Three units were used to measure consumption: hardware binary digits
, words, and hours.
Now, how many binary digits
are needed to encode an analog signal, such as a picture or analog TV signal?
The transmitted binary digits
are decoded at the receiving end.
In the world of computing, however, data is stored as 0s and 1s (known as binary digits
, or bits).
Duobinary coding technique involves a correlation span of two binary digits
([a.sub.k], [a.sub.k - l]).
Designed and built by Paul Kocher of Cryptography Research in San Francisco and his coworkers, the new code-cracking computer incorporates more than 1,000 integrated-circuit chips specifically configured for checking the strings of 56 binary digits
that comprise DES encryption keys.
To measure the approximate entropy of the binary digits
of pi, [square root of 2], [square root of 3], and e, Pincus determined how often each of eight blocks of three consecutive digits--000, 001, 010, 011, 100, 101, 110, and 111--comes up in the first 280,000 digits of the number.
He and his coworkers succeeded in creating a potentially useful, efficient linear code based not on binary digits
(0,1) but on quaternary digits (0,1,2,3).
By designating one lobe as 0 and the other as 1, the researchers can capture the trajectory's wanderings as a sequence of binary digits
Each of four bases is given a value of either 0 or 1 to generate a string of binary digits
. Taken in groups of three, these digits are assigned specific directions on the lattice (lower left).
Thus, proof checking can be done electronically when the whole procedure is encoded as strings of binary digits
. This makes it possible to use this concept for password protocols and in cryptological games like tossing a coin by telephone or exchanging secret keys (SN:9/26/81, p.205).