ビデオ	担当者：森川 博之・山口 英・村井 純 第02回 10/18/2000

Caesar Cipher

• Each plaintext characters is replaced by a character k to the right
  
  
  • IBM ⇒ HAL (k=25)
    
    
  • C=E(p)=(p+k) mod 26
    
    
  • Only 25 choices! Not hard to break by brute force
    
    
  • “Jngpu bhg sbe Oehghf!”
    
    ⇒　 “Watch out for Brutus!”