Singh, Simon. <br/><br/>
The cracking codebook :  how to make it, break it, hack it, crack it / 
by Simon Singh. 
 - London :  Harper Collin's Children's Book,  2004. 
 - 258 p. : ;  25 cm. 
<br/><br/>Includes bibliographical references. 
<br/><br/><label>ISBN: </label>000717604X 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Coding theory.<br/>Cryptography.