libs: begin adding capacity for doing crypto on generic os (using externally-preset keys)

libraries/libvapours/include/vapours/crypto/impl/crypto_block_cipher.hpp

@@ -0,0 +1,33 @@
+/*
+ * Copyright (c) Atmosphère-NX
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#pragma once
+#include <vapours/common.hpp>
+#include <vapours/assert.hpp>
+#include <vapours/util.hpp>
+#include <vapours/crypto/crypto_memory_compare.hpp>
+#include <vapours/crypto/crypto_memory_clear.hpp>
+
+namespace ams::crypto::impl {
+
+    template<typename T>
+    concept BlockCipher = requires(T &t, const void *cv, void *v, size_t sz, bool b) {
+        { T::BlockSize                  } -> std::convertible_to<size_t>;
+        { t.EncryptBlock(v, sz, cv, sz) } -> std::same_as<void>;
+        { t.DecryptBlock(v, sz, cv, sz) } -> std::same_as<void>;
+    };
+
+}