Poskitt, Kjartan. <br/><br/>
The secret life of codes / 
Kjartan Poskitt ; [illustrated by Ian Baker] 
 - London :  Scholastic,  2010. 
 - 157 p.  ill. ;  20cm. 
 - Murderous maths .
<br/><br/><label>ISBN: </label>9781407107158 
<br/><br/><label>Nat. Bib. No.: </label>GB98V9584  bnb 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Cryptography
<br/><br/><label>Dewey Class. No.: </label>652.8