I recently needed to sign a pdf document for legal purposes. The other party was willing to accept a digital signature. That does not mean copying an picture onto a pdf document. It's using public key crypto to sign the pdf document. Acrobat can do it, but I use free software, so, after about 30 minutes I figured out how to do it.
- I extracted my csail certificate from my browser. In firefox
- edit->preferences->advanced->encryption->view certificates
- select the certificate
- then hit backup
- save it as a pkcs12 file
- you'll be asked for a password for the backup. You'll use this later.
- I got jsignpdf-1.3.0 and installed it
- $ unzip JSignPdf-1.3.0.zip
- $ cd jsignpdf-1.3.0
- I ran it: $ java -jar JSignPdf.jar
- A simple window popped up with some forms to fill in.
- keystore type: PKCS12
- keystore file: choose the backup made of the certificate
- keystore password: the password you used
- input file: the pdf file to sign
- output file: I chose another name to avoid overwriting something useful
- I clicked the checkbox on "visible signature"
- Went to the "settings" box next to 'visible signature"
- I chose the page where the signature needed to be placed, and I chose coordinates. I found the coordinates by running gv input.pdf since ghostview shows the coordinates in the upper left corner. For example, I put my signature on page 7 and put signature at coordinates
- 147
- 482
- 369
- 519
- I chose Display: "Signature name and decsription"
- Hit "close"
- Then "sign it" on the original jpdfsign window.
- A simple window popped up with some forms to fill in.
