[bitcoin-dev] Human readable checksum (verification code) to avoid errors on BTC public addresses

[ts]

Entering a BTC address for a transaction can pose a risk of error (human or technical). While 
there is a checksum integrated in BTC addresses already, this is used only at a technical 
level and does not avoid entering a valid but otherwise wrong address. Moreover, it does not 
improve the overall user experience.

In case this hasn't been discussed before, I propose to implement a 3 or 4 digit code (lets 
call it 4DC for this text), generated as checksum from the address. This 4DC should be shown 
in all wallets next to the receiving address. When entering a new address to send BTC, the 
sending wallet should also show the 4DC next to the entered address. This way, the sending 
person can easily verify that the resulting 4DC matches the one from the receiving address.

This would mean that a receiver would not only send his public address to the sender, but also 
the 4DC. A minor disadvantage since a) it is not mandatory and b) it is very easy to do. 
However, it would greatly reduce the probability of performing transactions to a wrong address.

Technically, this is very easy to implement. The only effort needed is agreeing on a checksum 
standard to generate the code. Once the standard is established, all wallet and exchange 
developers can start implementing this.

Agreeing on a good name for this code would be helpful for a fast adoption (human readable 
checksum, verification code or 4DC are just examples).

Obviously, this solution could be used for all other coins/networks. But ideally, each of them 
should have its own checksum algorithm, in order to further avoid sending funds to the wrong 
network. Especially when the address standard is the same like it is the case with BTC and BCH.

Hopefully, Bitcoin can implement this first and serve as example-to-follow to other 
coins/networks.

Cheers,
TS