Added internal RandomId generator

Pandatech.Crypto.Tests/Aes256Tests.cs

@@ -2,16 +2,6 @@ namespace Pandatech.Crypto.Tests;
 
 public class Aes256Tests
 {
-    [Fact]
-    public void Generate_ShouldReturnByteArray()
-    {
-        const int length = 16;
-        var randomBytes = Random.GenerateBytes(length);
-
-        Assert.NotNull(randomBytes);
-        Assert.Equal(length, randomBytes.Length);
-    }
-
     [Fact]
     public void EncryptDecryptWithParameter_ShouldReturnOriginalString()
     {

Pandatech.Crypto.Tests/RandomTests.cs

@@ -0,0 +1,51 @@
+namespace Pandatech.Crypto.Tests;
+
+public class RandomTests
+{
+    [Fact]
+    public void Generate_ShouldReturnByteArray()
+    {
+        const int length = 16;
+        var randomBytes = Random.GenerateBytes(length);
+
+        Assert.NotNull(randomBytes);
+        Assert.Equal(length, randomBytes.Length);
+    }
+
+    [Fact]
+    public void GeneratePandaId_WithZeroPreviousId_ReturnsValidId()
+    {
+        const long previousId = 0;
+        for (var i = 0; i < 1_000_000; ++i)
+        {
+            var newId = Random.GeneratePandaId(previousId);
+
+            Assert.True(newId is > 1_000_000 and < 1_000_037);
+        }
+    }
+
+    [Fact]
+    public void GeneratePandaId_WithNonZeroPreviousId_ReturnsIncrementedId()
+    {
+        const long previousId = 1_000_000;
+        for (var i = 0; i < 1_000_000; ++i)
+        {
+            var newId = Random.GeneratePandaId(previousId);
+
+            Assert.True(newId > previousId);
+        }
+    }
+
+    [Fact]
+    public void GeneratePandaId_WithinReasonableIterations_DoesNotProduceDuplicates()
+    {
+        long previousId = 0;
+
+        for (var i = 0; i < 1_000_000; ++i)
+        {
+            var id = Random.GeneratePandaId(previousId);
+            Assert.NotEqual(previousId, id);
+            previousId = id;
+        }
+    }
+}

Pandatech.Crypto/Pandatech.Crypto.csproj

@@ -4,14 +4,14 @@
         <TargetFramework>net7.0</TargetFramework>
         <ImplicitUsings>enable</ImplicitUsings>
         <Nullable>enable</Nullable>
-        <Version>2.1.1</Version>
+        <Version>2.1.2</Version>
         <Title>Pandatech.Crypto</Title>
         <Authors>Pandatech</Authors>
         <PackageIcon>pandatech.png</PackageIcon>
         <PackageReadmeFile>Readme.md</PackageReadmeFile>
         <Description>PandaTech.Crypto is a .NET library simplifying common cryptograhic functions.</Description>
         <RepositoryUrl>https://github.com/PandaTechAM/be-lib-pandatech-crypto</RepositoryUrl>
-        <PackageReleaseNotes>AES256 encrypted byte array sequence changed</PackageReleaseNotes>
+        <PackageReleaseNotes>Added Random Id Generator for internal use</PackageReleaseNotes>
     </PropertyGroup>
 
     <ItemGroup>

Pandatech.Crypto/Random.cs

@@ -19,4 +19,18 @@ public static string GenerateAes256KeyString()
         rng.GetBytes(buffer);
         return Convert.ToBase64String(buffer);
     }
+
+    public static long GeneratePandaId(long? previousId)
+    {
+        var random = GenerateBytes(4);
+        var randomValue = BitConverter.ToInt32(random, 0) & 0x7FFFFFFF;
+        var randomOffset = randomValue % 36 + 1;
+
+        if (previousId is 0 or null)
+        {
+            return 1_000_000 + randomOffset;
+        }
+
+        return (long)(previousId + randomOffset)!;
+    }
 }