The TSEC/KL-7, code named ADONIS, was a rotor machine encryption system introduced in the 1950s by the United States National Security Agency. It had eight rotors, seven of which moved in a complex pattern. The non-moving rotor was in the middle of the stack. It replaced the SIGABA system developed during World War II. The KL-7 was designed for off-line operation. It was about the size of a teletype machine and had a similar three-row keyboard, with shift keys for letters and figures. The KL-7 produced printed output on narrow paper strips that were then glued to message pads. When encrypting, it automatically placed a space between each five-letter code group. There was an adaptor available, the KLX-7, that allowed 5-level Baudot punched paper tape from teletype equipment to be read for decryption. The standard KL-7 had no ability to punch tapes. A variant of the KL-7, the KL-47, could also punch paper tape, allowing direct input to teleprinters. {| border="1" cellspacing="0" align="left" style="margin: 0 1em 0 0;" | {| border="0" style="margin: 0 0 0 0" | |- | |- | align="center" | Both sides of a KL-7 rotor |} |} Each rotor had 36 contacts. To establish a new encryption setting, operators would select a rotor and place it in a plastic outer ring at the correct offset. The rings to use for each position and the offset was specified in a printed key (cryptography) list. This process would be repeated eight times until all rotor positions were filled. Key settings were usually changed every day at midnight, GMT. The basket containing the rotors was removable, and it was common to have a second set of rotors and basket, allowing the rotors to be set up prior to key change. The old basket could then be kept intact for most of the day to decode messages sent the previous day, but received after midnight. The rotor basket had two sets of connectors at each end that mated with the main assembly. One pair of connectors, with 26 pins each, connected to the keyboard and printer. Another pair, with 10 pins each, connected through the mechanism used to control the stepping of the rotors. There was also a switch under each movable rotor that was operated by cams on its plastic outer ring. Different outer rings had different arrangements of cams. The exact way all these features worked together is not publicly known, but it is likely they advanced the rotors in a pseudorandom fashion, a design principle that had proved successful with SIGABA. One former KL-7 operator relates that the rotor stepping was independent of the plaintext or ciphertext input [http://www.jproc.ca/crypto/kl7.html]. There was a sliding permutor board under the keyboard that may have been used to switch the input and output of the basket, so that the same rotor setup could be used both to encrypt and decrypt messages. The KL-7 was largely replaced by electronic systems such as the KW-26 ROMULUS and the KW-37 JASON in the 1970s, but KL-7s were kept in service as backups and for special uses. In 1967, when John Anthony Walker (a sailor in the U.S. Navy) walked into the embassy of the Soviet Union in Washington, DC seeking employment as a spy, he carried with him a copy of a key list for the KL-47. KL-7s were compromised at other times as well. A unit captured by North Vietnam is on display at NSA's National Cryptologic Museum. After the Walker spy ring was uncovered in 1985, remaining KL-7's and KL-47's were withdrawn from service and decommissioned. Canada's last KL-7-encrypted message was sent on June 30, 1983, "after 27 years of service." ==See also== * NSA encryption systems * Typex ==Sources== * [http://www.jproc.ca/crypto/kl7.html Jerry Proc's page on the KL-7] * [http://www-users.cs.york.ac.uk/matthew/KL-7.html Information collected on the KL-7 from various sources] Rotor machines
I took out the link to Walker spy ring beause the story is told in the John Anthony Walker link. I don't think a second article would is needed, maybe redirect. --User:ArnoldReinhold 15:41, 27 Sep 2004 (UTC) : Sure; I've added the redirect too. User:Matt Crypto 15:45, 27 Sep 2004 (UTC) ==Two rings or one?== Currently we have this description:
See other meanings of words starting from letter:
Words begining with KL-7:
KL-7
KL-7
KL-7
The TSEC/KL-7, code named ADONIS, was a rotor machine encryption system introduced in the 1950s by the United States National Security Agency. It had eight rotors, seven of which moved in a complex pattern. The non-moving rotor was in the middle of the stack. It replaced the SIGABA system developed during World War II. The KL-7 was designed for off-line operation. It was about the size of a teletype machine and had a similar three-row keyboard, with shift keys for letters and figures. The KL-7 produced printed output on narrow paper strips that were then glued to message pads. When encrypting, it automatically placed a space between each five-letter code group. There was an adaptor available, the KLX-7, that allowed 5-level Baudot punched paper tape from teletype equipment to be read for decryption. The standard KL-7 had no ability to punch tapes. A variant of the KL-7, the KL-47, could also punch paper tape, allowing direct input to teleprinters. {| border="1" cellspacing="0" align="left" style="margin: 0 1em 0 0;" | {| border="0" style="margin: 0 0 0 0" | |- | |- | align="center" | Both sides of a KL-7 rotor |} |} Each rotor had 36 contacts. To establish a new encryption setting, operators would select a rotor and place it in a plastic outer ring at the correct offset. The rings to use for each position and the offset was specified in a printed key (cryptography) list. This process would be repeated eight times until all rotor positions were filled. Key settings were usually changed every day at midnight, GMT. The basket containing the rotors was removable, and it was common to have a second set of rotors and basket, allowing the rotors to be set up prior to key change. The old basket could then be kept intact for most of the day to decode messages sent the previous day, but received after midnight. The rotor basket had two sets of connectors at each end that mated with the main assembly. One pair of connectors, with 26 pins each, connected to the keyboard and printer. Another pair, with 10 pins each, connected through the mechanism used to control the stepping of the rotors. There was also a switch under each movable rotor that was operated by cams on its plastic outer ring. Different outer rings had different arrangements of cams. The exact way all these features worked together is not publicly known, but it is likely they advanced the rotors in a pseudorandom fashion, a design principle that had proved successful with SIGABA. One former KL-7 operator relates that the rotor stepping was independent of the plaintext or ciphertext input [http://www.jproc.ca/crypto/kl7.html]. There was a sliding permutor board under the keyboard that may have been used to switch the input and output of the basket, so that the same rotor setup could be used both to encrypt and decrypt messages. The KL-7 was largely replaced by electronic systems such as the KW-26 ROMULUS and the KW-37 JASON in the 1970s, but KL-7s were kept in service as backups and for special uses. In 1967, when John Anthony Walker (a sailor in the U.S. Navy) walked into the embassy of the Soviet Union in Washington, DC seeking employment as a spy, he carried with him a copy of a key list for the KL-47. KL-7s were compromised at other times as well. A unit captured by North Vietnam is on display at NSA's National Cryptologic Museum. After the Walker spy ring was uncovered in 1985, remaining KL-7's and KL-47's were withdrawn from service and decommissioned. Canada's last KL-7-encrypted message was sent on June 30, 1983, "after 27 years of service." ==See also== * NSA encryption systems * Typex ==Sources== * [http://www.jproc.ca/crypto/kl7.html Jerry Proc's page on the KL-7] * [http://www-users.cs.york.ac.uk/matthew/KL-7.html Information collected on the KL-7 from various sources] Rotor machines
KL-7
I took out the link to Walker spy ring beause the story is told in the John Anthony Walker link. I don't think a second article would is needed, maybe redirect. --User:ArnoldReinhold 15:41, 27 Sep 2004 (UTC) : Sure; I've added the redirect too. User:Matt Crypto 15:45, 27 Sep 2004 (UTC) ==Two rings or one?== Currently we have this description:
Each rotor consisted of a double ring of contacts. To establish a new encryption setting, operators would select an inner ring with 10 contacts and place it in the 26-contact outer ring at the correct offset as specified in the key (cryptography) list. This process would be repeated eight times until all rotor positions were filled. The outer ring permuted the message text; the inner ring controlled the stepping of the rotors in a pseudorandom fashion, a design principle that had proved successful with SIGABA.Do we have a source for this information? I'm skeptical about having two concentric rings — the photo on [http://www-users.cs.york.ac.uk/matthew/KL-7.html] shows a single ring of 36 contacts. User:Matt Crypto 12:42, 13 Oct 2004 (UTC) ''I think you are correct. The photo does show 36 contacts on a single rotor, thought the caption says 26. One source talked about an inner and outer ring, but I now think that must refer to the plastic indexing ring. There are two sets of contacts on the basket (26 and 10) and the sources say that the 10 went to the stepping solonoids. I'm not sure how this works. One has to insure that a signal on the 26 pin input goes to a signal on the 26 pin output. There is also the question of how figs and ltrs shift was done. I've seen other sources that say SIGABA encoded space to "Z" and the KL-7 may have used a similar arangement. Anyway, I've changed the text,'' --User:ArnoldReinhold 13:37, 13 Oct 2004 (UTC) Thanks. Sorry to be nitpicky, but I'm also unsure about
a 10-pin set was used to control the the stepping of the rotors in a pseudorandom fashion, a design principle that had proved successful with SIGABA.I presume this was based on this quote: "''Each side of the rotor basket has two groups of 26 contacts and 10 contacts. The 26 contacts make connection to the circuit board and then onto the keyboard. The 10 contacts however make contact only with the KLA Stepping unit where an internal wiring harness routed the signal path back to the 10 contacts on the other side. This was called the reentry circuits for a more secure system''" — [http://webhome.idirect.com/%7Ejproc/crypto/kl7.html] Other parts from the above source and other sources suggest that the stepping was controlled by the outer plastic rings, which contain a series of indentations. My personal interpretation is although the 10 contacts make contact with the Stepping Unit, they don't contribute to the stepping; instead, they just pass through wires across it back to the other side and back into the rotor assembly again; this then results in a 26-element permutation (perhaps "26-point"?) using 36 contact rotors (this idea is illustrated at the very bottom of [http://www-users.cs.york.ac.uk/matthew/KL-7.html]). User:Matt Crypto 14:27, 13 Oct 2004 (UTC) ''I've been thinking about that too. I agree that the feedback scheme makes sense (is that your page?) but I also suspect it is used to control stepping as well. Elsewhere it is pointed out that the steping is controlled by 7 electromagnets. It would make sense to use 7 of the 10 feedback lines to step the rotors as well. That would follow the SIGABA design. The plastic rings are involved, but they are what the solonoids engage. Let me sleep on it.'' --User:ArnoldReinhold 02:29, 17 Oct 2004 (UTC) ''I have some more ideas. There are only 29 characters in Baudot that would actually participate in cryptography: blank (no punches), DEL (all punches) and BEL would presumabley not be used. They encode no information. There are 7 cam-controlled switches in the KL7 rotor box. It may not be a coincidence that 29+7=36, the number of contacts on the rotors. Perhaps only 7 of the group of 10 contacts are fed back. That would create a permutation of 29 elements, just right for encoding Baudot. The 7 feedback lines could also be connected through the switches to the rotor advance solonoids, the switch on one rotor would presumably control a different rotor. I don't know if the plastic cams were all the same, but if they weren't, that would add another keying element. For the purposes of the article, however, it might be best to say we don't know.'' --User:ArnoldReinhold 14:53, 18 Oct 2004 (UTC) : Yes, I think for the article we need to be conservative about what we express as fact, particularly when there's not much available in the way of sources. (The web link is indeed my page, by the way). I like your idea about the 29-character alphabet, but I'm a little unsure about the stepping being controlled by the feedback lines. This would make the stepping dependent on the plaintext/ciphertext. There's a practical problem: recovery from transmission errors is much more involved. It's safe to assume that there'd be occasional corrupted characters in transmission. In other rotor machines that we know about, including the SIGABA, the stepping is fixed regardless of the plaintext. If a ciphertext character is corrupted then only one character is corrupted in the decrypted message. However, for a machine that uses plaintext to control the stepping, then a transmission error is much more difficult to recover from. Moreover, there's also a theoretical issue that some plaintexts would produce weak stepping patterns. For these two reasons, I'd be quite surprised if the NSA had employed this type of mechanism in the KL-7. User:Matt Crypto 15:30, 18 Oct 2004 (UTC) ''I agree that making the cipher dependent on plaintext is not a good design, but there are two eyewitness reports that suggest single character garbles did ruin the decryption. But then the garbles could have been multi character in nature e.g. "WT" for a Morse code "J". My comments about Baudot above are wrong, by the way. All punches is DEL in ASCII, it's FIGS in Baudot. And BELL is a FIGS-shifted character, so its code is not ignored. My 29+7 idea no longer adds up. I've edited the text to reflect the uncertainty, which is probably where things should stand. I did add a sentence about the permutor board shown on the Canadian web site. I'm trying to puzzle it out in detail. It seems to be slid back and forth by the knob to the left of the keyboard.''--User:ArnoldReinhold 19:59, 18 Oct 2004 (UTC) : A recent post on the Yahoo "cryptocollectors" group provides some more anecdotal evidence on this topic:
Special Note: If an incorrect letter was typed during Encypher or Decypher the KL-7 did NOT lose Crypto Key synchronization; it only produced one incorrect letter!! The rotors would step once or remain stationary each cycle depending on their "Notch" cams regardless of which letter key was typed.If this source is correct, then the KL-7 stepping was independent of the message. User:Matt Crypto 12:24, 30 Nov 2004 (UTC)
See other meanings of words starting from letter:
K
KA | KB | KC | KD | KE | KF | KG | KH | KI | KJ | KL | KM | KN | KO | KP | KR | KS | KT | KU | KW | KX | KY | KZ |Words begining with KL-7:
KL-7
KL-7
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