On receiving the ciphertext, the receiver who also knows the secret shift, positions his sliding ruler underneath the ciphertext alphabet and slides it to RIGHT by the agreed shift number, 3 in this case. Here is the ciphertext alphabet for a Shift of 3 − In this case, the plaintext ‘tutorial’ is encrypted to the ciphertext ‘wxwruldo’. The result of this process is depicted in the following illustration for an agreed shift of three positions. The plaintext letter is then encrypted to the ciphertext letter on the sliding ruler underneath. In order to encrypt a plaintext letter, the sender positions the sliding ruler underneath the first set of plaintext letters and slides it to LEFT by the number of positions of the secret shift. The name ‘Caesar Cipher’ is occasionally used to describe the Shift Cipher when the ‘shift of three’ is used. This number which is between 0 and 25 becomes the key of encryption. The concept is to replace each alphabet by another alphabet which is ‘shifted’ by some fixed number between 0 and 25.įor this type of scheme, both sender and receiver agree on a ‘secret shift number’ for shifting the alphabet. This cryptosystem is generally referred to as the Shift Cipher. It is a simplest form of substitution cipher scheme. It is a mono-alphabetic cipher wherein each letter of the plaintext is substituted by another letter to form the ciphertext.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |