Vigenère Cipher Examples
Copy these Vigenère examples into Cipher Portal or read the decoder page for troubleshooting.
Example: HELLO with keyword KEY
Align KEY under HELLO (KEYKE). Add shifts: H+K=R, E+E=I, L+Y=J, L+K=V, O+E=S → RIJVS. Decrypt RIJVS with KEY to return HELLO.
Example: longer keyword SECRET
Portal demo text “The quick brown fox…” with keyword SECRET shows how a longer key reduces repeated shift patterns within short phrases. Load the built-in example on the homepage tool after selecting Vigenère.
Example: identical letters, different ciphertext
In HELLO, the two L letters encrypt to J and V because keyword letters Y and K differ—demonstrating why simple frequency counts fail without column splitting.
Verify in Cipher Portal
Select Vigenère on the main tool, enter plaintext and keyword for forward checks, then swap to decrypt with the same keyword to confirm RIJVS returns HELLO. Longer class assignments can use the built-in SECRET demo sentence to show how keyword length changes repetition in the ciphertext stream.
When students lack the keyword, direct them to the Vigenère cipher cracker guide for Kasiski-style reasoning before they rely on portal key recovery alone.
- Plaintext
- HELLO
- Keyword
- KEY
- Ciphertext
- RIJVS
Frequently asked questions
What is the standard Vigenère example?
HELLO encrypted with KEY yields RIJVS on Cipher Portal.
Do spaces affect the example?
Examples use contiguous letters; the tool may ignore spaces in real messages.
Where is the general examples page?
/examples.html includes Caesar and Rail Fence triples too.
How do I teach keyword recovery?
Start with known-key examples here, then introduce Kasiski on paper.