PHP: How to retrieve original value from hashed / encrypted email address

Asked Jul 11 '15 at 13:45

Active Jul 11 '15 at 13:45

Viewed 277 times

I am new to PHP and hope someone can help me with this.

I use PHP to hash / encrypt an email address as follows:

$email = "someEmail@someProvider.com";
$emailHashed = password_hash($email, PASSWORD_BCRYPT);

This works as intended and creates a string with 60 characters.

Can someone tell me how I can retrieve the email from this or what is the reverse way to get the original unhashed and unencrypted email from $emailHashed ?

I couldn't find a way to fix this myself.

Many thanks in advance.

asked Jul 11 '15 at 13:45

TaneMahuta

4

You can't. Hashes are *one way*. You shouldn't be hashing email addresses. – John Conde Jul 11 '15 at 13:46
Thanks. Even if the hash was created on my computer ? – TaneMahuta Jul 11 '15 at 13:47
1

see http://stackoverflow.com/questions/24024702/how-can-i-decrypt-a-password-hash-in-php – kamal pal Jul 11 '15 at 13:47
Since this is only about emails (not passwords) is there another way of encryption in PHP that I could use here and that would allow me to retrieve the original value ? – TaneMahuta Jul 11 '15 at 13:48
It doesn't matter where it was created. – John Conde Jul 11 '15 at 13:48
5

Can I get the cow back from the beefburger? Even if the beefburger was created on my own farm? – Mark Baker Jul 11 '15 at 13:48
2

[Here's how to do two way encryption with PHP](http://stackoverflow.com/questions/2448256/encrypting-decrypting-file-with-mcrypt/2448441#2448441) – John Conde Jul 11 '15 at 13:49
@MarkBaker: Good explanation - thanks. :) Just added a comment above (and getting hungry now). – TaneMahuta Jul 11 '15 at 13:49
For encryption, you can use [mcrypt](http://php.net/manual/en/book.mcrypt.php) – Mark Baker Jul 11 '15 at 13:49
@MarkBaker: Thanks - if I use mcrypt for the email how can I retrieve it back then ? – TaneMahuta Jul 11 '15 at 13:50
@JohnConde: Thanks for this - that's very interesting ! – TaneMahuta Jul 11 '15 at 13:51
mcrypt has a [decrypt](http://php.net/manual/en/function.mcrypt-decrypt.php) function – Mark Baker Jul 11 '15 at 13:51
@JohnConde I'd recommend [this instead](http://stackoverflow.com/questions/9262109/php-simplest-two-way-encryption/30189841#30189841). – Scott Arciszewski Jul 15 '15 at 04:28

PHP: How to retrieve original value from hashed / encrypted email address

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