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Preview can't digitally sign PDFs. I have to do this on a near daily basis. EDIT: I mean sign with a certificate, not add an image. Personally I would prefer t

Preview can't digitally sign PDFs. I have to do this on a near daily basis. EDIT: I mean sign with a certificate, not add an image. Personally I would prefer to not have any adobe software on my mac.

sqs 6y ago
By "digitally sign", do you mean insert a picture of your handwritten signature? It can do that: https://www.macrumors.com/how-to/digitally-sign-a-pdf-using-preview-on-mac/ https://www.macrumors.com/how-to/digitally-sign-a-pdf-using-.... If you mean cryptographically sign, then disregard my comment.
- freefriedrice 6y ago
  Yeah, the latter: keychain certificate (under "Certificates").
- hunter2_ 6y ago
  This lack of differentiation really grinds my gears. Why in the world do both of these activities share a name? It would be really interesting to take a random sample of the population and ask them some basic context like their occupation/education, and ask them whether a digital signature comprises a graphic of handwriting (validated with eyeballs) or something more sophisticated (validated with math). There will be some obvious trends, but I suspect there will also be some surprises.
  - saagarjha 6y ago
    The point of a signature is to affirm the authenticity of something. When you sign something by hand, you're showing that you reviewed it. If you cryptographically sign something, you're doing the same thing to a bunch of bits, and arguably in a way that's a less easy to forge.
  - freefriedrice 6y ago
    You're referring to "term overloading". This is pervasive throughout all domains of engineering, but more so in software because there are so many conflicting standards, definitions and citations. It's really hard to get a handle on. Like, I would assume that posting on HN the audience would assume I would not confuse "overlaying pixels of my signature on a document," with, say ECDSA sign & verify. But I was wrong to assume that. So, barring a common definition, should we speak with increased precision thus verbosity? Perhaps. But if THIS example grinds your gears, hooo boy, hang of for a ride.... :)
    - smichel17 6y ago
      To my own surprise, it was a pretty pleasant read and I didn't realize you were intentionally being over-verbose until "overlaying pixels".
darwingr 6y ago
Just dealt with this yesterday. It’s too bad because I really like the signatures I have saved under Preview. So I sign all signatures on a lease with Preview except for the very last one, which I did using a digital signature under Adobe Reader. it was a self-signed one certificate but the goal is still to have the other person feel comfortable with doing a contract over email than in person anyways.
monadic2 6y ago
What’s the benefit of signing the pdf itself rather than the distribution? If there’s a large need for this seems like an easy way to make a bit of money cutting out adobe.
toomuchtodo 6y ago
Could you use JSignPDF instead? https://github.com/kwart/jsignpdf https://github.com/kwart/jsignpdf

Preview can't digitally sign PDFs. I have to do this on a near daily basis. EDIT: I mean sign with a certificate, not add an image. Personally I would prefer to not have any adobe software on my mac.

sqs 6y ago

By "digitally sign", do you mean insert a picture of your handwritten signature? It can do that: https://www.macrumors.com/how-to/digitally-sign-a-pdf-using-preview-on-mac/ https://www.macrumors.com/how-to/digitally-sign-a-pdf-using-.... If you mean cryptographically sign, then disregard my comment.

freefriedrice 6y ago
Yeah, the latter: keychain certificate (under "Certificates").
hunter2_ 6y ago
This lack of differentiation really grinds my gears. Why in the world do both of these activities share a name? It would be really interesting to take a random sample of the population and ask them some basic context like their occupation/education, and ask them whether a digital signature comprises a graphic of handwriting (validated with eyeballs) or something more sophisticated (validated with math). There will be some obvious trends, but I suspect there will also be some surprises.
- saagarjha 6y ago
  The point of a signature is to affirm the authenticity of something. When you sign something by hand, you're showing that you reviewed it. If you cryptographically sign something, you're doing the same thing to a bunch of bits, and arguably in a way that's a less easy to forge.
- freefriedrice 6y ago
  You're referring to "term overloading". This is pervasive throughout all domains of engineering, but more so in software because there are so many conflicting standards, definitions and citations. It's really hard to get a handle on. Like, I would assume that posting on HN the audience would assume I would not confuse "overlaying pixels of my signature on a document," with, say ECDSA sign & verify. But I was wrong to assume that. So, barring a common definition, should we speak with increased precision thus verbosity? Perhaps. But if THIS example grinds your gears, hooo boy, hang of for a ride.... :)
  - smichel17 6y ago
    To my own surprise, it was a pretty pleasant read and I didn't realize you were intentionally being over-verbose until "overlaying pixels".

darwingr 6y ago

Just dealt with this yesterday. It’s too bad because I really like the signatures I have saved under Preview. So I sign all signatures on a lease with Preview except for the very last one, which I did using a digital signature under Adobe Reader. it was a self-signed one certificate but the goal is still to have the other person feel comfortable with doing a contract over email than in person anyways.

monadic2 6y ago

What’s the benefit of signing the pdf itself rather than the distribution? If there’s a large need for this seems like an easy way to make a bit of money cutting out adobe.

toomuchtodo 6y ago

Could you use JSignPDF instead? https://github.com/kwart/jsignpdf https://github.com/kwart/jsignpdf