Giovan Battista Bellaso Is Credited with the Introduction of the Method All the Way Back

Vigenere Cipher

 Giovan Battista Bellaso is credited with the introduction of the method all the way back in 1553.  Blaise de Vigenere later received credit in the 19th century and we now know this method as the Vigenere Cipher.

We take plaintext and with a keyword we cipher that original word into ciphertext.

A=1, Now a keyword may have to repeat if the keyword is shorter than the plaintext.

Here is a quick example: Plaintext: CABIN Keyword: BEEBE (See I had to begin to repeat the keyword and add the letters “BE” again because the keyword of “BEE” was shorter than the plaintext of “CABIN”) Ciphertext: EEFJR

Another example: Plaintext: WAND Keyword: BEST Ciphertext: XEFW

Your turn: Plaintext: POTTER KEYWORD: SIRIUS Ciphertext: Let’s Recap What We Learned Today!

Internet Tips

 Be careful of other people online, not everyone is who they say they are online.  Remember “If it is too good to be true, then it probably is” also applies to the internet.  Don’t jump to share your personal information online.  Viruses can come from just about everywhere online.  Don’t bully other people on the internet.  Before you download or install ask if it is okay to do so.  Keep your wireless networks password protected.  How you behave online is an extension of yourself so behave the same way you would in person.

Passwords

 Don’t use any personal information in your password.  Don’t use a word in the dictionary as your password.  Don’t share passwords except with a parent or guardian.  Do use combinations of letters, numbers, and symbols!  Make your passwords at least 8 characters long!

Steganography

 Steganography is not the study of the Stegosaurus, if you learned anything from me today let it be this!  Steganography is when a computer file has a hidden message within that file.