| 1 | #!/usr/bin/perl |
| 2 | # -samy kamkar, rfid@samy.pl |
| 3 | |
| 4 | use strict; |
| 5 | |
| 6 | die "usage: $0 <file with data> <binary to search for>\n" unless @ARGV == 2; |
| 7 | |
| 8 | my ($file, $search) = @ARGV; |
| 9 | $search =~ s/\s//g; |
| 10 | |
| 11 | # sure, these aren't perfect, but simplifies usability if you know what you're doing |
| 12 | # if in doubt, use binary |
| 13 | |
| 14 | # binary, cool |
| 15 | if ($search =~ /^[01]+$/) { } |
| 16 | # decimal |
| 17 | elsif ($search =~ /^\d+$/) |
| 18 | { |
| 19 | $search = unpack("B*", pack("N", $search)); |
| 20 | $search =~ s/^0*//; |
| 21 | } |
| 22 | # hex |
| 23 | elsif ($search =~ /^[\da-fA-F]+$/) |
| 24 | { |
| 25 | $search = unpack("B*", pack("H*", $search)); |
| 26 | $search =~ s/^0*//; |
| 27 | } |
| 28 | # ascii |
| 29 | else |
| 30 | { |
| 31 | $search = unpack("B*", $search); |
| 32 | $search =~ s/^0*//; |
| 33 | } |
| 34 | |
| 35 | |
| 36 | # read file contents |
| 37 | open(F, "<$file") || die "Can't read $file: $!"; |
| 38 | my $data = join("", <F>); |
| 39 | close(F); |
| 40 | |
| 41 | # convert to binary |
| 42 | $data =~ s/\s//g; |
| 43 | # binary, great |
| 44 | if ($data =~ /^[01]+$/) { } |
| 45 | elsif ($data =~ /^[\da-fA-F]+$/) |
| 46 | { |
| 47 | $data = unpack("B*", pack("H*", $data)); |
| 48 | $search =~ s/^0*//; |
| 49 | } |
| 50 | else |
| 51 | { |
| 52 | die "Seriously. What sort of data is this file? Binary or hex only please.\n"; |
| 53 | } |
| 54 | |
| 55 | |
| 56 | # search every method we know how |
| 57 | print "Testing normally...\n"; |
| 58 | test_all($data, $search); |
| 59 | |
| 60 | print "Testing with flipped bits...\n"; |
| 61 | test_all($data, $search, 1); |
| 62 | |
| 63 | # now try manchester demodulating |
| 64 | my @bits = split(//, $data); |
| 65 | my $man; |
| 66 | my $last = 0; |
| 67 | for (my $i = 1; $i < @bits; $i++) |
| 68 | { |
| 69 | # if we changed, flip our bit |
| 70 | if ($bits[$i-1] == 1) |
| 71 | { |
| 72 | $last ^= 1; |
| 73 | } |
| 74 | $man .= $last; |
| 75 | } |
| 76 | |
| 77 | print "Testing with manchester demodulation...\n"; |
| 78 | test_all($man, $search); |
| 79 | |
| 80 | print "Testing with flipped manchester demodulation...\n"; |
| 81 | test_all($man, $search, 1); |
| 82 | |
| 83 | |
| 84 | sub test_all |
| 85 | { |
| 86 | my ($data, $search, $flip) = @_; |
| 87 | |
| 88 | if ($flip) |
| 89 | { |
| 90 | $data =~ s/(.)/$1 ^ 1/eg; |
| 91 | } |
| 92 | |
| 93 | # first just see if our data is in the stream |
| 94 | if ($data =~ /$search/) |
| 95 | { |
| 96 | print "Found $search in our stream ($data)\n"; |
| 97 | } |
| 98 | |
| 99 | # try removing parity every 4 and 8 bits |
| 100 | foreach my $parity (4, 8) |
| 101 | { |
| 102 | # try removing a parity bit every $parity bits |
| 103 | # test by cutting off a bit at a time in case we're in the wrong bit position |
| 104 | my $tmp = $data; |
| 105 | foreach (1 .. $parity) |
| 106 | { |
| 107 | my $test = $tmp; |
| 108 | $test =~ s/(.{$parity})./$1/g; |
| 109 | |
| 110 | if ($test =~ /$search/) |
| 111 | { |
| 112 | print "Found $search with parity every " . ($parity + 1) . "th bit, round $_ out of $parity ($test)\n"; |
| 113 | } |
| 114 | |
| 115 | # chop of a bit to change our bit position next round |
| 116 | $tmp =~ s/^.//; |
| 117 | } |
| 118 | } |
| 119 | } |