To unlock a pdf with a password, note that there are 2 general types of software for this: 1. one simply removes the password 2. recovers the password. For softwares that simply removes the password, you must be able to open the pdf and all you want to do is just to be able to remove the password that locks various rights to manipulate the document, such as copying, underlining, etc. For PDF that needs a password before you can even open it, there is no other recourse than to use the 2nd type of software that will recover the password. While the first one, which is just to remove the password, can work with lightning speed, the 2nd type, if you have no hint of what the password is, can take months, or even years, and for my slow computer, maybe centuries--so I'll leave the computer on and leave the answer as an inheritance for my grandsons.

There are at least 2 brands of such software given in the past, this being the third. If anybody is going to use this to recover a password (to open a pdf), he must have a pretty clear idea of what the password is composed of, to make adequate choices for the search criteria. It also means that it is only useful for cracking your own forgotten password. Try cracking such password as @#b(*?/?^*gUh*9)-)*jKh%5&*(#!@/>/.Oik-=-ojuiyu4, and see if it will never take you years at least.

This said, the usefulness of such software is really very limited. How many of us will frequently lock our pdf from opening, and at the same time, frequently forget the password?

But WAIT!! We now have CPU with 4 cores, maybe latter with 8 cores, 100 cores, then, maybe, this type of software might be useful in hacking on other people passwords, but then by that time, higher level of encryptation may compete with it.

Andrew  –  16 years ago  –  このコメントは役に立ちましたか？ はい | いいえ (+74)

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The Good
* Fairly straightforward.
* Ability to limit the scope of the brute-force attack if user has any idea of how long and what type of characters define the password.
* Can recover the owner and user passwords.
* Can perma-decrypt and/or remove any digital signatures.
* Users can pause the password recovery and resume from where it was stopped at will.
* Multiple instances can be run of the program so users can recovery passwords from multiple PDFs at once.
* Has a "history" which logs all broken passwords for future reference.

The Bad
* Relies solely on brute force.

For final verdict, recommendations, and full review please click here.

Ashraf  –  16 years ago  –  このコメントは役に立ちましたか？ はい | いいえ (+60)

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@shades:
Actually your activation key was sent to you right after requesting it.

If you don't receive it, please make sure that your e-mail filter doesn't block messages (or puts them into spam folder) from "support_at_eltima.com".

Or provide any alternative e-mail address while requesting activation key to which it would be possible to send your activation key once again.

Eltima Software  –  16 years ago  –  このコメントは役に立ちましたか？ はい | いいえ (+17)

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@SilenceIsGolden: "I am a freelancer and send out my invoices as password protected PDFs. I’d sure hate it if it were that easy to crack my protection."

Oh yes it is. There are many programs that can easily defeat the wimpy security that a PDF password provides.

Your best bet, if you want to prove that a document has not been tampered with, is to digitally sign it with a third-party strong encryption package, such as GnuPG. Provide the signature file along wit the PDF file (and keep it yourself, too), and you can prove in a court of law that the document has (or has not) been modified since you signed it.

HTH

Sue D. Nymme  –  16 years ago  –  このコメントは役に立ちましたか？ はい | いいえ (+16)

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Hello carrotmuncher. Try to type the code instead of pasting it. It worked for me.

consuella  –  16 years ago  –  このコメントは役に立ちましたか？ はい | いいえ (+11)

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