using smaller keys sha256sums finally match

* sign/verify routine worked out (shout-out to js)

Form1.Designer.cs

@@ -120,7 +120,7 @@
             // richTextBox2
             // 
             this.richTextBox2.BorderStyle = System.Windows.Forms.BorderStyle.FixedSingle;
-            this.richTextBox2.Location = new System.Drawing.Point(12, 310);
+            this.richTextBox2.Location = new System.Drawing.Point(12, 309);
             this.richTextBox2.Name = "richTextBox2";
             this.richTextBox2.ReadOnly = true;
             this.richTextBox2.Size = new System.Drawing.Size(437, 55);
@@ -153,6 +153,7 @@
             this.button6.TabIndex = 13;
             this.button6.Text = "sign";
             this.button6.UseVisualStyleBackColor = true;
+            this.button6.Click += new System.EventHandler(this.button6_Click);
             // 
             // button7
             // 
@@ -162,6 +163,7 @@
             this.button7.TabIndex = 14;
             this.button7.Text = "verify";
             this.button7.UseVisualStyleBackColor = true;
+            this.button7.Click += new System.EventHandler(this.button7_Click);
             // 
             // textBox3
             // 

Form1.cs

@@ -6,6 +6,7 @@ using System.Drawing;
 using System.IO;
 using System.IO.Compression;
 using System.Linq;
+using System.Numerics;
 using System.Security.Cryptography;
 using System.Text;
 using System.Threading.Tasks;
@@ -51,6 +52,23 @@ namespace KRY_0x04
             return metrics;
         }
 
+        BigInteger return_bigint_representation_of_message(string input)
+        {
+            byte[] part_of_message = Encoding.ASCII.GetBytes(input);
+            return new BigInteger(part_of_message);
+        }
+
+        string return_string_representation_of_bigint(BigInteger bA_number)
+        {
+            byte[] decrypted_b_a = bA_number.ToByteArray();
+            string decrypted_text = "";
+            for (int i = 0; i <decrypted_b_a.Length; i++)
+            {
+                decrypted_text += Convert.ToString(Convert.ToChar(decrypted_b_a[i]));
+            }
+            return decrypted_text;
+        }
+
         private void button1_Click(object sender, EventArgs e)
         {
             /* load msg */
@@ -263,10 +281,97 @@ namespace KRY_0x04
                 {
                     MessageBox.Show("error: " + exc.ToString(), "error", MessageBoxButtons.OK, MessageBoxIcon.Error);
                 }
+            }     
+        }
+        
+        private void button6_Click(object sender, EventArgs e)
+        {
+            /* sign */
+            SaveFileDialog saveFileDialog1 = new SaveFileDialog();
+            saveFileDialog1.InitialDirectory = Environment.GetFolderPath(Environment.SpecialFolder.Desktop);
+            string[] keys = richTextBox2.Text.Split(' ');
+            MessageBox.Show("we good?");
+            Console.WriteLine(BigInteger.Parse(keys[1]));
+            Console.WriteLine(BigInteger.Parse(keys[0]));
+            string signed = Convert.ToString(BigInteger.ModPow(return_bigint_representation_of_message(textBox3.Text),BigInteger.Parse(keys[1]),BigInteger.Parse(keys[0])));
+
+            
+            saveFileDialog1.Title = ".sign";
+            saveFileDialog1.CheckFileExists = false;
+            saveFileDialog1.CheckPathExists = false;
+            saveFileDialog1.DefaultExt = "";
+            saveFileDialog1.FilterIndex = 2;
+            saveFileDialog1.RestoreDirectory = true;
+            if (saveFileDialog1.ShowDialog() == DialogResult.OK)
+            {
+                try
+                {
+                    File.WriteAllText(saveFileDialog1.FileName, signed);
+                    MessageBox.Show($"saved to {saveFileDialog1.FileName}", "gj, file saved!", MessageBoxButtons.OK, MessageBoxIcon.Information);
+                }
+                catch (Exception ex)
+                {
+                    MessageBox.Show("error: " + ex.ToString(), "this didn't work...", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                }
             }
-                
         }
 
-        
+        private void button7_Click(object sender, EventArgs e)
+        {
+            /* verify */
+            string[] keys = richTextBox3.Text.Split(' ');
+            string verified = "";
+            string orig_message = "";
+
+            using (OpenFileDialog dlg = new OpenFileDialog())
+            {
+                dlg.Title = "pick a .sign file";
+                /* freedom for all */
+                dlg.Filter = "sign file (*.sign)|*.sign|custom (*.*)|*.*";
+                MessageBox.Show("we still good");
+                
+                if (dlg.ShowDialog() == DialogResult.OK)
+                {
+                    try
+                    {
+                        verified = return_string_representation_of_bigint(BigInteger.ModPow(BigInteger.Parse(File.ReadAllText(dlg.FileName)), BigInteger.Parse(keys[1]), BigInteger.Parse(keys[0])));
+                    }
+                    catch (Exception excep)
+                    {
+                        MessageBox.Show("error: " + excep.ToString(), "this didn't work...", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                    }
+                }
+            }
+
+
+            using (OpenFileDialog dlg = new OpenFileDialog())
+            {
+                dlg.Title = "pick a .msg file";
+                /* freedom for all */
+                dlg.Filter = "msg file (*.msg)|*.msg|custom (*.*)|*.*";
+                
+                if (dlg.ShowDialog() == DialogResult.OK)
+                {
+                    try
+                    {
+                        orig_message = dlg.FileName;
+                    }
+                    catch (Exception excep)
+                    {
+                        MessageBox.Show("error: " + excep.ToString(), "this didn't work...", MessageBoxButtons.OK, MessageBoxIcon.Error);
+                    }
+                }
+            }
+            if (sha256sum(orig_message) == verified)
+            {
+                MessageBox.Show($"{sha256sum(orig_message)} == {verified}", "we good");
+            }
+            else
+            {
+                Console.WriteLine($"orig message: {orig_message}");
+                Console.WriteLine($"verif message: {verified}");
+                MessageBox.Show("something is seriously wrong", "checksums differ!", MessageBoxButtons.OK, MessageBoxIcon.Warning);
+            }
+        }
     }
 }

KRY-0x04.csproj

@@ -36,6 +36,7 @@
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.IO.Compression.FileSystem" />
+    <Reference Include="System.Numerics" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />