mirror of
https://github.com/oxen-io/lokinet.git
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7caa87862e
All #ifndef guards on headers have been removed, I think, in favor of #pragma once Headers are now included as `#include "filename"` if the included file resides in the same directory as the file including it, or any subdirectory therein. Otherwise they are included as `#include <project/top/dir/relative/path/filename>` The above does not include system/os headers.
495 lines
14 KiB
C++
495 lines
14 KiB
C++
#include "crypto_libsodium.hpp"
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#include <sodium/crypto_generichash.h>
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#include <sodium/crypto_sign.h>
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#include <sodium/crypto_scalarmult.h>
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#include <sodium/crypto_scalarmult_ed25519.h>
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#include <sodium/crypto_stream_xchacha20.h>
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#include <sodium/crypto_core_ed25519.h>
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#include <sodium/crypto_aead_xchacha20poly1305.h>
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#include <sodium/randombytes.h>
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#include <sodium/utils.h>
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#include <llarp/util/mem.hpp>
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#include <llarp/util/endian.hpp>
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#include <llarp/util/str.hpp>
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#include <cassert>
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#include <cstring>
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extern "C"
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{
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extern int
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sodium_init(void);
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}
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namespace llarp
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{
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namespace sodium
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{
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static bool
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dh(llarp::SharedSecret& out,
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const PubKey& client_pk,
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const PubKey& server_pk,
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const uint8_t* themPub,
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const SecretKey& usSec)
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{
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llarp::SharedSecret shared;
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crypto_generichash_state h;
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if (crypto_scalarmult_curve25519(shared.data(), usSec.data(), themPub))
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{
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return false;
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}
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crypto_generichash_blake2b_init(&h, nullptr, 0U, shared.size());
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crypto_generichash_blake2b_update(&h, client_pk.data(), 32);
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crypto_generichash_blake2b_update(&h, server_pk.data(), 32);
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crypto_generichash_blake2b_update(&h, shared.data(), 32);
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crypto_generichash_blake2b_final(&h, out.data(), shared.size());
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return true;
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}
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static bool
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dh_client_priv(
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llarp::SharedSecret& shared, const PubKey& pk, const SecretKey& sk, const TunnelNonce& n)
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{
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llarp::SharedSecret dh_result;
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if (dh(dh_result, sk.toPublic(), pk, pk.data(), sk))
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{
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return crypto_generichash_blake2b(shared.data(), 32, n.data(), 32, dh_result.data(), 32)
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!= -1;
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}
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llarp::LogWarn("crypto::dh_client - dh failed");
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return false;
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}
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static bool
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dh_server_priv(
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llarp::SharedSecret& shared, const PubKey& pk, const SecretKey& sk, const TunnelNonce& n)
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{
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llarp::SharedSecret dh_result;
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if (dh(dh_result, pk, sk.toPublic(), pk.data(), sk))
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{
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return crypto_generichash_blake2b(shared.data(), 32, n.data(), 32, dh_result.data(), 32)
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!= -1;
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}
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llarp::LogWarn("crypto::dh_server - dh failed");
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return false;
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}
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CryptoLibSodium::CryptoLibSodium()
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{
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if (sodium_init() == -1)
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{
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throw std::runtime_error("sodium_init() returned -1");
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}
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char* avx2 = std::getenv("AVX2_FORCE_DISABLE");
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if (avx2 && std::string(avx2) == "1")
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{
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ntru_init(1);
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}
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else
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{
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ntru_init(0);
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}
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int seed = 0;
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randombytes(reinterpret_cast<unsigned char*>(&seed), sizeof(seed));
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srand(seed);
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}
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std::optional<AlignedBuffer<32>>
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CryptoLibSodium::maybe_decrypt_name(
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std::string_view ciphertext, SymmNonce nounce, std::string_view name)
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{
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const auto payloadsize = ciphertext.size() - crypto_aead_xchacha20poly1305_ietf_ABYTES;
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if (payloadsize != 32)
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return {};
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SharedSecret derivedKey{};
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ShortHash namehash{};
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const llarp_buffer_t namebuf(reinterpret_cast<const char*>(name.data()), name.size());
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if (not shorthash(namehash, namebuf))
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return {};
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if (not hmac(derivedKey.data(), namebuf, namehash))
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return {};
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AlignedBuffer<32> result{};
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if (crypto_aead_xchacha20poly1305_ietf_decrypt(
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result.data(),
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nullptr,
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nullptr,
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reinterpret_cast<const byte_t*>(ciphertext.data()),
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ciphertext.size(),
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nullptr,
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0,
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nounce.data(),
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derivedKey.data())
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== -1)
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{
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return {};
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}
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return result;
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}
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bool
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CryptoLibSodium::xchacha20(
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const llarp_buffer_t& buff, const SharedSecret& k, const TunnelNonce& n)
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{
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return crypto_stream_xchacha20_xor(buff.base, buff.base, buff.sz, n.data(), k.data()) == 0;
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}
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bool
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CryptoLibSodium::xchacha20_alt(
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const llarp_buffer_t& out, const llarp_buffer_t& in, const SharedSecret& k, const byte_t* n)
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{
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if (in.sz > out.sz)
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return false;
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return crypto_stream_xchacha20_xor(out.base, in.base, in.sz, n, k.data()) == 0;
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}
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bool
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CryptoLibSodium::dh_client(
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llarp::SharedSecret& shared, const PubKey& pk, const SecretKey& sk, const TunnelNonce& n)
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{
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return dh_client_priv(shared, pk, sk, n);
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}
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/// path dh relay side
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bool
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CryptoLibSodium::dh_server(
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llarp::SharedSecret& shared, const PubKey& pk, const SecretKey& sk, const TunnelNonce& n)
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{
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return dh_server_priv(shared, pk, sk, n);
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}
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/// transport dh client side
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bool
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CryptoLibSodium::transport_dh_client(
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llarp::SharedSecret& shared, const PubKey& pk, const SecretKey& sk, const TunnelNonce& n)
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{
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return dh_client_priv(shared, pk, sk, n);
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}
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/// transport dh server side
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bool
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CryptoLibSodium::transport_dh_server(
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llarp::SharedSecret& shared, const PubKey& pk, const SecretKey& sk, const TunnelNonce& n)
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{
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return dh_server_priv(shared, pk, sk, n);
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}
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bool
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CryptoLibSodium::shorthash(ShortHash& result, const llarp_buffer_t& buff)
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{
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return crypto_generichash_blake2b(
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result.data(), ShortHash::SIZE, buff.base, buff.sz, nullptr, 0)
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!= -1;
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}
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bool
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CryptoLibSodium::hmac(byte_t* result, const llarp_buffer_t& buff, const SharedSecret& secret)
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{
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return crypto_generichash_blake2b(
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result, HMACSIZE, buff.base, buff.sz, secret.data(), HMACSECSIZE)
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!= -1;
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}
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static bool
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hash(uint8_t* result, const llarp_buffer_t& buff)
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{
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return crypto_generichash_blake2b(result, HASHSIZE, buff.base, buff.sz, nullptr, 0) != -1;
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}
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bool
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CryptoLibSodium::sign(Signature& sig, const SecretKey& secret, const llarp_buffer_t& buf)
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{
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return crypto_sign_detached(sig.data(), nullptr, buf.base, buf.sz, secret.data()) != -1;
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}
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bool
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CryptoLibSodium::sign(Signature& sig, const PrivateKey& privkey, const llarp_buffer_t& buf)
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{
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PubKey pubkey;
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privkey.toPublic(pubkey);
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crypto_hash_sha512_state hs;
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unsigned char nonce[64];
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unsigned char hram[64];
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unsigned char mulres[32];
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// r = H(s || M) where here s is pseudorandom bytes typically generated as
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// part of hashing the seed (i.e. [a,s] = H(k)), but for derived
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// PrivateKeys will come from a hash of the root key's s concatenated with
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// the derivation hash.
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crypto_hash_sha512_init(&hs);
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crypto_hash_sha512_update(&hs, privkey.signingHash(), 32);
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crypto_hash_sha512_update(&hs, buf.base, buf.sz);
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crypto_hash_sha512_final(&hs, nonce);
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crypto_core_ed25519_scalar_reduce(nonce, nonce);
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// copy pubkey into sig to make (for now) sig = (R || A)
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memmove(sig.data() + 32, pubkey.data(), 32);
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// R = r * B
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crypto_scalarmult_ed25519_base_noclamp(sig.data(), nonce);
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// hram = H(R || A || M)
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crypto_hash_sha512_init(&hs);
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crypto_hash_sha512_update(&hs, sig.data(), 64);
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crypto_hash_sha512_update(&hs, buf.base, buf.sz);
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crypto_hash_sha512_final(&hs, hram);
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// S = r + H(R || A || M) * s, so sig = (R || S)
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crypto_core_ed25519_scalar_reduce(hram, hram);
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crypto_core_ed25519_scalar_mul(mulres, hram, privkey.data());
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crypto_core_ed25519_scalar_add(sig.data() + 32, mulres, nonce);
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sodium_memzero(nonce, sizeof nonce);
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return true;
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}
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bool
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CryptoLibSodium::verify(const PubKey& pub, const llarp_buffer_t& buf, const Signature& sig)
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{
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return crypto_sign_verify_detached(sig.data(), buf.base, buf.sz, pub.data()) != -1;
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}
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/// clamp a 32 byte ec point
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static void
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clamp_ed25519(byte_t* out)
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{
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out[0] &= 248;
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out[31] &= 127;
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out[31] |= 64;
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}
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template <typename K>
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static K
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clamp(const K& p)
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{
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K out = p;
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clamp_ed25519(out);
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return out;
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}
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template <typename K>
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static bool
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is_clamped(const K& key)
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{
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K other(key);
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clamp_ed25519(other.data());
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return other == key;
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}
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constexpr static char derived_key_hash_str[161] =
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"just imagine what would happen if we all decided to understand. you "
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"can't in the and by be or then before so just face it this text hurts "
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"to read? lokinet yolo!";
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template <typename K>
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static bool
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make_scalar(AlignedBuffer<32>& out, const K& k, uint64_t i)
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{
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// b = BLIND-STRING || k || i
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std::array<byte_t, 160 + K::SIZE + sizeof(uint64_t)> buf;
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std::copy(derived_key_hash_str, derived_key_hash_str + 160, buf.begin());
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std::copy(k.begin(), k.end(), buf.begin() + 160);
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htole64buf(buf.data() + 160 + K::SIZE, i);
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// n = H(b)
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// h = make_point(n)
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ShortHash n;
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return -1
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!= crypto_generichash_blake2b(
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n.data(), ShortHash::SIZE, buf.data(), buf.size(), nullptr, 0)
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&& -1 != crypto_core_ed25519_from_uniform(out.data(), n.data());
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}
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static AlignedBuffer<32> zero;
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bool
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CryptoLibSodium::derive_subkey(
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PubKey& out_pubkey,
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const PubKey& root_pubkey,
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uint64_t key_n,
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const AlignedBuffer<32>* hash)
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{
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// scalar h = H( BLIND-STRING || root_pubkey || key_n )
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AlignedBuffer<32> h;
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if (hash)
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h = *hash;
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else if (not make_scalar(h, root_pubkey, key_n))
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{
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LogError("cannot make scalar");
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return false;
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}
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return 0 == crypto_scalarmult_ed25519(out_pubkey.data(), h.data(), root_pubkey.data());
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}
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bool
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CryptoLibSodium::derive_subkey_private(
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PrivateKey& out_key,
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const SecretKey& root_key,
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uint64_t key_n,
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const AlignedBuffer<32>* hash)
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{
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// Derives a private subkey from a root key.
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//
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// The basic idea is:
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//
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// h = H( BLIND-STRING || A || key_n )
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// a - private key
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// A = aB - public key
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// s - signing hash
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// a' = ah - derived private key
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// A' = a'B = (ah)B - derived public key
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// s' = H(h || s) - derived signing hash
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//
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// libsodium throws some wrenches in the mechanics which are a nuisance,
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// the biggest of which is that sodium's secret key is *not* `a`; rather
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// it is the seed. If you want to get the private key (i.e. "a"), you
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// need to SHA-512 hash it and then clamp that.
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//
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// This also makes signature verification harder: we can't just use
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// sodium's sign function because it wants to be given the seed rather
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// than the private key, and moreover we can't actually *get* the seed to
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// make libsodium happy because we only have `ah` above; thus we
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// reimplemented most of sodium's detached signing function but without
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// the hash step.
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//
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// Lastly, for the signing hash s', we need some value that is both
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// different from the root s but also unknowable from the public key
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// (since otherwise `r` in the signing function would be known), so we
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// generate it from a hash of `h` and the root key's (psuedorandom)
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// signing hash, `s`.
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//
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const auto root_pubkey = root_key.toPublic();
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AlignedBuffer<32> h;
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if (hash)
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h = *hash;
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else if (not make_scalar(h, root_pubkey, key_n))
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{
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LogError("cannot make scalar");
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return false;
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}
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h[0] &= 248;
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h[31] &= 63;
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h[31] |= 64;
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PrivateKey a;
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if (!root_key.toPrivate(a))
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return false;
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// a' = ha
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crypto_core_ed25519_scalar_mul(out_key.data(), h.data(), a.data());
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// s' = H(h || s)
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std::array<byte_t, 64> buf;
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std::copy(h.begin(), h.end(), buf.begin());
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std::copy(a.signingHash(), a.signingHash() + 32, buf.begin() + 32);
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return -1
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!= crypto_generichash_blake2b(
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out_key.signingHash(), 32, buf.data(), buf.size(), nullptr, 0);
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return true;
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}
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bool
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CryptoLibSodium::seed_to_secretkey(llarp::SecretKey& secret, const llarp::IdentitySecret& seed)
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{
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return crypto_sign_ed25519_seed_keypair(secret.data() + 32, secret.data(), seed.data()) != -1;
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}
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void
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CryptoLibSodium::randomize(const llarp_buffer_t& buff)
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{
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randombytes((unsigned char*)buff.base, buff.sz);
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}
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void
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CryptoLibSodium::randbytes(byte_t* ptr, size_t sz)
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{
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randombytes((unsigned char*)ptr, sz);
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}
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void
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CryptoLibSodium::identity_keygen(llarp::SecretKey& keys)
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{
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PubKey pk;
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int result = crypto_sign_keypair(pk.data(), keys.data());
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assert(result != -1);
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const PubKey sk_pk = keys.toPublic();
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assert(pk == sk_pk);
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(void)result;
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(void)sk_pk;
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// encryption_keygen(keys);
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}
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bool
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CryptoLibSodium::check_identity_privkey(const llarp::SecretKey& keys)
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{
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AlignedBuffer<crypto_sign_SEEDBYTES> seed;
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llarp::PubKey pk;
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llarp::SecretKey sk;
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if (crypto_sign_ed25519_sk_to_seed(seed.data(), keys.data()) == -1)
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return false;
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if (crypto_sign_seed_keypair(pk.data(), sk.data(), seed.data()) == -1)
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return false;
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return keys.toPublic() == pk && sk == keys;
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}
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void
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CryptoLibSodium::encryption_keygen(llarp::SecretKey& keys)
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{
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auto d = keys.data();
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randbytes(d, 32);
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crypto_scalarmult_curve25519_base(d + 32, d);
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}
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bool
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CryptoLibSodium::pqe_encrypt(
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PQCipherBlock& ciphertext, SharedSecret& sharedkey, const PQPubKey& pubkey)
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{
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return crypto_kem_enc(ciphertext.data(), sharedkey.data(), pubkey.data()) != -1;
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}
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bool
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CryptoLibSodium::pqe_decrypt(
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const PQCipherBlock& ciphertext, SharedSecret& sharedkey, const byte_t* secretkey)
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{
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return crypto_kem_dec(sharedkey.data(), ciphertext.data(), secretkey) != -1;
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}
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void
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CryptoLibSodium::pqe_keygen(PQKeyPair& keypair)
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{
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auto d = keypair.data();
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crypto_kem_keypair(d + PQ_SECRETKEYSIZE, d);
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}
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} // namespace sodium
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const byte_t*
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seckey_topublic(const SecretKey& sec)
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{
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return sec.data() + 32;
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}
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const byte_t*
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pq_keypair_to_public(const PQKeyPair& k)
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{
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return k.data() + PQ_SECRETKEYSIZE;
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}
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const byte_t*
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pq_keypair_to_secret(const PQKeyPair& k)
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{
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return k.data();
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}
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uint64_t
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randint()
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{
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uint64_t i;
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randombytes((byte_t*)&i, sizeof(i));
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return i;
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}
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} // namespace llarp
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