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THE NRO STAFF 14 00009099D 

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CONTHOl SYSTeM 

15 August 1968 

MEMORANDUM FOR SAFSL (COLONEL FORD) 

SUBJECT: Encryption of NRP Satellite Systems 

A brief background survey has been conducted per your 

request concerning procedures and policies for encryption 

of NRP satellite systems. ~~·~l~~~h~e~r~e~e~~~~~~~~~. 

mined policy on encryption 

NRP system is individuall y examlne on 1 

weighing the advantages and drawbacks of encryption 

the threats to the system by not encrypting. In many cases, 

the final determination is a long, arduous task that is 

determined not only by the relative security of the system, 

but also by the engineering impact of encryption. Indeed, 

the decision may be a fluid one, varying from launch to 

launch as the program progresses. 

The only written statement of policy found concerning 

encryption was one for meteorlogical satellite systems, a 

copy of which has been provided to your office. . 

Generally data has been returned on a common downlink channel for both bird health and intelligence data. 

In lieu of encryption, minimum risk has been achieved to 

peripheral stations by transponding data and transmitting 

in an analog form, low band, low power. Other procedures 

have included use of "privatized" stations protected from 

easy intercept by large, friendly land masses. 

Telemetry data is not encrypted by either the U.S. 

U.S.S.R. systems. On occasion some specific command 

systems have been encoded to minimize risk. 

or 

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If there is to be a general (or specific) rule regarding encryption, it would probably read somewhat like 

this: 

"While encryption of satellite system data 

is h i ghly desirable, a complete analysis must be 

made of each individual system concerned, carefully weighing the advantages and inherent 

d i sadvantages of encryption against the threat 

to the system by not encrypting. Due consideration must be given to the total mission of the 

system, the capabi l i ty of the system to perform 

wi th and without encryption, the threat to the 

system (to include such intangible items as 

current international situation) and the overall 

impact of encryption on system engineering." 

Captain, USAF 

Dep Asst for Security 

NRO Staff 

BYEMAN 

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