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Topic: Convert ascii wifi key to hex

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WDef

Group: Members
Posts: 798
Joined: Sep. 2005

Posted: Sep. 22 2007,23:37

Continuing explorations, may be of limited interest to anyone else but at least I'll know where to find it again.

Doing away with while and read:

Code Sample

#!/bin/bash

#
# hex2ascikey.sh
# Takes hex wifi key as argument and prints asci
#
echo -n $1 | sed 's/[0-9A-Fa-f]//g
t message
:message s/.\*/Ignoring non-hex chars &\n/'

echo -n $1 | sed 's/[^0-9A-Fa-f]//g; s/../\"%s\\x&\"/g' | xargs printf

echo

I'm not really sure why that t branching test works quite as it does. So thought I'd try to do without it and let sed take over:

Code Sample

#!/bin/bash

#
# hex2ascikey.sh
# Takes hex wifi key as argument and prints asci
#

echo -n $1 | sed '
H
s/[0-9A-Fa-f]//g
/[^0-9A-Fa-f]/{
s/^/\"Ignoring non-hex chars \"/
}
x
s/[^0-9A-Fa-f]//g
s/../\"%s\\x&\"/g
s/^/"%s\n"/
G
' | xargs printf

echo

WDef

Group: Members
Posts: 798
Joined: Sep. 2005

Posted: Sep. 23 2007,09:12

Or Sed-free, parse char-by-char:

Code Sample

#
# hex2ascikey.sh
# Takes hex wifi key as argument and prints asci
#

ASC=""
IGNORED=""
igntemp=`mktemp`

echo -n $1 | while read -n 1 CH; do

case $CH in
[0-9A-Fa-f])
ASC="${ASC}${CH}"
if [ ${#ASC} -eq 2 ]; then
printf "%s\x$ASC"
ASC=""
fi;;
*) IGNORED="${IGNORED}${CH}"
;;
esac
echo ${IGNORED} >${igntemp}
done
echo
echo "Ignored non-hex chars `cat ${igntemp}`"
rm -f ${igntemp}

Slower, even without the temp file.

WDef

Group: Members
Posts: 798
Joined: Sep. 2005

Posted: Sep. 23 2007,11:07

Bettter: no subshell, no read, no temp file.

Still less efficient than sed, but then sed is made to do this stuff.

Code Sample

#!/bin/bash

#
# hex2ascikey.sh
# Takes hex wifi key as argument and prints asci
#

ASC=""
IGNORED=""

A="$1"

until [ ${#A} -eq 0 ]; do
B=${A#?}
CH=${A%%$B}

case $CH in
[0-9A-Fa-f])
ASC="${ASC}${CH}"
if [ ${#ASC} -eq 2 ]; then
printf "%s\x$ASC"
ASC=""
fi;;
*) IGNORED="${IGNORED}${CH}"
;;
esac
A=${B}
done

echo
[ -n "${IGNORED}" ] && echo "Ignored non-hex chars ${IGNORED}"

WDef

Group: Members
Posts: 798
Joined: Sep. 2005

Posted: Oct. 06 2007,21:18

Yes, I know, (groan), "he still hasn't given up on this thread".

(Pls bear with me while I post my self-education exercises).

Much easier in C:

Code Sample

//~ asci2hex - converts ascii wifi key to hex

#include <stdio.h>

main()
{
char ch;
printf("Enter the ascii key: ");
while ( ch= ' ' ){
ch = getchar();
if (ch == '\n')
break;
printf("%X", ch);
}
printf("\n");
}

And (todo: doesn't yet report any ignored non-hex input):

Code Sample

//~ asci2hex - converts hex wifi key to ascii

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>

char hexToAscii(char first, char second)
//~ http://snippets.dzone.com/posts/show/2073
{
char hex[3], *stop;
hex[0] = first;
hex[1] = second;
hex[2] = 0;
return strtol(hex, &stop, 16);
}

main()
{
char ch1, ch2;

printf("Enter the hex key: ");
while (1){
ch1 = getchar();
if (ch1 == '\n')
break;
if (!isxdigit(ch1))
continue;
ch2 = getchar();
if (ch2 == '\n')
break;
if (!isxdigit(ch2))
continue;
printf("%c", hexToAscii(ch1, ch2));
}
printf("\n");
}

13 replies since Sep. 18 2007,12:33

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Damn Small Linux Board » Non-DSL Topics » Programming and Scripting » Convert ascii wifi key to hex