◆ SpookStack

~ oo. . . . ij ae y . wibine rome ve ~ ~~ "Office Meniora Um + UNITED STATES GOVERNMENT To : kek TT. off . DATE: August 31, 1951 V/ From + C.F, sungacT: INFORMANT _ O CODED MESSAGES SENT BY . ’ % Don nad MACLEAN AND BURGESS [Attention is directed to a memorandum from Mr. NICHOLS to Ur. LADD Gated July 26, 1951 concerning cryptographic ideas de- veloped by SRAM on three messages sent by MACLEAN and B British officials who mysteriously disappeared recently in Europe. EMD submitted a strip of paper containing the letters of yy the three messages, and words developed by him from these letters. He also submitted a sheet of paper contsining the three messages, suspicious aspects of these messages, and his decipherment theory, This material has been listed in the Laboratory as follows: . Ql Strip of white paper bearing letters beginning TTETAEADRT R cock Qc2 Message from MacLean to his wife beginning "Had to leave unexpectedly ooome Qe3 Message from Burgess to his mother beginning "terribly sorry for my silence ...*. Qe Message from MacLean to his mother beginning 7 "I am quite all right 2... Examination in the Laboratory failed to develop any valid concealed messages. The text is very brief and consequently hampers extensive examination. These three messages seem to be fluent and reasonably free from distortion - characteristics usually absent when open code messages are effected by artifices other than double meaning. The messages could easily contain double weaning signals but the arbitrary nature of such « concealment procedure and the emall amount of text available precludes the development of valid interpretation along this line ele Pope, . “e As foray decipherment theory, his technique will provide almost any desired secret text on any arbitrarily chosen paragraph of normal English text. For example, using the first parts of the three paragraphs of Mr. NICHOLS! memorandum dated July 26, 1951 and combining them in the same manner that uses, the following words can be obtained: "ITALY AND SOVIET WiLL INFORM POWER RUSSIAN DELEGATE TO THE 11 f SECRET DAY ONE TOLD MAO". _ 393