Go to GCHQ homepage
 ABOUT US  RECRUITMENT  PRESS OFFICE  CODEBREAKING

Puzzle 4: answers

This random cipher alphabet was used:

Cipher: A B C D E F G H I J K L M
Plain: P E T L S J X D Q A R H I
Cipher: N O P Q R S T U V W X Y Z
Plain: V G F O Z M C Y K N U B W

The message can then be decoded as follows:

Cipher: ZBDDH QWBPQ KHBTM ALBKM WOCLM ESBEE
Plain: WELLD ONEFO RDECI PHERI NGTHI SMESS
Cipher: JOBXE MWOPK BIXBW TUJWJ DUEME ZBLQA
Plain: AGEUS INGFR EQUEN CYANA LYSIS WEHOP
Cipher: BUQXL JNBPQ XWHQX KTQHB YKBJV MWOAJ
Plain: EYOUH AVEFO UNDOU RCODE BREAK INGPA
Cipher: OBEMW PQKSJ CMNBJ WHLJN BYBBW JYDBC
Plain: GESIN FORMA TIVEA NDHAV EBEEN ABLET
Cipher: QZQKV CLKQX OLCLB AXRRD BEAKQ NMHBH
Plain: OWORK THROU GHTHE PUZZL ESPRO VIDED
Cipher: CLJWV UQXPQ KNMEM CMWOQ XKZBY EMCB
Plain: THANK YOUFO RVISI TINGO URWEB SITE

Therefore, the final plain text solution is "WELL DONE FOR DECIPHERING THIS MESSAGE USING FREQUENCY ANALYSIS. WE HOPE YOU HAVE FOUND OUR CODEBREAKING PAGES INFORMATIVE AND HAVE BEEN ABLE TO WORK THROUGH THE PUZZLES PROVIDED. THANK YOU FOR VISITING OUR WEBSITE".

 Go back to: Puzzle 4

 Top of page

 More puzzles
More puzzles can be found on the website of Southampton University's School of Mathematics, which hosts a National Cipher Challenge.