From a British report:
But for the astonishing insecurity of NFAK 621 in confiding in officers outside the organisation, who would not appreciate the need for absolute secrecy, ourselves should probably never have received any reliable information.Certain messages (e.g. those bearing an indicator which had already been recovered) could probably be dealt with by "WAGNER" on the spot; other problems were passed back to OKH to be tested on the "analytical machine" and the results sent to WAGNER.
If this theory is correct, and on the evidence there seems very little reason to doubt it, it is clear that METTIG and probably HUETTENHAIN could tell us far more than they have chosen to say. Whether the knowledge was confined to a few people in OKH and OKW, or whether the results were passed to other departments, it is at present impossible to judge.
It remains to consider the more serious question of whether the Germans ,were able to exploit Typex without compromised drums. It appears that machines ware captured at DUNKIRK without ,drums and were kept in OKW. There is no evidence that they ever saw a plugboard, although they must have "known of its existence and of the ,other complications of procedure from captured orders. .Again, the Abwehr assignment at the beginning of 1944 suggests that they captured no machines subsequent to North Africa. Ignoring BODE' s unconfirmed statement that Typex was exploited prior to DUNKIRK, how much reliance can we place on HAUNHORST’s statement that NFAK 621 had had sporadic success in 1941 ? It should be noted that this statement was made in reply to a question on "high-grade'' traffic, and not specifically on Typex. It probably relates to the now known breaking of Cypher "W’’.
There is insufficient evidence to answer this question. It is clear, however, that if the North African story is true, OKH must have had extensive machinery ready to cope with such a situation, and had presumably used such machinery in an attempt to break earlier traffic. These are the researches at OKH and OKW referred to in the OKM documents. HUETTENHAIN's statement that OKW had not studied the indicator system, coming from the head of the research section, is too simple to be credible and is at variance with the OKM document quoted above.
It appears that HUETTENHAIN has mislead us on the subject of Typex. Great emphasis is laid on the idea that they considered enigma, and therefore Typex insoluble. Why then, did they devote so much time to the study of enigma and attempts to produce a securer type of machine ? No German would credit the statement that we made no attempt to solve German enigma because we believed Typex to be insoluble. It is clear that they had little doubt in the theoretical solubility of Typex at least in the earlier part of the war. Interrogations have so far failed to elicit whether they had any practical success, and what stage they reached in their researches. At present we can only say that Typex with five compromised solid drums and no plugboard was soluble and was quite probably solved.
22nd September 1945
I'll write more on this soon...