Line data    Source code

       1             : // Copyright (c) 2016-2020 The ZCash developers
       2             : // Copyright (c) 2020 The PIVX Core developers
       3             : // Distributed under the MIT software license, see the accompanying
       4             : // file COPYING or http://www.opensource.org/licenses/mit-license.php.
       5             : 
       6             : 
       7             : #include "prf.h"
       8             : #include "crypto/sha256.h"
       9             : #include "hash.h"
      10             : 
      11             : #include <array>
      12             : #include <sodium.h>
      13             : #include <librustzcash.h>
      14             : 
      15             : const unsigned char ZCASH_EXPANDSEED_PERSONALIZATION[crypto_generichash_blake2b_PERSONALBYTES] = {'Z','c','a','s','h','_','E','x','p','a','n','d','S','e','e','d'};
      16             : 
      17             : // Sapling
      18         427 : std::array<unsigned char, 64> PRF_expand(const uint256& sk, unsigned char t)
      19             : {
      20         427 :     std::array<unsigned char, 64> res;
      21         427 :     unsigned char blob[33];
      22             : 
      23         427 :     memcpy(&blob[0], sk.begin(), 32);
      24         427 :     blob[32] = t;
      25             : 
      26         427 :     crypto_generichash_blake2b_state state;
      27         427 :     crypto_generichash_blake2b_init_salt_personal(&state, nullptr, 0, 64, nullptr, ZCASH_EXPANDSEED_PERSONALIZATION);
      28         427 :     crypto_generichash_blake2b_update(&state, blob, 33);
      29         427 :     crypto_generichash_blake2b_final(&state, res.data(), 64);
      30             : 
      31         427 :     return res;
      32             : }
      33             : 
      34          62 : uint256 PRF_ask(const uint256& sk)
      35             : {
      36          62 :     uint256 ask;
      37          62 :     auto tmp = PRF_expand(sk, 0);
      38          62 :     librustzcash_to_scalar(tmp.data(), ask.begin());
      39          62 :     return ask;
      40             : }
      41             : 
      42          62 : uint256 PRF_nsk(const uint256& sk)
      43             : {
      44          62 :     uint256 nsk;
      45          62 :     auto tmp = PRF_expand(sk, 1);
      46          62 :     librustzcash_to_scalar(tmp.data(), nsk.begin());
      47          62 :     return nsk;
      48             : }
      49             : 
      50         303 : uint256 PRF_ovk(const uint256& sk)
      51             : {
      52         303 :     uint256 ovk;
      53         303 :     auto tmp = PRF_expand(sk, 2);
      54         303 :     memcpy(ovk.begin(), tmp.data(), 32);
      55         303 :     return ovk;
      56             : }
      57             : 
      58          18 : std::array<unsigned char, 11> default_diversifier(const uint256& sk)
      59             : {
      60          18 :     std::array<unsigned char, 11> res;
      61          18 :     unsigned char blob[34];
      62             : 
      63          18 :     memcpy(&blob[0], sk.begin(), 32);
      64          18 :     blob[32] = 3;
      65             : 
      66          18 :     blob[33] = 0;
      67          48 :     while (true) {
      68          33 :         crypto_generichash_blake2b_state state;
      69          33 :         crypto_generichash_blake2b_init_salt_personal(&state, nullptr, 0, 64, nullptr, ZCASH_EXPANDSEED_PERSONALIZATION);
      70          33 :         crypto_generichash_blake2b_update(&state, blob, 34);
      71          33 :         crypto_generichash_blake2b_final(&state, res.data(), 11);
      72             : 
      73          33 :         if (librustzcash_check_diversifier(res.data())) {
      74             :             break;
      75          15 :         } else if (blob[33] == 255) {
      76           0 :             throw std::runtime_error("librustzcash_check_diversifier did not return valid diversifier");
      77             :         }
      78          15 :         blob[33] += 1;
      79          15 :     }
      80             : 
      81          18 :     return res;
      82             : }