4 ms·

> If you're in the "whistle-blowers, activists, spies" category, is the airgap (physically) really required or would a smart card give you the same protection?

> If you're in the "whistle-blowers, activists, spies" category, is the airgap (physically) really required or would a smart card give you the same protection? Smartcard doesn't protect you if your Internet facing machine is compromised. With a separate air gapped machine, you could print out the cipher text from the Internet connected machine, then scan it in/OCR it into the non-Internet connected machine and decrypt it there. Then you could encrypt a response on the non-Internet connected machine, read the cipher text back in to the Internet connected machine via scanning+OCR and send it out.

TheLoneWolfling 12y ago
...Assuming your input stack on your non-internet connected machine is uncompromisable. In practice, this is decidedly not the case. OCR is complex. Your attack surface is not exactly tiny.
- a1369209993 12y ago
  Good OCR is complex. "Here's a jpeg with 80 lines of 80 characters (from a set of 64 ascii characters chosen for maximum descernability); do your best and I'll run that through a ECC that cuts down to a 32KB chunk." is rather less so. Also, there's no reason your OCR program needs any permissions other than reading a single jpeg and writing a single text file.
  - TheLoneWolfling 12y ago
    You can make the same argument about a non-airgapped computer, though. I don't see any advantage of this over (say) it connected via a dead-simple serial connection.
- pgeorgi 12y ago
  For computer <-> computer communication, you don't need to print in plain text. Print things as barcodes (or qr or whatever you fancy), then scan them over there - those are much easier and more reliable to parse.
darklajid 12y ago
Thanks. My fault. You answered my question, but I asked the wrong one in the first place. Given this sentence in the article: >An "air gap" is a low-tech, widely understood method of protecting secret key material from being compromised. If we send PGP/MIME formatted mail, air-gapping becomes inconvenient to the point of being infeasible. my question was: Wouldn't a smart card - prevent the compromise of one's secret key - therefor allow sending PGP/MIME stuff again quite easily? (your airgap explanation made sense of course)

TheLoneWolfling 12y ago

...Assuming your input stack on your non-internet connected machine is uncompromisable. In practice, this is decidedly not the case. OCR is complex. Your attack surface is not exactly tiny.

a1369209993 12y ago
Good OCR is complex. "Here's a jpeg with 80 lines of 80 characters (from a set of 64 ascii characters chosen for maximum descernability); do your best and I'll run that through a ECC that cuts down to a 32KB chunk." is rather less so. Also, there's no reason your OCR program needs any permissions other than reading a single jpeg and writing a single text file.
- TheLoneWolfling 12y ago
  You can make the same argument about a non-airgapped computer, though. I don't see any advantage of this over (say) it connected via a dead-simple serial connection.
pgeorgi 12y ago
For computer <-> computer communication, you don't need to print in plain text. Print things as barcodes (or qr or whatever you fancy), then scan them over there - those are much easier and more reliable to parse.

darklajid 12y ago

Thanks. My fault. You answered my question, but I asked the wrong one in the first place. Given this sentence in the article: >An "air gap" is a low-tech, widely understood method of protecting secret key material from being compromised. If we send PGP/MIME formatted mail, air-gapping becomes inconvenient to the point of being infeasible. my question was: Wouldn't a smart card - prevent the compromise of one's secret key - therefor allow sending PGP/MIME stuff again quite easily? (your airgap explanation made sense of course)