Add blowfish algorithm (TheAlgorithms#405)

Author: Kalkwst

Algorithms.Tests/Encoders/BlowfishEncoderTests.cs

@@ -0,0 +1,44 @@
+using Algorithms.Encoders;
+using FluentAssertions;
+using NUnit.Framework;
+
+namespace Algorithms.Tests.Encoders;
+
+// Tests ported from the Java Algorithms repository
+
+public class BlowfishEncoderTests
+{
+    private BlowfishEncoder _encoder = new();
+    const string key = "aabb09182736ccdd";
+
+    [SetUp]
+    public void Setup()
+    {
+        _encoder = new BlowfishEncoder();
+        _encoder.GenerateKey(key);
+    }
+
+    [Test]
+    public void BlowfishEncoder_Encryption_ShouldWorkCorrectly()
+    {
+        const string plainText = "123456abcd132536";
+
+        const string cipherText = "d748ec383d3405f7";
+
+        var result = _encoder.Encrypt(plainText);
+
+        result.Should().Be(cipherText);
+    }
+
+    [Test]
+    public void BlowfishEncoder_Decryption_ShouldWorkCorrectly()
+    {
+        const string cipherText = "d748ec383d3405f7";
+
+        const string plainText = "123456abcd132536";
+
+        var result = _encoder.Decrypt(cipherText);
+
+        result.Should().Be(plainText);
+    }
+}