Transposition Cipher is a free and reliable application which will allow the encryption and decryption of data using irregular columnar transposition.

The Key button permits settting of a numeric key which is one dimension of the transposition rectangle and this must be set before you can encrypt or decrypt data (the other dimension is calculated automatically).

Our implementation of this cipher can cope quite happily regardless of the ratio between the key and the data length, and will encrypt and decrypt data with a variable second dimension without difficulty.

Using the Open Plaintext or Open Ciphertext buttons on the tool bar, you may open a standard text (.txt) file or Transposition Cipher text (.tpc) file for processing. The size of the file in bytes, and the file name and path, are displayed on the status bar. Using the Close Plaintext or Close Ciphertext buttons, the data stores and displays are cleared.

The Encrypt and Decrypt buttons will allow processing of the source data after first stripping away any spaces, punctuation and numbers. Please note that you must load the source data into the correct pane. If you are encrypting, load the plaintext source into the upper pane. If decrypting, load the ciphertext source into the lower pane.
Print buttons are available to allow the printing of the contents of both the Plain and Cipher text panes.
Using the Save Plaintext or Save Ciphertext buttons on the tool bar, you may save pane contents to a standard text (.txt) file or Transposition Cipher text (.tpc) file, as appropriate.

There is no file size limit in Transposition Cipher although your operating system and memory configuration may impose such limits. Menu options include functions similar to the toolbar, along with various help options.