Technical data

Fig. 1. Flowchart of key generation

The work of the key generating center consists of the statistical control stage

and the key generation stage.

Statistical control stage

Once the program has been launched, the physical random number generator is

tested. The statistical checking uses at least 10000 bits of information by special

criteria described below. If the sequence does not satisfy these criteria, a signal is sent

to restart the random number generator board. If these tests fail for three times, the

work of the center is stops. If the tests are successful, the binary sequence is divided

into non-overlapping segments 64 bits each, and each segment passes a test that

consists of a sequence of statistical criterions. If the test is unsuccessful, the next 64

bits are taken from the random number generator, and the procedure repeats. If any

three in 64-bit segments in a row fail to satisfy the statistical criteria, the program

stops.

Key generation stage

At this stage, a sequence consisting of 100 random digits is created. The

duration of this stage is 50 cycles, and at least 400 bits, generated by the random

number generator, are required. A sequence of random numbers that have passed the

statistical control stage, is divided into 8-bit sections and is sent to the input of the

converter.

Let's describe how the converter works. Let b

represent the 1

8-bit of this

sequence

50,1i

. The converter converts the pair b

2i-1

into a 4-digit decimal

number k

25,1i

using the following rule:

65535

)256(10000

212 ii

Thus, during two cycles of operation, 4 digits of the key are generated. The

outcome of the stage of key generation is a sequence of values k

, k

, …, k

EST

Conve

rter