### The Best Card Trick?

Time for a little mathemagic! Choose any five cards from a pack and show four of them to your partner. How can they work out the fifth?

### Substitution Cipher

Find the frequency distribution for ordinary English, and use it to help you crack the code.

### Secret Transmissions

How can Agent X transmit data on a faulty line and be sure that her message will get through?

# Substitution Transposed

##### Stage: 3 and 4 Challenge Level:

This problem follows on from Substitution Cipher and Transposition Cipher

Below is a secret message. It's been double encrypted, first using a substitution cipher and then using a transposition cipher. Can you decipher it?

whhujnjwuzlwvvdhgdlkqwdhvdkelqhldwurlhhwklwwuhdwdgqjkhzqqbrhowkgbqkq
ywhuovwfzebzlhhzfwrlkwrhddhhhkdqsqhkkuohkrfqqdujdbjdvulhgoidpwggvhlg
vwqdhollduwzudhwqqhhrwqmguqzrzlljykrzyaprgxuidlqdwfrhhwlhfdppvhduwwv
kerukuwuhvldwqwbkgfkhgbrdkwsnpgrdkufrdrogpxllkwhhduqhhrrowohrvogrdoc
pggugouodvdghzrxvbrhlwderdhqiohddqjdqrwqkquxwggurujbwkphoxdhgluldfhi
qhfvwhdrvubpfhokrqzfqkxddqjvbornghdofkrwlseqgldvlwijgogklqvosrvffxxy
kuosozzwyvgrxrrdgehhrddddlhhduvwirovxguqvvewqsqb


If you want to work on a computer, you can download the ciphertext as a text file here.

You can then use our Cipher Challenge Toolkit to help you decrypt it.

If you are interested in code breaking you might enjoy the Secondary Cipher Challenge.