Fix some of the more blatant bugs in the original code, provide a

BSD-able Makefile, add a man page (that also puts a bold warning about
the weakness of the encryption), and implement the -k option for
compatibility with other vendor's implementations.  (Unlike those
other vendors, we actually also document this option and its
problems.)

There are more violations of style(9) in it, like the not-use of
getopt(3), but it's not worth the while fixing all of this.

usr.bin/enigma/Makefile

@@ -1,9 +1,7 @@
-all:	enigma makekey
+PROG=	enigma
+MAN1=	enigma.1
 
-install:	enigma makekey
-	cp enigma makekey /usr/brlcad/bin/.
-	cp makekey.8 /usr/brlcad/man/man1/.
-	ln -s enigma /usr/brlcad/bin/crypt
+LINKS=	${BINDIR}/enigma ${BINDIR}/crypt
+MLINKS=	enigma.1 crypt.1
 
-clean:
-	rm -f enigma makekey *.o
+.include <bsd.prog.mk>

usr.bin/enigma/enigma.1

@@ -0,0 +1,115 @@
+.\"
+.\" enigma (aka. crypt) man page written by Joerg Wunsch.
+.\"
+.\" Since enigma itself is distributed in the Public Domain, this file
+.\" is also.
+.\"
+.\" $Id$
+.\" "
+.Dd October 30, 1998
+.Os
+.Dt enigma 1
+.Sh NAME
+.Nm enigma
+.Nd very simple file encryption
+.Sh SYNOPSIS
+.Nm
+.Op Fl s
+.Op Fl k
+.Op Ar password
+.Nm crypt
+.Op Fl s
+.Op Fl k
+.Op Ar password
+.Sh DESCRIPTION
+.Nm Enigma ,
+also known as
+.Nm crypt
+is a
+.Em very
+simple encryption program, working on a
+.Dq secret-key
+basis.  It operates as a filter, i. e. it encrypts or decrypts a
+stream of data from standard input, and writes the result to standard
+output.  It automatically detects whether the input data stream is
+already encrypted, and switches into decryption mode in this case.
+.Pp
+There are several ways to provide the secret key to the program.  By
+default, the program prompts the user on the controlling terminal for
+the key, using
+.Xr getpass 3 .
+This is the only safe way of providing it.
+.Pp
+Alternatively, the key can be provided as the sole command-line
+argument
+.Ar password
+when starting the program.  Obviously, this way the key can easily be
+spotted by other users running
+.Xr ps 1 .
+As yet another alternative,
+.Nm
+can be given the option
+.Fl k ,
+and it will take the key from the environment variable
+.Ev CrYpTkEy .
+While this at a first glance seems to be more secure than the previous
+option, it actually isn't since environment variables can also be
+examined with
+.Xr ps 1 .
+Thus this option is mainly provided for compatibility with other
+implementations of
+.Nm enigma .
+.Pp
+When specifying the option
+.Fl s ,
+.Nm
+modifies the encryption engine in a way that is supposed to make it a
+little more secure, but incompatible with other implementations.
+.Pp
+.Ss Warning
+The cryptographic value of
+.Nm
+is rather small.  This program is only provided here for compatibility
+with other operating systems that also provide an implementation.  For
+real encryption, refer to
+.Xr bdes 1
+(from the DES distribution package), or
+.Xr pgp 1
+(from the ports collection).  Hoewever, restrictions for exporting,
+importing or using such tools might exist in some countries, so those
+stronger programs are not being shipped as part of the operating
+system by default.
+.Sh ENVIRONMENT
+.Bl -tag -offset indent -width "XXCrYpTkEy"
+.It Ev CrYpTkEy
+used to obtain the secret key when option
+.Fl k
+has been given
+.El
+.Sh EXAMPLES
+.Bd -literal -offset indent
+man enigma | enigma > encrypted
+Enter key: (XXX \(em key not echoed)
+.Ed
+.Pp
+This will create an encrypted form of this man page, and store it in
+the file
+.Ql encrypted .
+.Bd -literal -offset indent
+enigma XXX < encrypted
+.Ed
+.Pp
+This displays the previously created file on the terminal.
+.Sh SEE ALSO
+.Xr bdes 1 ,
+.Xr pgp 1 ,
+.Xr ps 1 ,
+.Xr getpass 3
+.Sh HISTORY
+Implementations of
+.Nm crypt
+are very common among
+.Ux
+operating systems.  This implementation has been taken from the
+.Em Cryptbreakers Workbench
+which is in the public domain.

usr.bin/enigma/enigma.c

@@ -10,23 +10,30 @@
  *	Upgraded to function properly on 64-bit machines.
  */
 
-#define ECHO 010
+#include <sys/types.h>
+#include <sys/wait.h>
+
 #include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define MINUSKVAR "CrYpTkEy"
+
+#define ECHO 010
 #define ROTORSZ 256
 #define MASK 0377
 char	t1[ROTORSZ];
 char	t2[ROTORSZ];
 char	t3[ROTORSZ];
 char	deck[ROTORSZ];
-char	*getpass();
 char	buf[13];
 
-void	shuffle();
-void	puth();
+void	shuffle(char *);
 
 void
 setup(pw)
-char *pw;
+	char *pw;
 {
 	int ic, i, k, temp, pf[2], pid;
 	unsigned random;
@@ -97,18 +104,32 @@ char *pw;
 		t2[t1[i]&MASK] = i;
 }
 
+int
 main(argc, argv)
-char *argv[];
+	char *argv[];
 {
 	register int i, n1, n2, nr1, nr2;
-	int secureflg = 0;
+	int secureflg = 0, kflag = 0;
+	char *cp;
 
-	if (argc > 1 && argv[1][0] == '-' && argv[1][1] == 's') {
-		argc--;
-		argv++;
-		secureflg = 1;
+	if (argc > 1 && argv[1][0] == '-') {
+		if (argv[1][1] == 's') {
+			argc--;
+			argv++;
+			secureflg = 1;
+		} else if (argv[1][1] == 'k') {
+			argc--;
+			argv++;
+			kflag = 1;
+		}
 	}
-	if (argc != 2){
+	if (kflag) {
+		if ((cp = getenv(MINUSKVAR)) == NULL) {
+			fprintf(stderr, "%s not set\n", MINUSKVAR);
+			exit(1);
+		}
+		setup(cp);
+	} else if (argc != 2) {
 		setup(getpass("Enter key:"));
 	}
 	else
@@ -117,7 +138,7 @@ char *argv[];
 	n2 = 0;
 	nr2 = 0;
 
-	while((i=getchar()) >=0) {
+	while((i=getchar()) != -1) {
 		if (secureflg) {
 			nr1 = deck[n1]&MASK;
 			nr2 = deck[nr1]&MASK;
@@ -138,6 +159,8 @@ char *argv[];
 			}
 		}
 	}
+
+	return 0;
 }
 
 void
@@ -158,16 +181,3 @@ shuffle(deck)
 		deck[ic] = temp;
 	}
 }
-
-void
-puth( title, cp, len )
-char	*title;
-char	*cp;
-int	len;
-{
-	fprintf( stderr, "%s = ", title);
-	while( len-- > 0 )  {
-		fprintf(stderr, "%2.2x ", (*cp++) & 0xFF );
-	}
-	fprintf(stderr,"\n");
-}