Question about encrypted Private Keys

Hi all,

I am a newbie in this world on criptology, and I doubt if what I am
asking is not factible at all or just a dumb question. Nevertheless, I
hope you might find it interesting. Well, I shoot:

I have a bunch of certificates, which are in both formats, p12 and
..key. The owner have just told me that all of them are protected with
the same key. With openssl I decrypt the p12 sucessfully, and I get the
plain RSA key. The problem is, that one of the certificates do not have
a p12, only a .key. The .key is plain text and looks like

-----BEGIN RSA PRIVATE KEY-----
Proc-Type: 4,ENCRYPTED
DEK-Info: DES-EDE3-CBC,379AB79E55059F9A

gaakm48Y8qYA997fJREN4JtfVkfTdnVzaZK2 ....
----END RSA PRIVATE KEY-----

The problem is that I cannot decrypt with the password the user gave
me. I tried with all the .key files and the password seems invalid for
all of them. So, in my oppinion, there are different passwords for the
p12 files and for the key files. And here comes my question:

Is there any possibility to get the password of an encrypted private
key in the way showed above if we already know the key? How difficult
could that be to implement?

Thanks and Regards

Francisco

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