Coverage Report

Created: 2020-11-21 08:34

/src/botan/src/lib/pubkey/ed25519/ed25519.cpp
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Source (jump to first uncovered line)
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/*
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* Ed25519
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* (C) 2017 Ribose Inc
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*
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* Based on the public domain code from SUPERCOP ref10 by
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* Peter Schwabe, Daniel J. Bernstein, Niels Duif, Tanja Lange, Bo-Yin Yang
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*
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* Botan is released under the Simplified BSD License (see license.txt)
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*/
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#include <botan/ed25519.h>
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#include <botan/internal/ed25519_internal.h>
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#include <botan/internal/sha2_64.h>
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#include <botan/rng.h>
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namespace Botan {
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void ed25519_gen_keypair(uint8_t* pk, uint8_t* sk, const uint8_t seed[32])
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   {
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   uint8_t az[64];
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   SHA_512 sha;
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   sha.update(seed, 32);
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   sha.final(az);
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   az[0] &= 248;
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   az[31] &= 63;
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   az[31] |= 64;
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   ge_scalarmult_base(pk, az);
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   // todo copy_mem
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   copy_mem(sk, seed, 32);
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   copy_mem(sk + 32, pk, 32);
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   }
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void ed25519_sign(uint8_t sig[64],
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                  const uint8_t m[], size_t mlen,
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                  const uint8_t sk[64],
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                  const uint8_t domain_sep[], size_t domain_sep_len)
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   {
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   uint8_t az[64];
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   uint8_t nonce[64];
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   uint8_t hram[64];
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   SHA_512 sha;
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   sha.update(sk, 32);
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   sha.final(az);
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   az[0] &= 248;
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   az[31] &= 63;
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   az[31] |= 64;
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   sha.update(domain_sep, domain_sep_len);
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   sha.update(az + 32, 32);
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   sha.update(m, mlen);
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   sha.final(nonce);
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   sc_reduce(nonce);
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   ge_scalarmult_base(sig, nonce);
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   sha.update(domain_sep, domain_sep_len);
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   sha.update(sig, 32);
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   sha.update(sk + 32, 32);
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   sha.update(m, mlen);
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   sha.final(hram);
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   sc_reduce(hram);
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   sc_muladd(sig + 32, hram, az, nonce);
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   }
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bool ed25519_verify(const uint8_t* m, size_t mlen,
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                    const uint8_t sig[64],
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                    const uint8_t* pk,
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                    const uint8_t domain_sep[], size_t domain_sep_len)
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   {
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   uint8_t h[64];
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   uint8_t rcheck[32];
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   ge_p3 A;
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   SHA_512 sha;
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   if(sig[63] & 224)
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      {
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      return false;
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      }
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   if(ge_frombytes_negate_vartime(&A, pk) != 0)
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      {
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      return false;
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      }
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   sha.update(domain_sep, domain_sep_len);
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   sha.update(sig, 32);
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   sha.update(pk, 32);
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   sha.update(m, mlen);
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   sha.final(h);
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   sc_reduce(h);
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   ge_double_scalarmult_vartime(rcheck, h, &A, sig + 32);
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   return constant_time_compare(rcheck, sig, 32);
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   }
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}