108 lines
3.9 KiB
C++
108 lines
3.9 KiB
C++
//
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// Copyright Aliaksei Levin (levlam@telegram.org), Arseny Smirnov (arseny30@gmail.com) 2014-2022
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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#include "td/mtproto/KDF.h"
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#include "td/utils/as.h"
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#include "td/utils/common.h"
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#include "td/utils/crypto.h"
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#include "td/utils/logging.h"
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namespace td {
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namespace mtproto {
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void KDF(Slice auth_key, const UInt128 &msg_key, int X, UInt256 *aes_key, UInt256 *aes_iv) {
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LOG_CHECK(auth_key.size() == 2048 / 8) << auth_key.size();
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const char *auth_key_raw = auth_key.data();
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uint8 buf[48];
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as<UInt128>(buf) = msg_key;
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as<UInt256>(buf + 16) = as<UInt256>(auth_key_raw + X);
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uint8 sha1_a[20];
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sha1(Slice(buf, 48), sha1_a);
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as<UInt128>(buf) = as<UInt128>(auth_key_raw + X + 32);
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as<UInt128>(buf + 16) = msg_key;
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as<UInt128>(buf + 32) = as<UInt128>(auth_key_raw + X + 48);
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uint8 sha1_b[20];
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sha1(Slice(buf, 48), sha1_b);
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as<UInt256>(buf) = as<UInt256>(auth_key_raw + 64 + X);
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as<UInt128>(buf + 32) = msg_key;
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uint8 sha1_c[20];
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sha1(Slice(buf, 48), sha1_c);
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as<UInt128>(buf) = msg_key;
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as<UInt256>(buf + 16) = as<UInt256>(auth_key_raw + 96 + X);
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uint8 sha1_d[20];
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sha1(Slice(buf, 48), sha1_d);
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as<uint64>(aes_key->raw) = as<uint64>(sha1_a);
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as<UInt<96>>(aes_key->raw + 8) = as<UInt<96>>(sha1_b + 8);
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as<UInt<96>>(aes_key->raw + 20) = as<UInt<96>>(sha1_c + 4);
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as<UInt<96>>(aes_iv->raw) = as<UInt<96>>(sha1_a + 8);
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as<uint64>(aes_iv->raw + 12) = as<uint64>(sha1_b);
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as<uint32>(aes_iv->raw + 20) = as<uint32>(sha1_c + 16);
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as<uint64>(aes_iv->raw + 24) = as<uint64>(sha1_d);
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}
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void tmp_KDF(const UInt128 &server_nonce, const UInt256 &new_nonce, UInt256 *tmp_aes_key, UInt256 *tmp_aes_iv) {
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// tmp_aes_key := SHA1(new_nonce + server_nonce) + substr(SHA1(server_nonce + new_nonce), 0, 12);
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uint8 buf[512 / 8];
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as<UInt256>(buf) = new_nonce;
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as<UInt128>(buf + 32) = server_nonce;
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sha1(Slice(buf, 48), tmp_aes_key->raw);
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as<UInt128>(buf) = server_nonce;
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as<UInt256>(buf + 16) = new_nonce;
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uint8 sha1_server_new[20];
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sha1(Slice(buf, 48), sha1_server_new);
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as<UInt<96>>(tmp_aes_key->raw + 20) = as<UInt<96>>(sha1_server_new);
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// tmp_aes_iv := substr(SHA1(server_nonce + new_nonce), 12, 8) + SHA1(new_nonce + new_nonce) + substr(new_nonce, 0, 4)
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as<uint64>(tmp_aes_iv->raw) = as<uint64>(sha1_server_new + 12);
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as<UInt256>(buf) = new_nonce;
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as<UInt256>(buf + 32) = new_nonce;
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sha1(Slice(buf, 64), tmp_aes_iv->raw + 8);
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as<uint32>(tmp_aes_iv->raw + 28) = as<uint32>(new_nonce.raw);
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}
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void KDF2(Slice auth_key, const UInt128 &msg_key, int X, UInt256 *aes_key, UInt256 *aes_iv) {
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uint8 buf_raw[36 + 16];
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MutableSlice buf(buf_raw, 36 + 16);
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Slice msg_key_slice = as_slice(msg_key);
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// sha256_a = SHA256 (msg_key + substr(auth_key, x, 36));
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buf.copy_from(msg_key_slice);
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buf.substr(16, 36).copy_from(auth_key.substr(X, 36));
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uint8 sha256_a_raw[32];
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MutableSlice sha256_a(sha256_a_raw, 32);
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sha256(buf, sha256_a);
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// sha256_b = SHA256 (substr(auth_key, 40+x, 36) + msg_key);
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buf.copy_from(auth_key.substr(40 + X, 36));
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buf.substr(36).copy_from(msg_key_slice);
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uint8 sha256_b_raw[32];
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MutableSlice sha256_b(sha256_b_raw, 32);
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sha256(buf, sha256_b);
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// aes_key = substr(sha256_a, 0, 8) + substr(sha256_b, 8, 16) + substr(sha256_a, 24, 8);
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MutableSlice aes_key_slice(aes_key->raw, sizeof(aes_key->raw));
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aes_key_slice.copy_from(sha256_a.substr(0, 8));
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aes_key_slice.substr(8).copy_from(sha256_b.substr(8, 16));
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aes_key_slice.substr(24).copy_from(sha256_a.substr(24, 8));
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// aes_iv = substr(sha256_b, 0, 8) + substr(sha256_a, 8, 16) + substr(sha256_b, 24, 8);
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MutableSlice aes_iv_slice(aes_iv->raw, sizeof(aes_iv->raw));
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aes_iv_slice.copy_from(sha256_b.substr(0, 8));
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aes_iv_slice.substr(8).copy_from(sha256_a.substr(8, 16));
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aes_iv_slice.substr(24).copy_from(sha256_b.substr(24, 8));
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}
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} // namespace mtproto
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} // namespace td
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