60 lines
1.8 KiB
C++
60 lines
1.8 KiB
C++
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#include <algorithm>
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#include <cassert>
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#include <cstring>
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#include "aes.h"
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namespace AES {
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// ReSharper disable CppCStyleCast
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bool AES_init_ctx_iv(AES_ctx* ctx, const uint8_t* key, const uint8_t* iv) {
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memset(ctx, 0, sizeof(AES_ctx));
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if (BCryptOpenAlgorithmProvider(&ctx->hAlg, BCRYPT_AES_ALGORITHM, nullptr, 0) != 0) {
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return false;
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}
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if (BCryptSetProperty(ctx->hAlg, BCRYPT_CHAINING_MODE, (PUCHAR)BCRYPT_CHAIN_MODE_CBC, sizeof(BCRYPT_CHAIN_MODE_CBC),
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0) != 0) {
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BCryptCloseAlgorithmProvider(ctx->hAlg, 0);
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return false;
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}
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if (BCryptGenerateSymmetricKey(ctx->hAlg, &ctx->hKey, nullptr, 0, (PUCHAR)key, 0x10, 0) != 0) {
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BCryptCloseAlgorithmProvider(ctx->hAlg, 0);
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return false;
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}
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std::copy_n(iv, 0x10, ctx->iv);
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return true;
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}
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// buffer size MUST be mutile of AES_BLOCKLEN;
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// Suggest https://en.wikipedia.org/wiki/Padding_(cryptography)#PKCS7 for padding scheme
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// NOTES: you need to set IV in ctx via AES_init_ctx_iv() or AES_ctx_set_iv()
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// no IV should ever be reused with the same key
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size_t AES_CBC_encrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length) {
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// not implemented
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return 0;
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}
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size_t AES_CBC_decrypt_buffer(struct AES_ctx* ctx, uint8_t* buf, size_t length) {
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ULONG cbData{0};
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const auto len = static_cast<ULONG>(length);
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if (BCryptDecrypt(ctx->hKey, buf, len, nullptr, ctx->iv, sizeof(ctx->iv), buf, len, &cbData, 0) != 0) {
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assert(false && "BCryptDecrypt failed");
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return 0;
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}
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assert(cbData == len && "AES_CBC_decrypt_buffer: cbData != length");
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return cbData;
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}
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bool AES_cleanup(AES_ctx* ctx) {
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BCryptDestroyKey(ctx->hKey);
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BCryptCloseAlgorithmProvider(ctx->hAlg, 0);
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memset(ctx, 0, sizeof(AES_ctx));
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return true;
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}
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} // namespace AES
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