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Bitcoin => Development & Technical Discussion => Topic started by: ildubbioso on January 29, 2013, 12:40:51 AM



Title: Paper wallet: Different qr codes for the same address?
Post by: ildubbioso on January 29, 2013, 12:40:51 AM
I'm trying to send some btcs to my paper wallet for the second time (after 1 test), I don't have a smartphone, and so I must write down the address. Then I created the qrcode (with an online qr code generator) of the address and the qrcode from the paper is different (I can see with my eyes) than the online qrcode!  ??? I am a bit worried.

However, I tried with another address, I created another address with bitaddress and I generated another qrcode, they are different too.

What I am missing? Two different qrcodes can show the same address? And why it's always different when I do it online?


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: tbcoin on January 29, 2013, 12:53:21 AM
Yes, same info and diff code is normal

http://raidenii.net/files/datasheets/misc/qr_code.pdf

A lot of parameters http://qr-code-generator.certus.in/ (http://qr-code-generator.certus.in/)


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: ildubbioso on January 29, 2013, 01:03:26 AM
Yes, same info and diff code is normal

http://raidenii.net/files/datasheets/misc/qr_code.pdf

A lot of parameters http://qr-code-generator.certus.in/ (http://qr-code-generator.certus.in/)

Pheew  :) thanks.

However, without a smartphone wallet papers aren't so simple, but always useful.


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: DannyHamilton on January 29, 2013, 01:10:27 AM
. . . Two different qrcodes can show the same address? . . .

http://en.wikipedia.org/wiki/QR_code#Encoding

At a minimum there are 4 different possible error correction levels, and 8 different masks that can be used.  Just cycling through all the possible combinations of these can result in 8 x 4 = 32 different Qr Codes representing the exact same data.

The QR code can have any one of 4 different sizes (versions) increasing the number of QR Codes to represent the same data from 32 to 128.


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: ildubbioso on January 29, 2013, 01:11:44 AM
I have another question, are uppercase and lowercase important for the address? I have changed some letter from uppercase to lowercase and viceversa and blockchain shows me always the same address.
If it's true, why the address have lowercase and uppercase letters?


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: CIYAM on January 29, 2013, 01:14:21 AM
The case *is* crucial - you are probably seeing the effect of looking up "firstbits" which is when you do a search on the first x characters for an address (that search is case insensitive and merely tries the match the *first* address that starts case insensitively with what you typed as a convenience for "vanity address" usage).

You can search for 1CIYAM and you'll find my vanity address but if you sent anything to 1CIYAM... rather than 1ciyam... you would be sending it to the "great bit bucket in the sky"!


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: tbcoin on January 29, 2013, 01:16:59 AM
The case *is* crucial - you are probably seeing the effect of looking up "firstbits" which is when you do a search on the first x characters for an address (that search is case insensitive and merely tries the match the *first* address that starts case insensitively with what you typed).

+1

Blockchain.info use firstbits, is you use http://blockexplorer.com, you will see that this not happen


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: ildubbioso on January 29, 2013, 01:29:04 AM
The case *is* crucial - you are probably seeing the effect of looking up "firstbits" which is when you do a search on the first x characters for an address (that search is case insensitive and merely tries the match the *first* address that starts case insensitively with what you typed as a convenience for "vanity address" usage).


Quote
Blockchain.info use firstbits, is you use http://blockexplorer.com, you will see that this not happen

Thanks  :) I supposed something similar, however I cannot check because blockexplorer doesn't seem to work.


Title: Re: Paper wallet: Different qr codes for the same address?
Post by: spooderman on April 09, 2014, 02:02:52 PM
Thank you, I needed the information here also :)