Recover passwords from PDFs

Many of us, for various reasons, password different types of documents or files, but many of us also forget it.

In the case of PDFs there is an application in Debian (and I assume in the rest of the distributions) called pdf crack and it is a command line utility. To install it we execute in console:

sudo aptitude install pdfcrack

To use it, we just have to indicate the option -f and the name of the pdf file whose password we have forgotten, like this:

pdfcrack -f archivo_pdf_con_clave.pdf

This method is still effective, but it loads the processor a lot, so it is advisable to use some of the options that the application brings, which are:

--charset=CHARSET Tries all combinations of the characters indicated in CHARSET.

--maxpw=INTEGER The maximum length for keys is INTEGER.

--minpw=INTEGER The minimum length for keys is INTEGER.

--wordlist=FILE Use the file FILE as a dictionary of words to test.