.\" SCCSID: @(#)makekey.8	8.1	9/11/90.TH makekey 8.SH Namemakekey \- generate encryption key.SH Syntax.B /usr/lib/makekey.SH Description.NXR "makekey command".NXR "encryption key" "generating"The.PN makekeycommandimproves the usefulness of encryption schemes depending on a key byincreasing the amount of time required to search the key space.  Itreads 10 bytes from its standard input, and writes 13 bytes on itsstandard output.  The output depends on the input in a way intended tobe difficult to compute (that is, to require a substantial fraction ofa second)..PPThe first eight input bytes(the.IR "input key" )can be arbitrary ASCII characters.The last two (the.IR salt )are best chosen from the set of digits, uppercase and lowercaseletters, the period (.), and the slash (/).The salt characters are repeated as the first two characters of the output.The remaining 11 output characters are chosen from the same set as the saltand constitute the.I "output key.".PPThe transformation performed is essentially the following:the salt is used to select one of 4096 cryptographicmachines all based on the National Bureau of StandardsDES algorithm, but modified in 4096 different ways.Using the input key as key,a constant string is fed into the machine and recirculated a number of times.The 64 bits that come out are distributed into the66 useful key bits in the result..PPThe.PN makekeycommand is intended for programs that perform encryption (for instance,.MS ed 1 .Usually input and output of.PN makekeywill be pipes..SH See Alsoed(1)