From aba862f45cbde3debe99e31bc8ec3e338c5bbf4a Mon Sep 17 00:00:00 2001
From: Per Larsson <p3rl@protonmail.com>
Date: Mon, 7 Feb 2022 13:00:29 +0100
Subject: Replaced crypto transform abstraction with a concrete API.

---
 zencore/include/zencore/crypto.h | 67 ++++++++++++++++++++++++++++++----------
 1 file changed, 50 insertions(+), 17 deletions(-)

(limited to 'zencore/include')

diff --git a/zencore/include/zencore/crypto.h b/zencore/include/zencore/crypto.h
index 44783cdeb..83d416b0f 100644
--- a/zencore/include/zencore/crypto.h
+++ b/zencore/include/zencore/crypto.h
@@ -7,36 +7,69 @@
 #include <zencore/zencore.h>
 
 #include <memory>
+#include <optional>
 
 namespace zen {
 
-/**
- * Experimental interface for a symmetric encryption/decryption algorithm.
- * Currenlty only AES 256 bit CBC is supported using OpenSSL.
- */
-class SymmetricCipher
+template<size_t BitCount>
+struct CryptoBits
 {
 public:
-	virtual ~SymmetricCipher() = default;
+	static constexpr size_t ByteCount = BitCount / 8;
 
-	virtual bool Initialize(MemoryView Key, MemoryView InitVector) = 0;
+	CryptoBits() = default;
 
-	struct CipherSettings
+	bool IsNull() const { return memcmp(&m_Bits, &Zero, ByteCount) == 0; }
+	bool IsValid() const { return IsNull() == false; }
+
+	size_t GetSize() const { return ByteCount; }
+	size_t GetBitCount() const { return BitCount; }
+
+	MemoryView GetView() const { return MemoryView(m_Bits, ByteCount); }
+
+	static CryptoBits FromMemoryView(MemoryView Bits)
 	{
-		size_t KeySize		  = 0;
-		size_t InitVectorSize = 0;
-		size_t BlockSize	  = 0;
-	};
+		if (Bits.GetSize() != ByteCount)
+		{
+			return CryptoBits();
+		}
 
-	virtual CipherSettings Settings() = 0;
+		return CryptoBits(Bits);
+	}
+
+	static CryptoBits FromString(std::string_view Str) { return FromMemoryView(MakeMemoryView(Str)); }
+
+private:
+	CryptoBits(MemoryView Bits)
+	{
+		ZEN_ASSERT(Bits.GetSize() == GetSize());
+		memcpy(&m_Bits, Bits.GetData(), GetSize());
+	}
 
-	virtual MemoryView Encrypt(MemoryView Data, MutableMemoryView EncryptionBuffer) = 0;
+	static constexpr uint8_t Zero[ByteCount] = {0};
 
-	virtual MemoryView Decrypt(MemoryView Data, MutableMemoryView DecryptionBuffer) = 0;
+	uint8_t m_Bits[ByteCount] = {0};
+};
+
+using AesKey256Bit = CryptoBits<256>;
+using AesIV128Bit  = CryptoBits<128>;
+
+class Aes
+{
+public:
+	static constexpr size_t BlockSize = 16;
 
-	static std::unique_ptr<SymmetricCipher> CreateNoOp();
+	static MemoryView Encrypt(const AesKey256Bit&		  Key,
+							  const AesIV128Bit&		  IV,
+							  MemoryView				  In,
+							  MutableMemoryView			  Out,
+							  std::optional<std::string>& Reason);
 
-	static std::unique_ptr<SymmetricCipher> CreateAes();
+	static MemoryView Decrypt(const AesKey256Bit&		  Key,
+							  const AesIV128Bit&		  IV,
+							  MemoryView				  In,
+							  MutableMemoryView			  Out,
+							  std::optional<std::string>& Reason);
 };
 
 void crypto_forcelink();
-- 
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