TheCodeBreakers
Many inventors also invoke the vast number of combinations of keys
afforded by their system as proof of its invulnerability. To exhaust the
possible solutions would take eons, they contend. Of course the
argument is specious. With 26 letters, an enormous number of different
cipher alphabets is available for monoalphabetic substitution—
403,291,461,126,605,635,584,000,000, to be exact. If a cryptanalyst
tried one of these every second, he would need six quintillion years to
run through them all. That is longer than the known universe has been
in existence. Yet most monoalphabetics are solved in a matter of
minutes. The reason, as mathematician Claude Shannon has shown, is
that the cryptanalyst does not go after these possibilities one by one. He
eliminates millions at a time. Moreover, the trials progress from the more
probable to the less probable hypotheses, increasing the cryptanalyst's
chance of striking the right one early
annaabi.ee 
