md5 - PHP

Greger

Hi all,
Im quite comfortable with php but new to encryption, could someone please
highlight when encryption would be a good thing.

Also:is there a reverse of the md5 function? ( in other words in what way is
md5 ( + the others sha...)used?
--
http://www.gregerhaga.net

Aug 18 '05 #1

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1807

Marcin Dobrucki

Greger wrote:

Im quite comfortable with php but new to encryption, could someone please
highlight when encryption would be a good thing.
When you have a secret to protect?
Also:is there a reverse of the md5 function? ( in other words in what way is
md5 ( + the others sha...)used?

Ehh... no. MD5 is a one-way hash (http://en.wikipedia.org/wiki/MD5).
You really ought to have a look at some literature, maybe start here:
http://www.sans.org/rr/

/Marcin

Aug 18 '05 #2

Alvaro G Vicario

*** Greger wrote/escribió (Thu, 18 Aug 2005 14:21:42 +0200):

Im quite comfortable with php but new to encryption, could someone please
highlight when encryption would be a good thing.

Also:is there a reverse of the md5 function? ( in other words in what way is
md5 ( + the others sha...)used?

MD5 is a hash that's normally displayed as a 32 character string. That
means that even the MD5 hash of a 2GB files is 32 byte long: if it was
reversable we would have found the most amazing compression algorithm ;-)

Encryption can be rather complicate. I suggest you first define your needs
and then find solutions for them.

Hashes have several usages:

* Test file integrity
* Password storage (you cannot decrypt passwords, yet you can encrypt the
value provided by user and compare)

--
-- Álvaro G. Vicario - Burgos, Spain
-- http://bits.demogracia.com - Mi sitio sobre programación web
-- Don't e-mail me your questions, post them to the group
--

Aug 18 '05 #3

zen

Why not use something like:
http://www.sourceguardian.com/
This will encrypt the php source

regards
nik
http://www.ads4links.com

"Alvaro G Vicario" <al************ ******@telecomp uter.com> wrote in message
news:13******** *************** *******@40tude. net...

*** Greger wrote/escribió (Thu, 18 Aug 2005 14:21:42 +0200):
Im quite comfortable with php but new to encryption, could someone please highlight when encryption would be a good thing.

Also:is there a reverse of the md5 function? ( in other words in what way is md5 ( + the others sha...)used?

MD5 is a hash that's normally displayed as a 32 character string. That
means that even the MD5 hash of a 2GB files is 32 byte long: if it was
reversable we would have found the most amazing compression algorithm ;-)

Encryption can be rather complicate. I suggest you first define your needs
and then find solutions for them.

Hashes have several usages:

* Test file integrity
* Password storage (you cannot decrypt passwords, yet you can encrypt the
value provided by user and compare)

--
-- Álvaro G. Vicario - Burgos, Spain
-- http://bits.demogracia.com - Mi sitio sobre programación web
-- Don't e-mail me your questions, post them to the group
--

Aug 18 '05 #4

Dimitry Rybkin

No one is talking about ecrypting the php source here...

The question was: how does one ecrypt data... not their source files.
zen wrote:

Why not use something like:
http://www.sourceguardian.com/
This will encrypt the php source

regards
nik
http://www.ads4links.com

"Alvaro G Vicario" <al************ ******@telecomp uter.com> wrote in message
news:13******** *************** *******@40tude. net...
*** Greger wrote/escribió (Thu, 18 Aug 2005 14:21:42 +0200):
Im quite comfortable with php but new to encryption, could someone
please
highlight when encryption would be a good thing.

Also:is there a reverse of the md5 function? ( in other words in what
way is
md5 ( + the others sha...)used?

MD5 is a hash that's normally displayed as a 32 character string. That
means that even the MD5 hash of a 2GB files is 32 byte long: if it was
reversable we would have found the most amazing compression algorithm ;-)

Encryption can be rather complicate. I suggest you first define your needs
and then find solutions for them.

Hashes have several usages:

* Test file integrity
* Password storage (you cannot decrypt passwords, yet you can encrypt the
value provided by user and compare)

--
-- Álvaro G. Vicario - Burgos, Spain
-- http://bits.demogracia.com - Mi sitio sobre programación web
-- Don't e-mail me your questions, post them to the group
--

Aug 18 '05 #5

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