add encryption/decryption

1 files changed, 28 insertions, 0 deletions

diff --git a/lib/nes/app/crypto/sha256.hh b/lib/nes/app/crypto/sha256.hh
new file mode 100644
index 0000000..55ba202
--- /dev/null
+++ b/lib/nes/app/crypto/sha256.hh
@@ -0,0 +1,28 @@
+#pragma once
+
+#include "nes/common/containers/span.hh"
+#include "nes/common/types.hh"
+
+namespace nes::app
+{
+	class sha256
+	{
+		static constexpr auto length = u32{ 256 / 8 };
+		static constexpr auto block_size = u32{ 512 / 8 };
+
+		u8 data_[length]{};
+
+	public:
+		static auto hash(span<u8 const>) -> sha256;
+
+		auto get_data() const -> span<u8 const, length> { return data_; }
+
+	private:
+		explicit sha256();
+
+		auto combine(span<u8 const, block_size>) -> void;
+
+		auto get(u32 index) -> u32;
+		auto set(u32 index, u32 value) -> void;
+	};
+} // namespace nes::app
\ No newline at end of file