Created
July 8, 2011 12:12
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Using bcrypt to secure passwords in a Perl application
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#!/usr/bin/perl | |
use Crypt::Eksblowfish::Bcrypt; | |
use Crypt::Random; | |
$password = 'bigtest'; | |
$encrypted = encrypt_password($password); | |
print "$password is encrypted as $encrypted\n"; | |
print "Yes the password is $password\n" if check_password($password, $encrypted); | |
print "No the password is not smalltest\n" if !check_password('smalltest', $encrypted); | |
# Encrypt a password | |
sub encrypt_password { | |
my $password = shift; | |
# Generate a salt if one is not passed | |
my $salt = shift || salt(); | |
# Set the cost to 8 and append a NUL | |
my $settings = '$2a$08$'.$salt; | |
# Encrypt it | |
return Crypt::Eksblowfish::Bcrypt::bcrypt($password, $settings); | |
} | |
# Check if the passwords match | |
sub check_password { | |
my ($plain_password, $hashed_password) = @_; | |
# Regex to extract the salt | |
if ($hashed_password =~ m!^\$2a\$\d{2}\$([A-Za-z0-9+\\.]{22})!) { | |
# Use a letter by letter match rather than a complete string match to avoid timing attacks | |
my $match = encrypt_password($plain_password, $1); | |
my $bad = 0; | |
for (my $n=0; $n < length $match; $n++) { | |
$bad++ if substr($match, $n, 1) ne substr($hashed_password, $n, 1); | |
} | |
return $bad == 0; | |
} else { | |
return 0; | |
} | |
} | |
# Return a random salt | |
sub salt { | |
return Crypt::Eksblowfish::Bcrypt::en_base64(Crypt::Random::makerandom_octet(Length=>16)); | |
} |
It might be better to use Crypt::Random for salt generation:
sub salt {
return Crypt::Eksblowfish::Bcrypt::en_base64(Crypt::Random::makerandom_octet(Length=>16));
}
Turning an octet binary string into base64 adds 1/3 the length of the binary string, so this works better yet in the above gist, no additional $salt=substr($salt,0,16), on a 22 character base64 string that I was getting, will be required:
sub salt
{
return Crypt::Eksblowfish::Bcrypt::en_base64(Crypt::Random::makerandom_octet(Length=>12));
}
PS Thank you both, this was what i was looking for to avoid sending plaintext pw to database to compare to hashed pw there. Much better.
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The salt can have a forward slash, so your regexp on line 31 should be,