TY  - BOOK
AU  - Singh,Simon
TI  - The cracking codebook: how to make it, break it, hack it, crack it 
SN  - 000717604X
PY  - 2004///
CY  - London
PB  - Harper Collin's Children's Book
KW  - Coding theory
KW  - sears
KW  - Cryptography
N1  - Includes bibliographical references
ER  -