Problem 10 Playfair cipher cryptanalysis

Decrypt the following ciphertext that was encrypted using a Playfair cipher. You will need to research on our own how this cipher works since we did not discuss it in class. Show all your work; including a description of any software you used and what you used it for in case you did any programming for your solution. If you wish to submit source code, please include it as text at the end of the PDF file containing your answers to the written problems. Answers without satisfactory explanation and documentation of how they were obtained will receive no credit. Neither will answers obtained by simply running Playfair decryption from an online crypto applet or website on the ciphertext.

A text file containing the ciphertext can be downloaded from the assignments page.

Hint: the letter J is omitted from the alphabet to obtain the required 5 5 key square.

DBFNE XTZMF TOVBQ BQTOB XAOFP RTZEQ RHQKQ VDXOK ABPRQ

IELTV KEEXX SFSBP WDBOB YBFRO EABOR HQKQV TXGUE LABTH

TRXNO NEAAY XHBOH NEXBS HRQBZ MSEXP HFGZU GKCBD POEAA

YXHBO XPHFK RQIAB PRQIE LBXFZ BISEF XPBRA PRQIW CBRXD

YGTBQ TEAAY XHBOH NEXBS HRQBP RQIEL BXBTH BQBNF SISEB

XNUXP BURBX BQROX BATBR HBPWD RPROG UGXQR SEZYO XBAEL

AXCWB YBASX RKROP RHBOP BDPIC NOXEM RPKRX TELAX CWEQF

ZSXEL RHROP RHBUX DASEX NZNGU ELBXF SDGDB TBZLV ERHBO

RQ