PURPLE: 2nd Problem

Munitions Buildings, Washington D.C.

28 September 1940

Dear Delia Ann Taylo

We intercepted a circular report encrypted with
the Purple machine that goes around the embassies.
It is urgent to decipher it. Fortunately, we know
the key of the day:

MOBPXY - AQKSWZLHCDIJUGREFTVN

Good luck!

Frank B. Rolett,

XFTZF BSVMO RSHEE PURBW JJUQR EVNDP JAGHJ

BBRWB XOSUQ SBGNV DVDYE VHZZE INVNK LCGSJ

VSZQF JUCGD WCGTJ LDHEP QJFHG UYRLD LNKKP

YBAKH RVZCF UMYDR QWACR RZUVP IVHSP MSTZL

EUAGT VYXGO IHINQ OMYVH JDDQU HMGNU RRGSG

AFFCI CMLUH VRTLD KMVAH JKCWO OHEET SHHUN

ZQJDX PHSAU WFLMY U