Adding Flags API

src/api/MicCheck.Api/ApiKeys/ApiKeyHasher.cs

@@ -0,0 +1,22 @@
+using System.Security.Cryptography;
+using System.Text;
+
+namespace MicCheck.Api.ApiKeys;
+
+public static class ApiKeyHasher
+{
+    public static string Hash(string key)
+    {
+        var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(key));
+        return Convert.ToHexString(bytes).ToLowerInvariant();
+    }
+
+    public static string GenerateKey()
+    {
+        var bytes = RandomNumberGenerator.GetBytes(32);
+        return Convert.ToBase64String(bytes)
+            .TrimEnd('=')
+            .Replace('+', '-')
+            .Replace('/', '_');
+    }
+}