Perry E. Metzger wrote: > "Steven M. Bellovin" <[EMAIL PROTECTED]> writes: > >>Bruce Schneier's newsletter Cryptogram has the following fascinating >>link: http://www.fas.org/irp/eprint/heath.pdf >>It's the story of effects of a single spy who betrayed keys and >>encryptor designs.
[...] > One intriguing question that I was left with after reading the whole > thing was not mentioned in the document at all. One portion of the > NSA's role is to break other people's codes. However, we also have to > assume that equipment would fall into "the wrong people's hands" at > intervals, as happened with the Pueblo incident. If properly designed, > the compromise of such equipment won't reveal communications, but > there is no way to prevent it from revealing methods, which could then > be exploited by an opponent to secure their own communications. > > Does the tension between securing one's own communications and > breaking an opponents communications sometimes drive the use of COMSEC > gear that may be "too close to the edge" for comfort, for fear of > revealing too much about more secure methods? If so, does the public > revelation of Suite B mean that the NSA has decided it prefers to keep > communications secure to breaking opposition communications? Of historical interest on this question there is useful material in "Between Silk and Cyanide" by Leo Marks. Marks was responsible for ciphers used during WWII by SOE for communications with agents in German occupied Europe. He describes an episode when he was visited by people from Bletchley Park who were concerned that he was equipping agents with ciphers that (he deduced) were too strong for Bletchley Park to attack if they should fall into German hands and come into use by them. It is understandable, particularly during the Battle of the Atlantic, that UK priorities should have been to maintain the availability of breaks into enemy traffic even at the risk of hazarding communications with agents. (If Britain had failed in the Atlantic the war in the west would have been over. If SOE failed, there were no short-term consequences of similar seriousness.) The preservation of secrecy about those breaks for nearly thirty years after the end of the war suggests that those priorities may have become ossified, which may in turn account for excessive governmental anxieties over the spread of strong cryptography. Any change in these priorities would be of great interest. Nicholas Bohm -- Salkyns, Great Canfield, Takeley, Bishop's Stortford CM22 6SX, UK Phone 01279 871272 (+44 1279 871272) Fax 020 7788 2198 (+44 20 7788 2198) Mobile 07715 419728 (+44 7715 419728) PGP public key ID: 0x899DD7FF. Fingerprint: 5248 1320 B42E 84FC 1E8B A9E6 0912 AE66 899D D7FF --------------------------------------------------------------------- The Cryptography Mailing List Unsubscribe by sending "unsubscribe cryptography" to [EMAIL PROTECTED]