81 lines
1.7 KiB
Perl
Executable file
81 lines
1.7 KiB
Perl
Executable file
#!/usr/bin/perl
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=encoding utf8
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=head1 NAME
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goodpasswd - generate good access codes
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=head1 SYNOPSIS
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B<goodpasswd>
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=head1 DESCRIPTION
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B<goodpasswd> generates access codes that:
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=over 3
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=item Z<>* are hard to guess
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=item Z<>* will be displayed unambigously in any (normal) font
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=item Z<>* will survive being passed through a bad fax machine
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=item Z<>* will survive being passed through handwriting
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=item Z<>* will survive unquoted in most scripts
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=item Z<>* has characters from the character classes UPPER lower number and sign
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=back
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=head2 Characters considered too close
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These character couples are too similar either in different fonts or
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in a bad copy and are thus forbidden:
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B8 cC g9 G6 kK lI l1 oO O0 pP sS S5 uU vV xX zZ Z2 ,. :; `'
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These characters cause problems in URLs: @/:
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These characters cause problems in shell: ! " # $ & ( ) [ ] { } ? | < > \ * =
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These characters cause problems in SQL: % (wildcard) + (login)
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These characters are hard to type: ^ ~ ¨ ¤ § ½ æ ø å Æ Ø Å
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=head2 Other restrictions
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Never use the same chars twice in a row: e.g. -- is bad.
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Do not start with '-' as that looks like an (long) option
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=head1 EXAMPLE
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B<goodpasswd> will give output similar to iTtNRf3MYdMb+rNhYniY.
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=cut
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# US-kbd: ~!@#$%^&*()_+ [] {} ;'\ :"| < > ,./ <>?
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# DK-kbd: §!"#¤%&/()=?` å" Å^ æø' ÆØ* < > ,.- ;:_
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# Common: ! # % < > ,.
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my $pw;
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# 31-1 possibilities = ~4.9 bit entropy
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# 20 chars = 98 bit
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my @chars=split //, 'abdefhijmnqrtyADEFHJLMNQRTY347-';
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do {
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$pw = "";
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for (1..20) {
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$pw .= $chars[rand $#chars+1]
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}
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} while (($pw =~ /^[+-]/ or $pw =~ /(.)\1/) or
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not($pw =~ /[A-Z]/ and
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$pw =~ /[a-z]/ and
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$pw =~ /[0-9]/ and
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$pw =~ /[^a-zA-Z0-9]/));
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print "$pw\n";
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