Codes for Cubs and Scouts

Block cipher

We write the message in a rectangular block, one row at a ime, and then read off the columns.

Example:

To encode the message THIS IS VERY EASY!, write it in a block like this:

THISI       
SVERY      
EASY!

The coded message is read by looking at the columns, and writing them out like this: TSE HVA IES SRY IY!

To decode it, just write all the code words in a block again, as columns, and then read the message across the rows.