.TH DES 1  "24 March 1987".SH NAMEdes - DES file encryption.SH SYNOPSIS.PP.B des -e|-d [-h] [-k key] [-b].SH DESCRIPTION.B desis a filter that encrypts or decrypts standard input to standard outputwith the Data Encryption Standard (DES).Either -e (encrypt) or -d (decrypt) must be specified. If the key is notgiven on the command line with the -k option the command will prompt for ittwice, suppressing echo and comparing the two responses to guard againstmistyping..PThe -h flag controls how the key string is to be interpreted.Without the -h flag, the key is an ASCII string.Since DES ignores the loworder bit of each key byte, thehigh order bit is set for odd parity, thus retaining the information containedin the low order bit.If the -h flag is set, the key string is interpreted as16 hex/ASCII characters; the low order bit of each byte is again ignored as perthe DES algorithm.This allows the use of any arbitrary 56-bit key, including bytes representingcontrol characters that could not be typed if the -h option were not used..PPBy default, DES Cipher Block Chaining (CBC) mode is used, with an initialvector (IV) of all zeros; if the -b option is specified, Electronic CodeBook (ECB) mode is used instead..PPExcept for the -h option, this command is compatible with the.B descommand on the Sun Microsystems workstation..SH "SEE ALSO"Sun Microsystems DES(1) manual page, which describes in detail howthe length of the file is encoded in the last block of ciphertext..SH AUTHORPhil Karn, KA9Q