Java Program to Perform Cryptography Using Transposition Technique
Cryptography using the Transposition Technique can be done by using Transposition ciphers which uses the letters of the plaintext message and after that, they permute the order of the letters. The Columnar Transposition Cipher is a form of transposition cipher just like Rail Fence Cipher. Columnar Transposition involves writing the plaintext out in rows, and then reading the ciphertext off in columns one by one.
It should be easy to spot a transposition cipher because the letter frequencies should mimic the usual frequencies for English – high frequencies for a,e, i, n, o r, s, t. But, cryptanalysis of a transposition cipher might be difficult. The essential technique is anagramming which is rearranging the ciphertext letters to “make sense. The key to the cipher is the pattern of rearrangement. In mathematically terms it can simply be assumed that a bijective function is used on the characters’ positions to encrypt and an inverse function to decrypt.
Example 1Input : Plaintext : how are you Output : Ciphertext : a e oowu hyr
Example 2Input : Plaintext : you are a champion Output : Ciphertext : h aa ep o nuc i yaorm
Implementation: Given a plain-text message and a numeric key, cipher/de-cipher the given text using Columnar Transposition Cipher. ‘Hello Geek’ is custom input taken as plain text!
Cipher Text : l-o-G-ekl-e-He -