When I finally tried to hack together a the Okular digital signatures in Ubuntu, once updated, I found the documentation wanting. I recently switched to this LTS release - I wait longer than most to switch since I prefer KDE, and new releases often have a “growing pains” period for the environment. The Okular package in apt-get Ubuntu 22.04 LTS “Jammy Jellyfish” is the oldest release with the digital signatures enabled. Digital signatures have long been available to those using Adobe Acrobat for PDFs, but the ability to sign PDFs using free and open-source software (FOSS) is recent. Recently, I needed to sign and return some documents, but I realized that there was no simple documentation for how to use the new Okular digital signatures in Ubuntu. I do not know if any remote signing services allow you to hold the key, for example, on a 2-factor token device or encrypted on your own hard disk.Theory and Practice of Creating Okular Digital Signatures in Ubuntu You can sign more strongly with a cryptographic key - usually with the proviso that the remote signing service hold your key. You can sign weakly with an adopted picture of something that resembles your hand written signature - which is a very bad idea as noted by other answers and comments. You could also investigate remote signing services, where your PDF will be presented to you as HTML which you can then sign. The only way that a PDF can be signed using FOSS software is to wrap the PDF inside of an open digital signature file format. PDF is an open format but in this case Adobe have created their own extensions which are owned, patented and licensed by them in order to prevent others from being able to do this. The reason for this is that signable PDFs created with Adobe tools use Adobe proprietary extensions of the PDF format. There are no FOSS PDF readers that can sign an Adobe PDF. One is prompted to save the signed PDF under a new file name after that. A dialogue will ask for the private key to use, in case there are.Draw a rectangle where you want to have the visible hint for the."Digitally sign" icon in your preferred tool bar and click it. Click 'Digitally sign' in the 'Tools' menu.I hope that it will be possible to revert to an official version when signing support is released in my distribution's packages.Īfter successful installation, I could create a digital signature as advertised in the post: As typical for KDE, this "local" version of Okular does interfere with the official one from the distribution, which is partly changed to the new version even when starting the old binary (presumably this is due to KDE's system-wide registration of "parts" or some such component). The new version of Okular identifies as "Version 21.03.70". I have installed under /usr/local/ and created a start script okular-sign with the variable definitions as in the TU Dresden manual. I have completed the installation using the instructions in the script (watch out for truncated lines in the online-preview!) on KDE Neon 5.20 (based on Ubuntu 20.04 LTS) using Poppler as of Commit 407293bf and Okular as of Commit 110ccd61 (future versions should of course continue to work, so this is just for full reproducibility). Instructions and a build script are provided with the TU Dresden post. Note that this not about inserting a graphics with your scanned signature, but about adding a solid digital certification to the PDF, similar to what is supported by some Adobe products.Īs of December 2020, it is already possible to compile the current development version of Okular and the Poppler PDF library locally to obtain the feature. Details are found in a post by TU Dresden, who has sponsored the implementation of this feature. Okular (and Poppler) will support digital signatures in PDFs in its official release starting April 2021. Acrobat is, or at least used to be, a major offender in this regard-I have seen documents trivially "forged" because of this ill-conceived feature. It offers no security at all and in fact is detrimental to it: upon seeing your scribble on a document, recipients may be tempted to assume that it is authentic and not bother to check for an actual (and legally valid) electronic signature. png of my signature, and I basically want to insert it into the document on the dotted lineĪnyone having access to your PNG or any document where it is used, such as the PDF you are intending to embed this on, will have a perfect, infinitely reproducible copy of your autograph signature. To my knowledge, currently none of Okular's backends support electronic signatures, although that feature has been requested a number of times.Īs an alternative, a PDF (or any other file) may be signed using a detached signature with GPG or any of its numerous frontends (such as Kleopatra or Kgpg in KDE).
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |