Standard Check Numbers (checksums for addresses)

[grue]

Me??? No.  Take a look at this thread. I think you'll find that I was the very first person to explain to the OP that there is a checksum built in to the address.  I'm just trying to help people guess why the OP might want an additional checksum.  (See my previous guess at an imaginary scenario here.)

this is getting ridiculous. i guess we can extend this argument to adding a 1MB checksum to every bitcoin address just in case

Without a client how are you going to compute the "external checksum"?

I don't run a client when I'm at work, but I can easily run:

Code:

echo "1bitcoinaddress" | my_favorite_checksum

so we have to add all this useless overhead just because someone doesn't want to install a simple tool?

[DannyHamilton]

this is getting ridiculous. i guess we can extend this argument to adding a 1MB checksum to every bitcoin address just in case

Getting ridiculous? When wasn't it ridiculous?  I don't see how a 1MB checksum added to the address would make any difference.  Just in case of what?

so we have to add all this useless overhead just because someone doesn't want to install a simple tool?

What overhead? Which tool?

[grue]

this is getting ridiculous. i guess we can extend this argument to adding a 1MB checksum to every bitcoin address just in case

Getting ridiculous? When wasn't it ridiculous?  I don't see how a 1MB checksum added to the address would make any difference.  Just in case of what?

you're saying a checksum isn't enough, and we want to be even more sure, so i'm extending the argument to a 1MB checksum just in case of a 1 in a gazillion chance typo

so we have to add all this useless overhead just because someone doesn't want to install a simple tool?

What overhead? Which tool?

overhead = all the extra chatter resulting from exchanging checksums, requesting a compare, acknowledging the checksum, and calculation of the extra checksum on both sides.

it's trivial to install a command line tool (or even a bash script) that simply verifies a bitcoin address, rather than adding additional checksums. if you have the facilities to compute a reliable checksum, you can also just as easily check a bitcoin address.

[DannyHamilton]

Getting ridiculous? When wasn't it ridiculous?  I don't see how a 1MB checksum added to the address would make any difference.  Just in case of what?

you're saying a checksum isn't enough, and we want to be even more sure . . .

Me? I never said any such thing.  You really need to pay closer attention when you read.

What overhead? Which tool?

overhead = all the extra chatter resulting from exchanging checksums, requesting a compare, acknowledging the checksum, and calculation of the extra checksum on both sides.

Exactly. The OP is trying to reduce some of that overhead by having the Bitcoin-Qt client display the checksum next to the address.  That way they don't need to calculate it on their side.  The person who receives the address would calculate it, and the person sending the address would glance at their own client (or have the checksum written/memorized?)

it's trivial to install a command line tool (or even a bash script) that simply verifies a bitcoin address, rather than adding additional checksums. if you have the facilities to compute a reliable checksum, you can also just as easily check a bitcoin address.

Perhaps if someone would have pointed the OP at such a tool or script, we could have avoided most of this discussion.  Nobody seemed to be aware of any such thing.

[grue]

What overhead? Which tool?

overhead = all the extra chatter resulting from exchanging checksums, requesting a compare, acknowledging the checksum, and calculation of the extra checksum on both sides.

Exactly. The OP is trying to reduce some of that overhead by having the Bitcoin-Qt client display the checksum next to the address.  That way they don't need to calculate it on their side.  The person who receives the address would calculate it, and the person sending the address would glance at their own client (or have the checksum written/memorized?)

so why doesn't the existing checksum not satisfy that requirement?

[DannyHamilton]

What overhead? Which tool?

overhead = all the extra chatter resulting from exchanging checksums, requesting a compare, acknowledging the checksum, and calculation of the extra checksum on both sides.

Exactly. The OP is trying to reduce some of that overhead by having the Bitcoin-Qt client display the checksum next to the address.  That way they don't need to calculate it on their side.  The person who receives the address would calculate it, and the person sending the address would glance at their own client (or have the checksum written/memorized?)

so why doesn't the existing checksum not satisfy that requirement?

As far as I'm concerned it does.

As far as I can tell from what the OP had said, it seems that he was concerned about a situation where the person receiving the address wouldn't have access to a bitcoin client to validate the address but would have access to some sort of "standard" checksum program.  A checksum that would not be given to the the receiver of the address but which he could quickly/easily generate and give back for the address sender to validate against what the address sender has from his own client.

[jl2012]

Am I really the only one who makes detailed comparisons between bitcoin addresses to ensure they are the same?

I guess I must just be paranoid, maybe it's the irreversibility of a bitcoin transaction that scares me.

I usually compare the first few characters, a few characters in the middle, and the last few characters. That should be good enough because the last few characters are actually the checksum that you want (by double SHA256, not CRC).