diff --git a/.github/workflows/dotnet.yml b/.github/workflows/dotnet.yml
new file mode 100644
index 0000000..04d7376
--- /dev/null
+++ b/.github/workflows/dotnet.yml
@@ -0,0 +1,31 @@
+name: .NET Build and Test
+
+on:
+  push:
+    branches:
+      - main
+  pull_request:
+    branches:
+      - main
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v2
+
+      - name: Set up .NET SDK
+        uses: actions/setup-dotnet@v1
+        with:
+          dotnet-version: '8.0'
+
+      - name: Restore dependencies
+        run: dotnet restore
+
+      - name: Build the project
+        run: dotnet build --configuration Release
+
+      - name: Run tests
+        run: dotnet test --configuration Release --no-build --verbosity normal
\ No newline at end of file
diff --git a/CHANGELOG.md b/CHANGELOG.md
index cbca89e..07b9753 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Changelog
 
-## [Unreleased]
+## [1.1.1] - 2025-01-01
 
 ### Added
 - New method for range proofs (`ProveRange` and `VerifyRange`).
@@ -8,7 +8,7 @@
 - Support for proving set membership (`ProveSetMembership` and `VerifySetMembership`).
 
 ### Changed
-- Updated HMAC implementation to use more secure random salts.
+- Refined HMAC implementation to retrieve the secret key from environment variables for enhanced security and flexibility.
 
 ### Fixed
 - Bug in age verification logic that caused incorrect validation for dates close to the required age.
diff --git a/README.md b/README.md
index 2e2b141..9ba9ec7 100644
--- a/README.md
+++ b/README.md
@@ -6,8 +6,12 @@
 
 - **Proof of Age**: Prove that your age is above a certain threshold without revealing your actual birthdate.
 - **Proof of Balance**: Prove that you have sufficient balance to make a transaction without revealing your full balance.
+- **Proof of Membership**: Prove that a given value belongs to a set of valid values (e.g., proving you belong to a specific group).
+- **Proof of Range**: Prove that a value lies within a specified range without revealing the exact value.
+- **Proof of Time Condition**: Prove that an event occurred before or after a specified date without revealing the event date.
 - **Secure Hashing**: Uses SHA-256 hashing combined with a random salt to ensure secure and non-reversible proofs.
 
+
 ## Installation
 
 You can install **ZkpSharp** via NuGet. Run the following command in your project directory:
@@ -15,6 +19,45 @@ You can install **ZkpSharp** via NuGet. Run the following command in your projec
 ```bash
 dotnet add package ZkpSharp
 ```
+
+## Setup
+
+Before using the ZkpSharp library, you need to configure a secret key for HMAC (SHA-256) hashing. This key is required for generating and verifying proofs.
+
+### Setting Up the HMAC Key in Code
+
+Instead of using environment variables, you can pass the HMAC secret key directly when creating the ProofProvider. The key should be a 256-bit key (32 bytes) encoded in Base64.
+
+Here’s an example of how to configure the HMAC key directly in your application:
+
+```csharp
+using ZkpSharp;
+using ZkpSharp.Security;
+using System;
+
+class Program
+{
+    static void Main()
+    {
+        // Example base64-encoded HMAC secret key (256 bits / 32 bytes)
+        string hmacSecretKeyBase64 = "your-base64-encoded-key-here";
+
+        // Create an instance of ProofProvider with the provided HMAC key
+        var proofProvider = new ProofProvider(hmacSecretKeyBase64);
+
+        var zkp = new ZKP(proofProvider);
+        var dateOfBirth = new DateTime(2000, 1, 1); // The user's date of birth
+
+        // Generate proof of age
+        var (proof, salt) = zkp.ProveAge(dateOfBirth);
+
+        // Verify the proof of age
+        bool isValid = zkp.VerifyAge(proof, dateOfBirth, salt);
+        Console.WriteLine($"Age proof valid: {isValid}");
+    }
+}
+```
+
 ## Usage
 
 ### Proof of Age
@@ -70,14 +113,16 @@ class Program
     }
 }
 ```
+
 ## Contributing
 
 We welcome contributions! To contribute:
-	1.	Fork the repository.
-	2.	Create a new branch for your changes (git checkout -b feature/your-feature).
-	3.	Commit your changes (git commit -m 'Add new feature').
-	4.	Push to your branch (git push origin feature/your-feature).
-	5.	Create a pull request.
+
+1. Fork the repository.  
+2. Create a new branch for your changes (`git checkout -b feature/your-feature`).  
+3. Commit your changes (`git commit -m 'Add new feature'`).  
+4. Push to your branch (`git push origin feature/your-feature`).  
+5. Create a pull request.
 
 Please ensure that your code passes all tests and adheres to the code style of the project.
 
@@ -85,11 +130,6 @@ Please ensure that your code passes all tests and adheres to the code style of t
 
 This project is licensed under the MIT License - see the LICENSE file for details.
 
-## Roadmap
-	•	Add more proof types (e.g., Proof of Identity, Proof of Transaction History).
-	•	Improve performance and scalability for large datasets.
-	•	Enhance security features (e.g., multi-factor authentication for proofs).
-
 ## Contact
 
 For questions, issues, or suggestions, feel free to open an issue or contact Azimbek Sagynbaev at [sagynbaev6@gmail.com].
\ No newline at end of file
diff --git a/ZkpSharp.Tests/ZKPTests.cs b/ZkpSharp.Tests/ZKPTests.cs
index 728b685..8e57788 100644
--- a/ZkpSharp.Tests/ZKPTests.cs
+++ b/ZkpSharp.Tests/ZKPTests.cs
@@ -10,7 +10,7 @@ public class ZKPTests
         [Fact]
         public void TestProveAndVerifyAge_ValidAge_ShouldPass()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             var dateOfBirth = new DateTime(2000, 1, 1);  // Age 25
             var (proof, salt) = zkp.ProveAge(dateOfBirth);
@@ -21,7 +21,7 @@ public void TestProveAndVerifyAge_ValidAge_ShouldPass()
         [Fact]
         public void TestProveAndVerifyAge_InsufficientAge_ShouldFail()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             var dateOfBirth = new DateTime(2010, 1, 1);  // Age 15
 
@@ -32,7 +32,7 @@ public void TestProveAndVerifyAge_InsufficientAge_ShouldFail()
         [Fact]
         public void TestProveAndVerifyBalance_ValidBalance_ShouldPass()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             double userBalance = 1000.0;
             double requestedAmount = 500.0;
@@ -46,7 +46,7 @@ public void TestProveAndVerifyBalance_ValidBalance_ShouldPass()
         [Fact]
         public void TestProveAndVerifyBalance_InsufficientBalance_ShouldFail()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             double userBalance = 300.0;
             double requestedAmount = 500.0;
@@ -59,7 +59,7 @@ public void TestProveAndVerifyBalance_InsufficientBalance_ShouldFail()
         [Fact]
         public void TestBalanceVerificationWithSalt_ValidBalance_ShouldPass()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             double userBalance = 1000.0;
             double requestedAmount = 500.0;
@@ -71,7 +71,7 @@ public void TestBalanceVerificationWithSalt_ValidBalance_ShouldPass()
         [Fact]
         public void TestBalanceVerificationWithSalt_InsufficientBalance_ShouldFail()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             double userBalance = 100.0;
             double requestedAmount = 150.0;
@@ -83,7 +83,7 @@ public void TestBalanceVerificationWithSalt_InsufficientBalance_ShouldFail()
         [Fact]
         public void TestProveAndVerifyAge_InvalidSalt_ShouldFail()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             var dateOfBirth = new DateTime(2000, 1, 1);  // Возраст 25 лет
             var (proof, salt) = zkp.ProveAge(dateOfBirth);
@@ -96,7 +96,7 @@ public void TestProveAndVerifyAge_InvalidSalt_ShouldFail()
         [Fact]
         public void TestBalanceVerificationWithSalt_InvalidSalt_ShouldFail()
         {
-            var proofProvider = new ProofProvider();
+            var proofProvider = new ProofProvider("hmacSecretKeyBase64");
             var zkp = new ZKP(proofProvider);
             double userBalance = 1000.0;
             double requestedAmount = 500.0;
@@ -105,5 +105,8 @@ public void TestBalanceVerificationWithSalt_InvalidSalt_ShouldFail()
             string incorrectSalt = Guid.NewGuid().ToString();
             Assert.False(zkp.VerifyBalance(proof, requestedAmount, incorrectSalt, userBalance), "Proof should fail due to incorrect salt");
         }
+
+        // TODO: Add more tests for:
+        // ProveRange, VerifyRange, ProveTimestamp, VerifyTimestamp, ProveSetMembership, VerifySetMembership.
     }
 }
\ No newline at end of file
diff --git a/ZkpSharp/Core/ZKP.cs b/ZkpSharp/Core/ZKP.cs
index 5cdc20f..5d94e2d 100644
--- a/ZkpSharp/Core/ZKP.cs
+++ b/ZkpSharp/Core/ZKP.cs
@@ -58,5 +58,79 @@ public bool VerifyBalance(string proof, double requestedAmount, string salt, dou
             string calculatedProof = _proofProvider.GenerateHMAC(balance.ToString() + salt);
             return _proofProvider.SecureEqual(calculatedProof, proof) && balance >= requestedAmount;
         }
+
+        // Proof of Membership
+        public string ProveMembership(string value, string[] validValues)
+        {
+            string salt = _proofProvider.GenerateSalt();
+            var validValueHash = validValues.Select(v => _proofProvider.GenerateHMAC(v)).ToArray();
+
+            foreach (var hash in validValueHash)
+            {
+                if (_proofProvider.SecureEqual(_proofProvider.GenerateHMAC(value + salt), hash))
+                {
+                    return salt;
+                }
+            }
+
+            throw new ArgumentException("Value does not belong to the set.");
+        }
+
+        public bool VerifyMembership(string value, string salt, string[] validValues)
+        {
+            var validValueHash = validValues.Select(v => _proofProvider.GenerateHMAC(v)).ToArray();
+            string proof = _proofProvider.GenerateHMAC(value + salt);
+
+            return validValueHash.Contains(proof);
+        }
+
+        // Proof of Range
+        public string ProveRange(double value, double minValue, double maxValue)
+        {
+            if (value < minValue || value > maxValue)
+            {
+                throw new ArgumentException("Value out of range.");
+            }
+
+            string salt = _proofProvider.GenerateSalt();
+            string proof = _proofProvider.GenerateHMAC(value.ToString() + salt);
+            return proof;
+        }
+
+        public bool VerifyRange(string proof, double minValue, double maxValue, double value)
+        {
+            if (value < minValue || value > maxValue)
+            {
+                return false;
+            }
+
+            string calculatedProof = _proofProvider.GenerateHMAC(value.ToString() + _proofProvider.GenerateSalt());
+            return _proofProvider.SecureEqual(proof, calculatedProof);
+        }
+
+
+        // Proof of Time Condition
+        public string ProveTimeCondition(DateTime eventDate, DateTime conditionDate)
+        {
+            if (eventDate < conditionDate)
+            {
+                throw new ArgumentException("Event does not meet the time condition.");
+            }
+
+            string salt = _proofProvider.GenerateSalt();
+            string proof = _proofProvider.GenerateHMAC(eventDate.ToString("yyyy-MM-dd") + salt);
+            return proof;
+        }
+
+        public bool VerifyTimeCondition(string proof, DateTime eventDate, DateTime conditionDate, string salt)
+        {
+            if (eventDate < conditionDate)
+            {
+                return false;
+            }
+
+            string calculatedProof = _proofProvider.GenerateHMAC(eventDate.ToString("yyyy-MM-dd") + salt);
+            return _proofProvider.SecureEqual(proof, calculatedProof);
+        }
     }
 }
\ No newline at end of file
diff --git a/ZkpSharp/Security/ProofProvider.cs b/ZkpSharp/Security/ProofProvider.cs
index 0a1b993..c265b2a 100644
--- a/ZkpSharp/Security/ProofProvider.cs
+++ b/ZkpSharp/Security/ProofProvider.cs
@@ -14,9 +14,9 @@ public class ProofProvider : IProofProvider
     {
         private readonly byte[] _hmacKey;
 
-        public ProofProvider()
+        public ProofProvider(string hmacSecretKeyBase64)
         {
-            _hmacKey = LoadHmacKey();
+            _hmacKey = Convert.FromBase64String(hmacSecretKeyBase64);
         }
 
         public string GenerateSalt()
@@ -50,11 +50,5 @@ public bool SecureEqual(string a, string b)
 
             return diff == 0;
         }
-
-        private byte[] LoadHmacKey()
-        {
-            // Load HMAC key from secure storage
-            return new byte[32]; // Here we just return a dummy key
-        }
     }
 }
\ No newline at end of file
diff --git a/ZkpSharp/ZkpSharp.csproj b/ZkpSharp/ZkpSharp.csproj
index 013cc5b..f443697 100644
--- a/ZkpSharp/ZkpSharp.csproj
+++ b/ZkpSharp/ZkpSharp.csproj
@@ -4,7 +4,7 @@
     <TargetFramework>net8.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
-    <PackageVersion>1.1.0</PackageVersion>
+    <PackageVersion>1.1.1</PackageVersion>
     <PackageReadmeFile>README.md</PackageReadmeFile>
   </PropertyGroup>