Just 128 bits? I expect punch cards to hold 80 columns of 12 bits :-)
Show HN: PunchCard Key Backup
11–20 of 51 posts
Re: Show HN: PunchCard Key Backup
#12There really should just be some ui for quickly typing out the stream of 1s and 0s row by row instead of clicking checkboxes.
Re: Show HN: PunchCard Key Backup
#13I love this so much. This, this right here is why I still visit Hacker News. I'm going to use this today and pave a path to my CNC router to make it stupidly easy to generate these plates on-demand.
Thus defeating the entire purpose! Unless you plan to wipe your router's firmware after every one.
Re: Show HN: PunchCard Key Backup
#14There really should just be some ui for quickly typing out the stream of 1s and 0s row by row instead of clicking checkboxes.
There is:
* press `reset` (to clear the checkboxes);
* press `tab` (to select the first checkbox);
* if the current bit is `1` (i.e. there is a hole in the pattern), press `space`;
* move to step 2 (i.e. press `tab`);
Re: Show HN: PunchCard Key Backup
#15Just 128 bits? I expect punch cards to hold 80 columns of 12 bits :-)
This is how much I could pack on a standard (CR80 ID) card sized plate, while still being able to punch the holes without power (or precision) tools. (The aspect of ease of creation with household items was paramount for my design.)
There is also the problem of long term durability. Not being a construction engineer, or metallurgist, I have no idea what is considered "survivable" in case of an unlikely accident (such as fire, flood, crash, etc.), especially if one uses aluminium as the material. The more holes, the smaller the holes, I think the less likely chance they wouldn't degrade easily if not treated with care. (Aluminium is cheap, easy to work with just a cutter, screwdriver, and ruler.)
Moreover, 128 bits is plenty enough for encryption purposes. The AES standard uses key sizes of 128, 192 and 256 bits, but at the moment even the 128 bit keys provide plenty enough security.
Thus, if one needs to store more than 128 bits, one could just use a standard encryption tool like Age or GnuPG, and backup just the password. (The encrypted file could be mirrored all over the place without fear of brute-forcing.)
Re: Show HN: PunchCard Key Backup
#16I love this so much. This, this right here is why I still visit Hacker News. I'm going to use this today and pave a path to my CNC router to make it stupidly easy to generate these plates on-demand.
Thus defeating the entire purpose! Unless you plan to wipe your router's firmware after every one.
If the CNC machine is not connected to a network, and (I don't know much about CNC, but I do wonder) if one can provide a generic program, then just fill in the parameters before execution, right at the machine, the secret would be confined to just the CNC machine.
Regardless, provided the CNC machine is not networked, and provided it doesn't have any solid state (only RAM), one could perhaps load a large job to overrite the previous one.
Although, perhaps the CNC machine could be used to just provide templates, with small indentations for where the holes could be punched, and additional engraving to provide a link to a document on how to use the card in case of disaster recovery.
Re: Show HN: PunchCard Key Backup
#17Cool but wouldn’t you forget how to decode it after some time? I.e. wouldn’t engraving regular characters be simpler?
Re: Show HN: PunchCard Key Backup
#18Earlier quoted context omitted.
Thus defeating the entire purpose! Unless you plan to wipe your router's firmware after every one.
If the CNC machine is not connected to a network, and (I don't know much about CNC, but I do wonder) if one can provide a generic program, then just fill in the parameters before execution, right at the machine, the secret would be confined to just the CNC machine. Regardless, provided the CNC machine is not networked, and provided it doesn't have any solid state (only RAM), one could perhaps load a large job to over…
Sometimes CNC machines are networked, sometimes not, but the idea behind saving keys like this is that you only generate the appropriate bits on disposable computers, e.g. a Raspberry Pi with an SD card you can then destroy.
It depends on how much money you want to secure, of course, so YMMV.
Re: Show HN: PunchCard Key Backup
#19Cool but wouldn’t you forget how to decode it after some time? I.e. wouldn’t engraving regular characters be simpler?
More data loss, harder to create.
Punch cards are stupid reliable.
Re: Show HN: PunchCard Key Backup
#20Just 128 bits? I expect punch cards to hold 80 columns of 12 bits :-)
I had to look it up, an IBM card format 80x12 is 187x83 mm. Roughly 0.06 bits/mm^2. The CR80 is 86x54mm for the 128bits, 0.03 bits/mm^2. Not a terrible difference for accommodating hand tools.
Edit: If my first search results are to be believed, the first magnetic hard drive had a density of 3.1 bits/mm^2