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Topic: More compact encoding for bitcoin QR codes? (Read 928 times)

jr. member
Activity: 55
Merit: 2
April 10, 2014, 05:21:04 PM
#5
I mean common ones

Correct, in general we cannot make the QR code smaller if the QR scanner expects the address (or key) in base58-encoded ASCII format. However my question was why don't we just encode the binary address (or key) in QR code? It would allow smaller QR code, or cleaner/more robust QR code given the same footprint.
rme
hero member
Activity: 756
Merit: 504
I mean common ones
jr. member
Activity: 55
Merit: 2
For reference, this is the smallest size of a Bitcoin address qr code:

http://chart.apis.google.com/chart?cht=qr&chs=100x100&chl=[url]bitcoin:1R2sWeVhFitB8zVbkrmdSoXzaQRsw6cfh&chld=M[/url]|0

Not really, you can make the QR code smaller if your Bitcoin address is made up of entirely numbers and upper-case letters.

Example: (Tips welcome!)

It can be even smaller if the address is made up of only numbers, but it is probably not possible for anybody to find a corresponding private key:

Example: (Don't send coins here!)
rme
hero member
Activity: 756
Merit: 504
For reference, this is the smallest size of a Bitcoin address qr code:

http://chart.apis.google.com/chart?cht=qr&chs=100x100&chl=[url]bitcoin:1R2sWeVhFitB8zVbkrmdSoXzaQRsw6cfh&chld=M[/url]|0
jr. member
Activity: 55
Merit: 2
More compact encoding for bitcoin QR codes?

Most bitcoin-related QR codes encode the base58check ASCII string in byte mode. For example the QR code for address 1JwSSubhmg6iPtRjtyqhUYYH7bZg3Lfy1T actually encodes the byte sequence "314a7753537562686d6736695074526a747971685559594837625a67334c66793154".

But this is rather wasteful. We could have just encoded the binary form of the address with checksum, "00c4c5d791fcb4654a1ef5e03fe0ad3d9c598f98274abb8f1a". It would allow a smaller QR code.
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