The KL-7 was an off-line cipher machine, code name ADONIS, and was similar to, but more advanced than the famous German Enigma machine. It was used for the protection of exclusive (off-line) traffic. The unit had the approximate dimensions of a medium sized portable typewriter and was housed in an extruded aluminum carrying case which was painted in an olive drab, khaki colour. The dimensions of the carrying case were approximately  13.5 inches wide by 16.5 inches deep by 7 inches high.  Navy versions, were of course, navy grey and the hinged case lid opened from front to rear. On the front of the KL7, there was a character counter to help keep track of the number of characters in a message and a small lamp to illuminate the keyboard.
 

The KL-7 had eight rotors but the rotor in the # 4 position was stationery and only acted as a pass through. As a result, there are only seven windows on the rotor basket, one to view each rotor that moves. It used three type 2D21 and one 12AX7 vacuum tubes. There was one spare of each type plugged into the circuit board. Crypto-variables such as rotor and plugboard settings were referenced from a hard bound paper code book or 'flash' paper bound into a small booklet. In the Royal Canadian Navy, a complete second rotor assembly was stored in a separate box away from the machine. This assembly had the settings from the previous day and could easily be substituted into the KL-7 to decode a late arriving message from the previous day.

To encrypt a plain text message, the operator would enter the message on the keyboard and the KL7 generated a gummed tape using 5 letter groups. This tape was supplied in either 3/16" or 1/4" wide rolls about two inches in diameter. The tape was pasted on a message pad and the resultant encoded message was submitted to the Message Centre where specific information such as Routing Indicators and Date-Time-Group was added. Finally, the complete message was passed to a radio operator or a Teletype operator for transmission. To decrypt, coded messages were received in 5 letter groups. These, in turn, would be entered on the KL-7 keyboard, and the machine would generate a gummed tape with the plain language text on it. This was pasted on a message pad and given to the message Centre where it was typed up and duplicated for distribution within the ship and for filing. According to Walt Hutchens, an ex-USN coder, "the noise produced by the KL-7 rotors advancing was one of the two most distinctive sounds that I have ever heard. The other sound was the last round and the clip being ejected from an M-1 Garand".

An ex-army communicator who operated a KL-7 for 10 years, relates his impressions of the machine. "The rotors on the KL-7 did not sequence in the manner of an Engima machine, Instead, each keystroke caused all the rotors to turn simultaneously. Rotors had to be taken out of the machine, cleaned and lubricated at periodic intervals. A special oil would be applied then wiped off the rotor contacts. For each keystroke, the machine made a 'plunking' sound. An operator could not achieve any speed on the machine because one had to press very hard on the keys to get the machine to cycle. In the encode mode, the KL-7  would add a space after each five letters. The advanced design of the machine also permitted the encoding of the space character, numeric characters and also provided punctuation.

After a message was decoded, the operator first had to read the security level classification of the document. If the operator was not cleared to the correct level, he was required to stop and locate another person with sufficient clearance.  In the Comm Center itself, there was a list of personnel who cleared to be in area. No one else was allowed. Once a general had to be informed that he could not be granted access because his name was not on the list.  He did not push it at the time but the next day a revised list was received from Ottawa with his name on it".

Components for the KL-7 and its variants were manufactured in the mid 50's to the mid 60's by several United States government contracted firms and the Singer Company was a major supplier. The parts were then assembled at either the Philadelphia Army Depot or at the Bluegrass, Kentucky plant. After final assembly, the units became the property of the National Security Agency and were distributed to the various military users. All crypto machines and materials were on loan to North Atlantic Treaty Organization member countries including Canada. In addition, there was also an airborne version of the KL-7 which was modified at one of the US Air Force Security Service facilities in Mississippi for use in aircraft.

The KL-7A was a battery powered version which had a higher degree of soundproofing to counter the problems produced by the acoustics of the machine. Batteries were not intended for portability, but for technical security reasons. Since the machine had a high TEMPEST and acoustical signature, there were concerns that it might be 'exploitable'. TEMPEST is an unclassified term that describes the vulnerability of an electronic device to having the classified components of its design intercepted and exploited. A machine that does not process classified information does not have a TEMPEST problem, only a radio frequency interference problem. Acoustical signature describes those systems which make an audible sound (sonic or subsonic or ultrasonic) which is repetitive and identifiable to certain specific functions. If these sounds are recorded from a distance, it is potentially feasible to compromise the machine.

After the Walker family spy ring was exposed in the mid 1980's, it was found that they had supplied the Soviet Union with a complete working KL-7 and all keying materials. Immediately, all KL-7's were withdrawn from service and returned to the COMSEC depot at Ft. Mead Maryland. This included all code books, spare parts, manuals and any other paraphernalia associated with the unit. The system had been in service with the Royal Canadian Navy for 27 years.

All of the crypto gear fitted on Canadian ships in the 1950's and 1960's was owned by the National Security Agency of the United States and was loaned to North Atlantic Treaty Organization member countries including Canada. Also included, was keying material, key lists, certain rotors, and key cards. This material came in a variety of editions depending upon the application. Examples of these crypto packages would be named CANUSEYESONLY, CANUKUS, AUSCANUKUS, NATO, ALLIED, and so on. Some of it was CANEYESONLY and would have been generated in Canada by the Communications Security Establishment.

The above information was documented by cobbling  recollections from many individuals.

SPECIFICATIONS:

Keying Method: Rotors, keylist.
Input: Keyboard
Output: Printed, dry gummed, paper tape.
Speed: 12 to 15 wpm.
Applications: Off-line , strategic and tactical environments.

This is the last message encrypted by the "ADONIS" off-line system and was sent by the Royal Canadian Navy on July 1, 1983. A copy of this message can be viewed at the MARCOM Museum in Halifax.

 R 302359Z JUNE 83
FM NDHQ OTTAWA                    SSO COMM
TO CFCCHQ OTTAWA//COMD//
FMCHQ ST HUBERT//SSO SIG//
MARCOMHQ HALIFAX//SSO SIG//
AIRCOM WINNIPEG//D COS C AND E//
COMMGR LAHR//COMD//
CFSCE KINGSTON//COMD//
INFO MARPACHQ ESQUIMALT//SO COMM//
BT
UNCLAS DGCFO 052
SUBJ: TSEC/KL 7 ADONIS OFF-LINE CRYPTOGRAPHIC EQUIPMENT
RETIREMENT - LAST MESSAGE

1. THIS IS THE LAST MESSAGE SENT ON THE STRATEGIC MESSAGE SYSTEM USING THE TSEC/KL7 ADONIS OFF-LINE CRYPTOGRAPHIC EQUIPMENT.
ALTHOUGH THIS MESSAGE IS UNCLASSIFIED, SPECIAL ARRANGEMENTS WERE MADE TO HAVE IT OFF-LINE ENCRYPTED.

2. AFTER 27 YEARS OF SERVICE IN THE STRATEGIC AND TACTICAL ENVIRONMENTS OF THE ROYAL CANADIAN NAVY AND THE CANADIAN FORCES, THE TSEC/KL7 ADONIS GOES OUT OF SERVICE AT 302359Z JUNE 83 AND WILL BE REPLACED MY A MORE MODERN SYSTEM.

3. ARRANGEMENTS HAVE BEEN MADE FOR COPIES OF THIS MESSAGE TO GO TO THE C AND E AND MARITIME MUSEUMS. A COMPLETE TSEC/KL7 ALONG WITH MANUALS WILL ALSO BE PLACED IN THE C AND E AND MARITIME MUSEUMS WHEN IN DUE COURSE IT BECOMES UNCLASSIFIED.
BT
CONF TOR 010012Z JULY 83 CL

These superb photos of the KL-7 assembly (above) and the AC power converter (below) were supplied by John Alexander, G7GCK Leicester, England. The KL-7 is shown in the "sanitized" condition with rotors missing and identification plates rendered illegible.

This view of the KL-7 accessory rack shows the placement of the power converter and spares case. (Photo courtesy of John Alexander)

---

This section features the KL-7 which is displayed at the MARCOM Museum in Halifax. All photos by Jerry Proc.
 

A top view of the machine with the rotor assembly removed. Note the row of tube shields at the rear of the machine. The printer is mounted on the left side while the character counter is above the upper right hand side of the keyboard.
 

This view shows the contact arrangement for the rotor assembly. There are no rotors installed.
 
 

A close-up of the printer assembly. The plain text output was printed on a dry-gummed paper tape.

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