Vigenère Cipher

Encode and decode messages using the classic Vigenère polyalphabetic cipher. A CTF essential.

Input

Output


                            

                            

                                
                                
                            

                        

                    


                    

                        
Vigenère Table

                        

                            

                        

                    

                


                

                    

                        
How Vigenère Works

                        
                            
                        
                    

                    

                        
The Vigenère cipher uses a keyword to shift each letter by different amounts. Unlike Caesar
                            cipher (single shift), Vigenère cycles through the keyword, making it harder to crack.

                        
Example: Key "KEY" with text "HELLO" → H+K, E+E, L+L, L+K, O+E
                            → RIJVS