Code: Select all JUNE7TH1981JUNE7TH1981JUNE7T OURPRINCESSISINANOTHERCASTLE

(Edit: Message 5 added July 10)The American ADFGVX cipher handles the first step of encryption in a manner more complex than its German predecessor, and hopefully, is secure enough that columnar transposition isn't actually needed as a second step.In this new cipher, A, D, F, G, V and X represent the digits 0 through 5, and the order in which they are used is determined before encryption - in this example, A = 0, D = 1, F = 2, G = 3, V = 4 and X = 5, but in addition to the most familiar order of the letters, there are 719 new possibilities.The Polybius square now has expanded row and column headers - the headers which would be found in the German ADFGVX table, as well as each "shift" of the predetermined order.A key will be used with the square during encryption - "JUNE7TH1981" in this example - and written over the plaintext.From the key letter (J) move to the row containing the plaintext letter (O), using the "wrap" method from top to bottom. Since it's two rows away, the first letter of the digraph is F. Again, from the key letter, move to the column containing the plaintext letter, using the "wrap" method from left to right. It's five columns away, making the second letter of the digraph X.Note how when moving from the key letter to determine the digraph, the correct group of column/row headers is always the one that has the initial letter of the predetermined ADFGVX sequence to the left of the key letter (rows) and above it (columns).Before encrypting the next plaintext letter, switch the positions of the key and plaintext letters just used.If the key letter is the same as the plaintext letter, as is the case with the next pair of letters in the example (both U), no switch is performed. (Instead of pencil and paper, I happen to use a 3D, portable setup with movable characters that lock into place.)After encrypting the example plaintext, the ciphertext reads:I'll be posting many more than these first two here over the coming days - they all have been encrypted with the same key combinations. Columnar transposition was not performed.