0x14, 0x3C, 0x44,
290xCC, 0x4F, 0xD1, 0x68, 0xB8, 0xD3, 0x6E, 0xB2, 0xCD, 0x4C, 0xD4,
300x67, 0xA9, 0xE0, 0x3B, 0x4D, 0xD7, 0x62, 0xA6, 0xF1, 0x08, 0x18,
310x28, 0x78, 0x88, 0x83, 0x9E, 0xB9, 0xD0, 0x6B, 0xBD, 0xDC, 0x7F,
320x81, 0x98, 0xB3, 0xCE, 0x49, 0xDB, 0x76, 0x9A, 0xB5, 0xC4, 0x57,
330xF9, 0x10, 0x30, 0x50, 0xF0, 0x0B, 0x1D, 0x27, 0x69, 0xBB, 0xD6,
340x61, 0xA3, 0xFE, 0x19, 0x2B, 0x7D, 0x87, 0x92, 0xAD, 0xEC, 0x2F,
350x71, 0x93, 0xAE, 0xE9, 0x20, 0x60, 0xA0, 0xFB, 0x16, 0x3A, 0x4E,
360xD2, 0x6D, 0xB7, 0xC2, 0x5D, 0xE7, 0x32, 0x56, 0xFA, 0x15, 0x3F,
370x41, 0xC3, 0x5E, 0xE2, 0x3D, 0x47, 0xC9, 0x40, 0xC0, 0x5B, 0xED,
380x2C, 0x74, 0x9C, 0xBF, 0xDA, 0x75, 0x9F, 0xBA, 0xD5, 0x64, 0xAC,
390xEF, 0x2A, 0x7E, 0x82, 0x9D, 0xBC, 0xDF, 0x7A, 0x8E, 0x89, 0x80,
400x9B, 0xB6, 0xC1, 0x58, 0xE8, 0x23, 0x65, 0xAF, 0xEA, 0x25, 0x6F,
410xB1, 0xC8, 0x43, 0xC5, 0x54, 0xFC, 0x1F, 0x21, 0x63, 0xA5, 0xF4,
420x07, 0x09, 0x1B, 0x2D, 0x77, 0x99, 0xB0, 0xCB, 0x46, 0xCA, 0x45,
430xCF, 0x4A, 0xDE, 0x79, 0x8B, 0x86, 0x91, 0xA8, 0xE3, 0x3E, 0x42,
440xC6, 0x51, 0xF3, 0x0E, 0x12, 0x36, 0x5A, 0xEE, 0x29, 0x7B, 0x8D,
450x8C, 0x8F, 0x8A, 0x85, 0x94, 0xA7, 0xF2, 0x0D, 0x17, 0x39, 0x4B,
460xDD, 0x7C, 0x84, 0x97, 0xA2, 0xFD, 0x1C, 0x24, 0x6C, 0xB4, 0xC7,
52alignas(64)
const uint8_t RTSS_LOG[] = {
530x90, 0x00, 0x19, 0x01, 0x32, 0x02, 0x1A, 0xC6, 0x4B, 0xC7, 0x1B,
540x68, 0x33, 0xEE, 0xDF, 0x03, 0x64, 0x04, 0xE0, 0x0E, 0x34, 0x8D,
550x81, 0xEF, 0x4C, 0x71, 0x08, 0xC8, 0xF8, 0x69, 0x1C, 0xC1, 0x7D,
560xC2, 0x1D, 0xB5, 0xF9, 0xB9, 0x27, 0x6A, 0x4D, 0xE4, 0xA6, 0x72,
570x9A, 0xC9, 0x09, 0x78, 0x65, 0x2F, 0x8A, 0x05, 0x21, 0x0F, 0xE1,
580x24, 0x12, 0xF0, 0x82, 0x45, 0x35, 0x93, 0xDA, 0x8E, 0x96, 0x8F,
590xDB, 0xBD, 0x36, 0xD0, 0xCE, 0x94, 0x13, 0x5C, 0xD2, 0xF1, 0x40,
600x46, 0x83, 0x38, 0x66, 0xDD, 0xFD, 0x30, 0xBF, 0x06, 0x8B, 0x62,
610xB3, 0x25, 0xE2, 0x98, 0x22, 0x88, 0x91, 0x10, 0x7E, 0x6E, 0x48,
620xC3, 0xA3, 0xB6, 0x1E, 0x42, 0x3A, 0x6B, 0x28, 0x54, 0xFA, 0x85,
630x3D, 0xBA, 0x2B, 0x79, 0x0A, 0x15, 0x9B, 0x9F, 0x5E, 0xCA, 0x4E,
640xD4, 0xAC, 0xE5, 0xF3, 0x73, 0xA7, 0x57, 0xAF, 0x58, 0xA8, 0x50,
650xF4, 0xEA, 0xD6, 0x74, 0x4F, 0xAE, 0xE9, 0xD5, 0xE7, 0xE6, 0xAD,
660xE8, 0x2C, 0xD7, 0x75, 0x7A, 0xEB, 0x16, 0x0B, 0xF5, 0x59, 0xCB,
670x5F, 0xB0, 0x9C, 0xA9, 0x51, 0xA0, 0x7F, 0x0C, 0xF6, 0x6F, 0x17,
680xC4, 0x49, 0xEC, 0xD8, 0x43, 0x1F, 0x2D, 0xA4, 0x76, 0x7B, 0xB7,
690xCC, 0xBB, 0x3E, 0x5A, 0xFB, 0x60, 0xB1, 0x86, 0x3B, 0x52, 0xA1,
700x6C, 0xAA, 0x55, 0x29, 0x9D, 0x97, 0xB2, 0x87, 0x90, 0x61, 0xBE,
710xDC, 0xFC, 0xBC, 0x95, 0xCF, 0xCD, 0x37, 0x3F, 0x5B, 0xD1, 0x53,
720x39, 0x84, 0x3C, 0x41, 0xA2, 0x6D, 0x47, 0x14, 0x2A, 0x9E, 0x5D,
730x56, 0xF2, 0xD3, 0xAB, 0x44, 0x11, 0x92, 0xD9, 0x23, 0x20, 0x2E,
740x89, 0xB4, 0x7C, 0xB8, 0x26, 0x77, 0x99, 0xE3, 0xA5, 0x67, 0x4A,
750xED, 0xDE, 0xC5, 0x31, 0xFE, 0x18, 0x0D, 0x63, 0x8C, 0x80, 0xC0,
78uint8_t gfp_mul(uint8_t x, uint8_t
y)
82 return RTSS_EXP[(RTSS_LOG[x] + RTSS_LOG[
y]) % 255];
85uint8_t rtss_hash_id(std::string_view hash_name)
87 if(hash_name ==
"None")
89 else if(hash_name ==
"SHA-1")
91 else if(hash_name ==
"SHA-256")
94 throw Invalid_Argument(
"RTSS only supports SHA-1 and SHA-256");
97std::unique_ptr<HashFunction> get_rtss_hash_by_id(uint8_t
id)
100 return std::unique_ptr<HashFunction>();
106 throw Decoding_Error(
"Unknown RTSS hash identifier");
118 m_contents.assign(bin, bin + len);
126 if(m_contents.size() < RTSS_HEADER_SIZE + 1)
129 return m_contents[20];
134 return hex_encode(m_contents.data(), m_contents.size());
137std::vector<RTSS_Share>
139 const uint8_t S[], uint16_t S_len,
140 const uint8_t identifier[16],
144 std::vector<uint8_t>(identifier, identifier + 16),
149std::vector<RTSS_Share>
151 const uint8_t S[], uint16_t S_len,
152 const std::vector<uint8_t>& identifier,
153 std::string_view hash_fn,
156 if(M <= 1 || N <= 1 || M > N || N >= 255)
159 if(identifier.size() > 16)
162 const uint8_t hash_id = rtss_hash_id(hash_fn);
164 std::unique_ptr<HashFunction> hash;
171 secret += hash->process(S, S_len);
173 if(secret.size() >= 0xFFFE)
174 throw Encoding_Error(
"RTSS_Share::split secret too large for TSS format");
177 const uint16_t share_len =
static_cast<uint16_t
>(secret.size() + 1);
180 copy_mem(&share_header[0], identifier.data(), identifier.size());
181 share_header[16] = hash_id;
182 share_header[17] = M;
183 share_header[18] = get_byte<0>(share_len);
184 share_header[19] = get_byte<1>(share_len);
187 std::vector<RTSS_Share> shares(N);
189 for(uint8_t i = 0; i != N; ++i)
191 shares[i].m_contents.reserve(share_header.size() + share_len);
192 shares[i].m_contents = share_header;
196 for(uint8_t i = 0; i != N; ++i)
197 shares[i].m_contents.push_back(i+1);
199 for(
size_t i = 0; i != secret.size(); ++i)
201 std::vector<uint8_t> coefficients(M-1);
202 rng.
randomize(coefficients.data(), coefficients.size());
204 for(uint8_t j = 0; j != N; ++j)
206 const uint8_t
X = j + 1;
208 uint8_t sum = secret[i];
211 for(
size_t k = 0; k != coefficients.size(); ++k)
213 sum ^= gfp_mul(X_i, coefficients[k]);
214 X_i = gfp_mul(X_i,
X);
217 shares[j].m_contents.push_back(sum);
227 if(shares.size() <= 1)
228 throw Decoding_Error(
"Insufficient shares to do TSS reconstruction");
230 for(
size_t i = 0; i != shares.size(); ++i)
232 if(shares[i].
size() < RTSS_HEADER_SIZE + 1)
240 if(shares[i].
size() != shares[0].
size())
243 if(!
same_mem(&shares[0].m_contents[0],
244 &shares[i].m_contents[0], RTSS_HEADER_SIZE))
249 const uint8_t N = shares[0].m_contents[17];
251 if(shares.size() < N)
252 throw Decoding_Error(
"Insufficient shares to do TSS reconstruction");
254 const uint16_t share_len =
make_uint16(shares[0].m_contents[18],
255 shares[0].m_contents[19]);
257 const uint8_t hash_id = shares[0].m_contents[16];
258 auto hash = get_rtss_hash_by_id(hash_id);
259 const size_t hash_len = (hash ? hash->output_length() : 0);
261 if(shares[0].
size() != RTSS_HEADER_SIZE + share_len)
269 if(shares[0].
size() <= RTSS_HEADER_SIZE + 1 + hash_len)
273 std::vector<uint8_t> V(shares.size());
276 for(
size_t i = RTSS_HEADER_SIZE + 1; i != shares[0].size(); ++i)
278 for(
size_t j = 0; j != V.size(); ++j)
279 V[j] = shares[j].m_contents[i];
282 for(
size_t k = 0; k != shares.size(); ++k)
286 for(
size_t l = 0; l != shares.size(); ++l)
291 uint8_t share_k = shares[k].share_id();
292 uint8_t share_l = shares[l].share_id();
294 if(share_k == share_l)
297 uint8_t div = RTSS_EXP[(255 +
299 RTSS_LOG[share_k ^ share_l]) % 255];
301 r2 = gfp_mul(r2, div);
304 r ^= gfp_mul(V[k], r2);
306 recovered.push_back(r);
311 if(recovered.size() < hash->output_length())
312 throw Decoding_Error(
"RTSS recovered value too short to be valid");
314 const size_t secret_len = recovered.size() - hash->output_length();
316 hash->update(recovered.data(), secret_len);
320 &recovered[secret_len],
321 hash->output_length()))
327 recovered.resize(secret_len);
static std::unique_ptr< HashFunction > create_or_throw(std::string_view algo_spec, std::string_view provider="")
static std::vector< RTSS_Share > split(uint8_t M, uint8_t N, const uint8_t secret[], uint16_t secret_len, const uint8_t identifier[16], RandomNumberGenerator &rng)
std::string to_string() const
static secure_vector< uint8_t > reconstruct(const std::vector< RTSS_Share > &shares)
void randomize(std::span< uint8_t > output)
secure_vector< uint8_t > hex_decode_locked(const char input[], size_t input_length, bool ignore_ws)
constexpr void copy_mem(T *out, const T *in, size_t n)
bool constant_time_compare(const uint8_t x[], const uint8_t y[], size_t len)
void hex_encode(char output[], const uint8_t input[], size_t input_length, bool uppercase)
bool same_mem(const T *p1, const T *p2, size_t n)
std::vector< T, secure_allocator< T > > secure_vector
constexpr uint16_t make_uint16(uint8_t i0, uint8_t i1)