how to decryption this security method( tab code).

Question

 this is enpcryption code 

 

 

char[,] ch = new char[,] {{'a','b','c','d','e','f'},

 

{'g','h','i','j','k','l'},

{'m','n','o','p','q','r'},

{'s','t','u','v','w','x'},

{'y','z','1','2','3','4'}};

for (int i = 0; i < textBox1.Text.Length; i++)

{

for (int j = 0; j < 5; j++)

{

for (int k = 0; k < 6; k++)

{

if (textBox1.Text[i] == ch[j,k])

{

k = k + 1;

j = j + 1;

for (int s = 0; s < j; s++)

{

textBox2.Text += "*";

}

textBox2.Text += " ";

for (int l = 0; l < k; l++)

{

textBox2.Text += "*";

}

textBox2.Text += " ";

}

}

if (textBox1.Text[i] == ' ')

{

textBox2.Text += " ";

}

}

}

}