%%s 3/3/67
%%d D 1.2 15-Jun-83 10:47:20 sventek 2 1
%%c Removed trailing periods from quoted strings, as they are no longer needed.
%%s 0/0/0
%%d D 1.1 25-Mar-82 12:03:09 v1.1 1 0
%%c Version 1.1 is the Spring 1982 Distribution of the LBL/Hughes release
%%c of the Software Tools Virtual Operating System software and documentation.
%%T
%%I 1
%%D 2
#-h- crypt.r          934  asc  25-mar-82 07:31:15  v1.1 (sw-tools v1.1)
%%E 2
%%I 2
#-h- crypt.r          937  asc  15-jun-83 10:47:06  sventek (joseph sventek)
%%E 2
#-h- defns             56  asc  25-mar-82 07:30:51  v1.1 (sw-tools v1.1)
 # definitions for crypt tool
 
 define(MAXKEY,MAXLINE)
%%D 2
#-h- main             538  asc  25-mar-82 07:30:52  v1.1 (sw-tools v1.1)
%%E 2
%%I 2
#-h- main             537  asc  15-jun-83 10:46:44  sventek (joseph sventek)
%%E 2
 # crypt - encrypt and decrypt standard input

 DRIVER(crypt)
 character getc, xor
 character c, key(MAXKEY), b
 integer getarg, mod
 integer i, keylen

%%D 2
 string usestr "usage:  crypt key."
%%E 2
%%I 2
 string usestr "usage:  crypt key"
%%E 2
  
 call query(usestr)
 keylen = getarg(1,key,MAXKEY)
 if (keylen == EOF)
	call error(usestr)
 for (i=1; getc(c) != EOF; i = mod(i,keylen) + 1)
	{
	if (c < ' ')		#leave control characters alone
		call putc(c)
	else
		{
		b = xor(c, key(i) & 31)
      		if (b == 127)		#DEC can't handle RUBOUT char
      			b = c
		call putc(b)
		}
	}
 DRETURN
 end
#-h- xor              121  asc  25-mar-82 07:30:55  v1.1 (sw-tools v1.1)
 # xor - exclusive-or of a and b
 character function xor(a,b)
 character a, b
  
 xor = (a & !b) | (!a & b)
 return
 end
#-h- crypt.fmt        873  asc  25-mar-82 07:31:18  v1.1 (sw-tools v1.1)
.so ~bin/manhdr
.hd Crypt (1) 15-Jan-79
crypt and decrypt standard input
.sy
crypt key
.ds
crypt encrypts characters on the standard input by using 'key'.
The file can eventually be decrypted by running it back through
crypt with the same key.
Double encryption (encrypting a file with first one key and then
another) is allowable, but on some systems the decryption must
be done in the exact reverse order as encryption was done.
 
The encryption algorithm used by 'crypt' is not a complicated one, so
users requiring a great degree of protection should not rely on
this tool.
.fl
none
.sa
.di
.au
Original from Kernighan & Plauger's 'Software Tools', with modifications
by Debbie Scherrer.  (NOTE:  the original encryption algorithm has been
altered slightly.)
.bu
On IAS and VMS systems, double encryption must be decrypted in the
exact reverse order as the encryption.
%%E 1