| Project 6, 2015 | Research Experience for Teachers | Project 4, 2016 |
|---|---|---|
| Substitution Cipher |
|
The text in the field labeled "encrypted:" is (or is close to being) a
famous quote that is encrypted by permuting the letters A-Z, and
characters space, comma and single quote. The JComboBoxes at the
bottom of the applet represent a guess at the permutation that was
used to encrypt. Make selections and click the "Decrypt" button.
For example, if you think that the encrypted character A
maps to the plaintext character D then open the list
in the JComboBox labeled A and select D.
Always click the "Decrypt" button after making selections to
register the change. When the "Decrypt" button is clicked, the
translation to plaintext is shown in the "decrypted:" field. However,
if a JComboxBox setting is - (the default
for all characters) then there will be no translation to plaintext
for that character and blank spaces will occupy the plaintext positions
corresponding to that character's position in the "encrypted:" field.
To get a new permutation while leaving the message the same click the "New Key" button. To get a new quote while not changing the permutation, click the "New Message" button. To get a new quote and a new permutation click both buttons. |
Why this?
|
It may seem that these types of ciphers are fairly secure since the
number of possible permutations of the characters is roughly
2626 which is about 1036 so it is impractical
for an attacker to be able to crack the permutation by doing a search
over all possible permutations. However, as can be seen by using this
applet and some human intelligence, these ciphers can be broken readily.
This applet allows a key change for the current message. There is nothing special about this - you just may see things better with a different key. |