Repo created

TMessagesProj/jni/voip/tgcalls/CryptoHelper.cpp

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+#include "CryptoHelper.h"
+
+#include <cstring>
+#include <limits.h>
+
+namespace tgcalls {
+
+AesKeyIv PrepareAesKeyIv(const uint8_t *key, const uint8_t *msgKey, int x) {
+	auto result = AesKeyIv();
+
+	const auto sha256a = ConcatSHA256(
+		MemorySpan{ msgKey, 16 },
+		MemorySpan{ key + x, 36 });
+	const auto sha256b = ConcatSHA256(
+		MemorySpan{ key + 40 + x, 36 },
+		MemorySpan{ msgKey, 16 });
+	const auto aesKey = result.key.data();
+	const auto aesIv = result.iv.data();
+	memcpy(aesKey, sha256a.data(), 8);
+	memcpy(aesKey + 8, sha256b.data() + 8, 16);
+	memcpy(aesKey + 8 + 16, sha256a.data() + 24, 8);
+	memcpy(aesIv, sha256b.data(), 4);
+	memcpy(aesIv + 4, sha256a.data() + 8, 8);
+	memcpy(aesIv + 4 + 8, sha256b.data() + 24, 4);
+
+	return result;
+}
+
+void AesProcessCtr(MemorySpan from, void *to, AesKeyIv &&aesKeyIv) {
+	auto aes = AES_KEY();
+	AES_set_encrypt_key(
+		reinterpret_cast<const unsigned char*>(aesKeyIv.key.data()),
+		aesKeyIv.key.size() * CHAR_BIT,
+		&aes);
+
+	unsigned char ecountBuf[16] = { 0 };
+	unsigned int offsetInBlock = 0;
+
+#ifdef OPENSSL_IS_BORINGSSL
+	AES_ctr128_encrypt(
+			reinterpret_cast<const unsigned char*>(from.data),
+			reinterpret_cast<unsigned char*>(to),
+			from.size,
+			&aes,
+			reinterpret_cast<unsigned char*>(aesKeyIv.iv.data()),
+			ecountBuf,
+			&offsetInBlock);
+#else
+	CRYPTO_ctr128_encrypt(
+		reinterpret_cast<const unsigned char*>(from.data),
+		reinterpret_cast<unsigned char*>(to),
+		from.size,
+		&aes,
+		reinterpret_cast<unsigned char*>(aesKeyIv.iv.data()),
+		ecountBuf,
+		&offsetInBlock,
+		block128_f(AES_encrypt));
+#endif
+}
+
+} // namespace tgcalls