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Commit | Line | Data |
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14ac2f1e | 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 | } |