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Show HN: FalsiScan – Make it look like a PDF has been hand signed and scanned
- deleted 6y ago[deleted]
- ulucs 6y agoI love the idea. Is there any way to programmatically distort a digital signature so that I can avoid printing the signature pdf too?
- pedro596 6y agoVery nice, just wondering the security implications of having those nice PNGs stealed, someone can sign anything in your behalf... Adding some known pattern to the signature that can be recognized later in the print would be nice if you need to prove that it was not actually signed by you. But if you get to this point it is already a big mess...
- thatguyagain 6y agoNice example signature
- turbinerneiter 6y agoI don't get the magical power of a signature at all. Everybody can write my name under a document. This project basically allows you to forge your own signature. Is it still legally binding? Do these rules even remember the original intent?
- shinryuu 6y agoThe question is, can you forge your own signature? If both parties agree that the document is legally binding it seems a bit unlikely that the document would fall under the forged label. Though I am not a lawyer. It's also worth noting that digital signatures throughout the european union have legal status.
- toomuchtodo 6y agoDigital signatures also have legal status in the US. Until society catches up and uses cryptographic primitives provided by a national ID smart card (such that Estonia has) for authorizing intents, this is a satisfactory method to make document execution less painful. This project is already doing the easy part (“place pretty signature picture here”). Depending on your jurisdiction and their tolerance, you could also render a true crypto signature in ascii-armored format to assist in proving legitimacy (perhaps generated as a small print signature line under the signature). Sidenote: Some transactions require a "wet" signature (as in, actual ink on actual paper from an actual pen). This doesn't get around those transactions unfortunately.
- zo1 6y agoAll the more baffling why some countries are moving away from national identification and other digital signing initiatives to prove identity. E.g. the UK that introduced and then subsequently dismantled a national ID card and database (apparently it was a "privacy" issue for the government to have a record of citizens?). Imagine this, a first world country, living in the dark ages essentially when it comes to identity.
- toomuchtodo 6y agoIf you support national ID systems, please do your part to advocate for such systems whenever possible (as well as the necessary privacy and oversight controls). Progress is a function of effort. I'm working on the US side.
- 6y ago
- awirth 6y agoFrom this scripts, it looks like this doesn't convert to black and white, so this might work with Hanko (Japanese stamp seal) too?
- linschn 6y agoIf it doesn't, please do not hesitate to open an issue and I'll look into it :)
- mikehollinger 6y agoMac’s pdf viewer Preview has a signature capture feature built in that’s pretty slick. I use it all the time and haven’t encountered an objection. Tbh I’d wonder why you need to fuzz up and fake scan the image. If someone’s requiring that the doc be “signed in ink” or some such, more power to you!
- jonchang 6y agoFrom the link: "For bureaucratic reasons, a colleague of mine had to print, sign, scan and send by email a high number of pages. To save trees, ink, time, and to stick it to the bureaucrats, I wrote this script." So yes, it does seem like there are situations where a "digital" signature is insufficient.
- leesalminen 6y agoMy bank sometimes requires a “wet” signature and have rejected digitally signed PDFs from MacOS Preview before. This tool will come in handy.
- cgrand-net 6y agoMy bank used to reject scans but accept faxes... bureaucratic reasons.
- dd36 6y agoFaxes are considered secure.
- lima 6y agoIt's not a false signature, this kind of thing is standard practice for digitally signing documents. DocuSign even allows you to insert a computer-generated signature that looks nothing like your "real" one. What matters is the audit trail. This is legally binding the same way clicking the "Buy" button on Amazon is.
- sbarre 6y agoYes yes that's all nice and good until the person you're signing the document for tell you "I don't care what someone on Hacker News thinks is good enough, I need this signed in ink". I've encountered this before myself, and so have many other people, and we're all already aware of what you're saying.
- xnyan 6y agoCan I have your phone number, I need you to explain this to my HR department and to the HR department at my last job and of my roofing contractor and dozens of other people who demand wet ink signatures.
- popotamonga 6y agoWhy is this a thing? Why not sign it with a proper digital certificate? In my country we can sign documents with our id card.
- ceejayoz 6y agoThe USA doesn't have a national ID card.
- bagacrap 6y agoPassport
- tecleandor 6y agoNot everybody has a passport. A Passport costs more than a hundred dollars. Not everybody is eligible to a passport. For having a passport you need nationality, and you need to be able to have contracts with non national persons.
- PeterisP 6y agoYour comment about nationality seems interesting - it's a fundamental human right to have nationality (https://www.ohchr.org/EN/Issues/Pages/Nationality.aspx); https://www.ohchr.org/EN/Issues/Pages/Nationality.aspx); what do you mean by "non national persons" ? The common mass cases e.g. illegal immigrants are not non-national persons, they're just nationals of some other country. There are certain edge cases that result in stateless people, but the general solution for that is for states to work to assign nationality, it's definitely reasonable in many countries to not be able to have standard contracts with such people until they get their identity documents issued.
- tecleandor 6y agoI might live in in a country I'm not a national, so I don't have a local passport. Illegals often cross borders without papers, so they don't have any passports to sign anything. Sorry I'm brief, but I'm super busy today :P
- giancarlostoro 6y ago(HBO) Silicon Valley Reference: That looks like the Gavin Belson signature. This is kind of useful though, I was in shock and horror when I realized one PDF my Adobe Fill & Sign app couldnt... fill and sign, an actual IRS tax form. I don't know why they let you fill most of it out but force you to sign the damn thing. What's even more confusing is other forms don't restrict this, it's just one of the ones I tried (can't remember which one but it was a while ago).
- saagarjha 6y agoI think there's a much less niche thing it might be referencing.
- hwc 6y agoI just printed the pages I needed to sign, signed them, scanned them, and then stitched them into the original PDF.
- arkanciscan 6y agoIs anyone aware of an actual court case where the validity of a DocuSign doc was held up?
- ceejayoz 6y agoI doubt there are any that hinge on that. I strongly suspect there are many thousands of cases in which a contract that was signed via them was simply treated as legitimate by both parties, though.
- tathougies 6y agoDocuSign is valid by statute: https://en.wikipedia.org/wiki/Electronic_Signatures_in_Global_and_National_Commerce_Act https://en.wikipedia.org/wiki/Electronic_Signatures_in_Globa... Their security implementation or the authenticity mechanism they have for recording is not even really up for scrutiny, so long as they can provide some kind of proof that the signing occurred and that the counterparty signed with an understanding that the electronic signature was the same as a real signature.
- ornornor 6y agoThe Preview app that lets you very easily sign PDFs is a piece of software I very dearly miss on Linux. There are solutions on Linux but none as smooth and universal as Preview.
- danbenoni 6y agoPretty dope.
- TehShrike 6y agoThe shell scripts depend on a "convert" cli command – that command doesn't exist on my machine, and I can't find any reference to it in the documentation, does anyone know where that command comes from?
- jammmety 6y agoconvert is part of imagemagick: https://imagemagick.org https://imagemagick.org
- lovasoa 6y agoThis comes from imagemagick. https://imagemagick.org/script/convert.php https://imagemagick.org/script/convert.php
- turdnagel 6y agoConvert is an alias to "magick convert" which is a command built into ImageMagick. Installing ImageMagick is pretty easy, usually just `[packagemanager] install imagemagick`
- deleted 6y ago[deleted]
- linschn 6y agoI'll add installation instructions to the Readme tomorrow, thanks for pointing that out.
- ebencooke 6y agoQuestions about the reproducibility of signatures reminds me of this case https://en.wikipedia.org/wiki/Howland_will_forgery_trial https://en.wikipedia.org/wiki/Howland_will_forgery_trial in which Charles and Benjamin Pierce were brought in as expert witnesses. There's a good account in https://en.wikipedia.org/wiki/The_Metaphysical_Club:_A_Story_of_Ideas_in_America https://en.wikipedia.org/wiki/The_Metaphysical_Club:_A_Story....
- endergen 6y agoWell, this is the greatest open source project ever. Time to close for the reason, internet.
- ocdtrekkie 6y agokentonv was looking for something like this late last year! https://twitter.com/KentonVarda/status/1199022850369146880 https://twitter.com/KentonVarda/status/1199022850369146880
- aclimatt 6y agoHa! My co-worker made one of these for the same reason. Some places still require "wet" signatures, and some people (us) like to stick it to bureaucracy and prove that they can't tell the difference. For a one-liner, if you use any tool to generate a realistic version of your signature, or do what I do and actually scan a version of your signature once, and then have that as a PNG that you can drop on any PDF of your liking, here's a line to make it look nice and "scanned": convert "$1" -alpha Off -density 150 -colorspace gray -blur 0.5x0.5 -rotate 0.4 -level 40%,60% "scanned-$1" Or for even more noise and poor quality: convert "$1" -colorspace gray \( +clone -blur 0x1 \) +swap -compose divide -composite -linear-stretch 5%x0% -rotate 1.5 scanned-$1.pdf
- tareqak 6y agoIs that an invocation of the `convert` tool from ImageMagick?
- aclimatt 6y agoYep, it just uses ImageMagick's `convert` to take the PDF, rotate it a little bit, blur the text, and generally reduce the quality just like a scan would. The OP also uses a few other flags like `+noise Gaussian` and `-attenuate 0.25` which you could toss in. Same concept, just wanted to share a one-liner you can use if you already have a PDF with a signature on it, and you need that nice "scanned" look.
- dror 6y agoOr just use Libreoffice and insert the image in the right place. Has worked for years.
- peteretep 6y agoThis is cool, although after playing with it and a bit and doing some Googling, I like: https://gist.github.com/andyrbell/25c8632e15d17c83a54602f6acde2724 https://gist.github.com/andyrbell/25c8632e15d17c83a54602f6ac...
- mkchoi212 6y agoImmigration documents often need to be hand signed and scanned. This looks cool and everything but not sure if I'd risk getting an immigration application rejected :p Will try on other less official stuff though ha
- pingec 6y agoThis is great, thanks for sharing! Does it support multipage pdf documents and doing multiple signatures per document? Related to this, perhaps a UI for marking all the spots where signatures are required would make this tool extremely powerful!
- linschn 6y agoThanks, It does support multiple page, it will add a randomly chosen signature at the same place every page. The ui is going to be a lot more complicated to code. Maybe I'll give it a try someday.
- zelly 6y agoI have to do this quite often. I end up using a scanned image of my signature with Gaussian noise added in Photoshop. You can add Gaussian monocromatic noise to the whole page (and rotate it slightly, for good measure) to make it look like you killed a tree.
- spapas82 6y agoIn my organization we have a different problem. We heavily use signed pdf files for all our internal documents - if a document is not signed it's not valid (they are mainly signed with JSignPdf). A number of internal applications need such signed files in order to proceed with a workflow. Checking if a PDF file has been digitally signed, how many signatures are there and if the signatures are all valid is not an easy task! Actually, I only know how to do it in java using bounty castle. To help non-java apps with this I've implemented a small java application that provides a REST (and form) api for uploading a signed PDF file and returning information about the signatures. It works in my organization for more than 3 years and it's has saved us from hundreds of erroneously signed PDF files! I've open sourced it for anybody having similar requirements: https://github.com/spapas/pdf-sign-check https://github.com/spapas/pdf-sign-check.
- DeathArrow 6y agoI could use a mobile app to do that. In my country, to leave your home to do shopping in this period, you are required by military ordnance to fill a form stating the reason of leaving your home. You can show it on your mobile phone, but you have to print it, sign by hand and take a picture of it.
- mr_toad 6y agoWhat if you don’t have a working printer at home? Do they just let you starve?
- DeathArrow 6y agoYou can write the thing by hand.
- kotutku 6y agoNeat! I've been doing this manually by adding my signature in GIMP and taking a photo of my laptop screen.
- davchana 6y agoThis is at least one place where JPG compression helps. In PDF Xchange, I drop in my scanned clear signature (a font), then merge & pdf print the page as 50% jpg quality.
- ronyfadel 6y agoThis is cool! Now someone make an app out of this please :)
- jimothyhalpert7 6y agoHas anyone had any experience trying to prove the authenticity of a signature? I remember reading somewhere that there are only three universities in the world, that have a department specializing in detecting signature forgery.
- deleted 6y ago[deleted]
- xenonite 6y agoDid you note that the example signature is a phallicism? More of these in "Signature_example.pdf". In my opinion, this is a bit childish. But on the other hand, the whole scan-and-sign procedure is also a bit childish if you ask me.
- MaxBarraclough 6y agoInteresting idea, but to me, the output just doesn't look like a scanned document.
- cs02rm0 6y agoFor bureaucratic reasons... I feel that pain. When your only tool is bureaucracy everything looks like a nail. Or something like that. I once had what I think was a document for a mortgage application refused because I'd printed it, signed it and took a photo on my phone to email back. Apparently it had to be done with a scanner and a camera was unacceptable. I didn't have a scanner, so I chanced my arm, desaturated and thresholded the image then resubmitted it. I was thanked and it was accepted.
- entelarust 6y agoTIL about the WTFPL license ;) http://www.wtfpl.net/about/ http://www.wtfpl.net/about/
- A4ET8a8uTh0 6y agoIt would not work for us, but I appreciate the spirit of trying to save trees from pointless markings. Love it.
- bambax 6y agoI usually do the same thing, manually. I have a set of about 10 signatures that I vectorized (so that they scale with no visible artifacts). I apply one of those signatures to the PDF documents in an editor that can edit PDFs (currently using Affinity Designer or Publisher, they're excellent). Then I take pride in outputting the cleaniest PDF possible. Never received any complaint. Most people on the receiving end probably print them out, and they appreciate the clean result, compared to what you get when you re-scan it (or intentionally blur it). That said, for 27 pages (!!) that tool would prove a lifesaver.
- stevespang 6y agoDoes this get past DocuSign security measures ? (I am assuming that Docusign timestamps and also ip address stamps . . . .)
- globular-toast 6y agoLast time I had to do this was for a two page document which required a signature on the second page. Even though I thought it was silly, I did sign the second page in ink and scanned it. It was rejected because I didn't also scan the first page despite it requiring no changes. At that point I just concatenated the original first page to my initial signed scan and sent it back and it was all fine. Ridiculous. One thing I did think about, though, is the legal aspect. Fraud is a serious crime and I wonder if such a thing, however silly, might just be considered fraud. In that case it might not be worth fighting the bureaucracy.
- forinti 6y agoFinancial department wanted me to turn in a signed document after lockdown. I have an HP 3 in 1 but it no longer prints. So I scanned my signature, extracted it with gimp, and added it to the document. The result was excellent.
- rolandog 6y agoI was thinking of doing something like this the day before yesterday! I love your implementation! Extremely useful. I actually wrote about the laborious effort to create a pseudo 'false document' by manually using Gimp on my blog; I wrote a very naive back-of-a-napkin pseudo algorithm... I was actually thinking about learning Gimp's Script-Fu to generate the signature with the Ink Tool.