diff --git a/Security/DependencyInjection.cs b/Security/DependencyInjection.cs
index d3d4b38..4ddceb6 100644
--- a/Security/DependencyInjection.cs
+++ b/Security/DependencyInjection.cs
@@ -6,11 +6,29 @@ using Mirea.Api.Security.Common.Interfaces;
 using Mirea.Api.Security.Services;
 using System;
 using System.Collections.Generic;
+using System.Text;
 
 namespace Mirea.Api.Security;
 
 public static class DependencyInjection
 {
+    private static ReadOnlyMemory<byte> NormalizeKey(string key, int requiredLength)
+    {
+        var keyBytes = Encoding.UTF8.GetBytes(key);
+
+        if (keyBytes.Length < requiredLength)
+        {
+            var normalizedKey = new byte[requiredLength];
+            Array.Copy(keyBytes, normalizedKey, keyBytes.Length);
+            return new ReadOnlyMemory<byte>(normalizedKey);
+        }
+
+        if (keyBytes.Length > requiredLength)
+            Array.Resize(ref keyBytes, requiredLength);
+
+        return new ReadOnlyMemory<byte>(keyBytes);
+    }
+
     public static IServiceCollection AddSecurityServices(this IServiceCollection services, IConfiguration configuration)
     {
         var saltSize = int.Parse(configuration["SECURITY_SALT_SIZE"]!);
@@ -61,8 +79,13 @@ public static class DependencyInjection
             providers.Add(provider, (clientId, secret));
         }
 
-        services.AddSingleton(provider => new OAuthService(provider.GetRequiredService<ILogger<OAuthService>>(), providers,
-            configuration["SECURITY_ENCRYPTION_TOKEN"]!));
+        services.AddSingleton(provider => new OAuthService(
+            provider.GetRequiredService<ILogger<OAuthService>>(),
+            providers,
+            provider.GetRequiredService<ICacheService>())
+        {
+            SecretKey = NormalizeKey(configuration["SECURITY_ENCRYPTION_TOKEN"]!, 32)
+        });
 
         return services;
     }
diff --git a/Security/Services/OAuthService.cs b/Security/Services/OAuthService.cs
index 929f1b7..a0a5964 100644
--- a/Security/Services/OAuthService.cs
+++ b/Security/Services/OAuthService.cs
@@ -20,6 +20,8 @@ namespace Mirea.Api.Security.Services;
 
 public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider, (string ClientId, string Secret)> providers, string secretKey)
 {
+    public required ReadOnlyMemory<byte> SecretKey { private get; init; }
+
     private static readonly Dictionary<OAuthProvider, OAuthProviderUrisData> ProviderData = new()
     {
         [OAuthProvider.Google] = new OAuthProviderUrisData
@@ -101,9 +103,9 @@ public class OAuthService(ILogger<OAuthService> logger, Dictionary<OAuthProvider
         return userInfo?.MapToInternalUser();
     }
 
-    private static string GetHmacString(RequestContextInfo contextInfo, string secretKey)
+    private string GetHmacString(RequestContextInfo contextInfo)
     {
-        var hmac = new HMACSHA256(Encoding.UTF8.GetBytes(secretKey));
+        var hmac = new HMACSHA256(SecretKey.ToArray());
         return Convert.ToBase64String(hmac.ComputeHash(
             Encoding.UTF8.GetBytes($"{contextInfo.Fingerprint}_{contextInfo.Ip}_{contextInfo.UserAgent}")));
     }