MD5 encrypted password

shilpam has asked for the wisdom of the Perl Monks concerning the following question:

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Re: MD5 encrypted password by broquaint (Abbot) on Jul 02, 2004 at 07:20 UTC
The `Digest::MD5` module is not an encryption module but is for creating 'fingerprints' of data. For two-way encryption something like `Crypt::RC4` will do the trick e.g `use Crypt::RC4; my $enc_pw = RC4(seekrit => 'johnr'); my $dec_pw = RC4(seekrit => $enc_pw); print 'enc_pw = ', unpack( 'H*' => $enc_pw ), "\n"; print 'dec_pw = ', $dec_pw, "\n"; __output__ enc_pw = 344eedff3d dec_pw = johnr` [download] HTH `_________ broquaint`	[reply] [d/l]
Re: MD5 encrypted password by beable (Friar) on Jul 02, 2004 at 07:14 UTC
Sorry! MD5 is one-way. You can encrypt your password, but you can't decrypt it. What you can do, is ask the user what they think the password is, encrypt it, and see if it's the same as the previous encrypted password you got. If the newly encrypted password is the same as the previously encrypted password, they got it right. Otherwise, they got it wrong.	[reply]
Re: MD5 encrypted password by tachyon (Chancellor) on Jul 02, 2004 at 09:20 UTC
No. MD5 is not a cipher it is a hashing function ie it takes and arbitrary input string and turns it into a (almost guaranteed to be unique) 128 bit digest. It is designed to be one way ie string->hash. It is not possible to do hash->string. If you want to be able to retrieve passwords but store them in an encrypted state you need a cipher. Crypt::Blowfish with Crypt::CBC is my weapon of choice but there are lots of options. cheers tachyon	[reply]
Re: MD5 encrypted password by wufnik (Friar) on Jul 02, 2004 at 13:31 UTC
if you do find a way of reversing md5 do let me know. don't tell anyone else either ;-) ...wufnik -- in the world of the mules there are no rules --	[reply]
Re^2: MD5 encrypted password by tachyon (Chancellor) on Jul 03, 2004 at 05:55 UTC
It would make a wonderful compression algorithm, imagine ;-) `my $md5 = md5($complete_works_of_shakespere); # compress to 128 bits my $plays = reverse_md5($md5); # inflate 128 bits into +~ 1 M bit. print $plays; # torture new generation + of english students` [download] It is along the lines of loaves and fishes to strech those bits so far.... cheers tachyon	[reply] [d/l]