I would like to propose a BIP that specifies a format for the export and import of labels from a wallet. While transferring access to funds across wallet applications has been made simple through standards such as BIP39, wallet labels remain siloed and difficult to extract despite their value, particularly in a privacy context.
The proposed format is a simple two column CSV file, with the reference to a transaction, address, input or output in the first column, and the label in the second column. CSV was chosen for its wide accessibility, especially to users without specific technical expertise. Similarly, the CSV file may be compressed using the ZIP format, and optionally encrypted using AES.
Feedback is appreciated.
<pre>
BIP: wallet-labels
Layer: Applications
Title: Wallet Labels Export Format
Author: Craig Raw <
craig@sparrowwallet.com>
Comments-Summary: No comments yet.
Comments-URI:
https://github.com/bitcoin/bips/wiki/Comments:BIP-wallet-labels Status: Draft
Type: Informational
Created: 2022-08-23
License: BSD-2-Clause
</pre>
==Abstract==
This document specifies a format for the export of labels that may be attached to the transactions, addresses, input and outputs in a wallet.
==Copyright==
This BIP is licensed under the BSD 2-clause license.
==Motivation==
The export and import of funds across different Bitcoin wallet applications is well defined through standards such as BIP39, BIP32, BIP44 etc.
These standards are well supported and allow users to move easily between different wallets.
There is, however, no defined standard to transfer any labels the user may have applied to the transactions, addresses, inputs or outputs in their wallet.
The UTXO model that Bitcoin uses makes these labels particularly valuable as they may indicate the source of funds, whether received externally or as a result of change from a prior transaction.
In both cases, care must be taken when spending to avoid undesirable leaks of private information.
Labels provide valuable guidance in this regard, and have even become mandatory when spending in several Bitcoin wallets.
Allowing users to export their labels in a standardized way ensures that they do not experience lock-in to a particular wallet application.
In addition, by using common formats, this BIP seeks to make manual or bulk management of labels accessible to users without specific technical expertise.
==Specification==
In order to make the import and export of labels as widely accessible as possible, this BIP uses the comma separated values (CSV) format, which is widely supported by consumer, business, and scientific applications.
Although the technical specification of CSV in RFC4180 is not always followed, the application of the format in this BIP is simple enough that compatibility should not present a problem.
Moreover, the simplicity and forgiving nature of CSV (over for example JSON) lends itself well to bulk label editing using spreadsheet and text editing tools.
A CSV export of labels from a wallet must be a UTF-8 encoded text file, containing one record per line, with records containing two fields delimited by a comma.
The fields may be quoted, but this is unnecessary, as the first comma in the line will always be the delimiter.
The first line in the file is a header, and should be ignored on import.
Thereafter, each line represents a record that refers to a label applied in the wallet.
The order in which these records appear is not defined.
The first field in the record contains a reference to the transaction, address, input or output in the wallet.
This is specified as one of the following:
* Transaction ID (<tt>txid</tt>)
* Address
* Input (rendered as <tt>txid<index</tt>)
* Output (rendered as <tt>txid>index</tt> or <tt>txid:index</tt>)
The second field contains the label applied to the reference.
Exporting applications may omit records with no labels or labels of zero length.
Files exported should use the <tt>.csv</tt> file extension.
In order to reduce file size while retaining wide accessibility, the CSV file may be compressed using the ZIP file format, using the <tt>.zip</tt> file extension.
This <tt>.zip</tt> file may optionally be encrypted using either AES-128 or AES-256 encryption, which is supported by numerous applications including Winzip and 7-zip.
In order to ensure that weak encryption does not proliferate, importers following this standard must refuse to import <tt>.zip</tt> files encrypted with the weaker Zip 2.0 standard.
The textual representation of the wallet's extended public key (as defined by BIP32, with an <tt>xpub</tt> header) should be used as the password.
==Importing==
When importing, a naive algorithm may simply match against any reference, but it is possible to disambiguate between transactions, addresses, inputs and outputs.
For example in the following pseudocode:
<pre>
if reference length < 64
Set address label
else if reference length == 64
Set transaction label
else if reference contains '<'
Set input label
else
Set output label
</pre>
Importing applications may truncate labels if necessary.
==Test Vectors==
The following fragment represents a wallet label export:
<pre>
Reference,Label
c3bdad6e7dcd7997e16a5b7b7cf4d8f6079820ff2eedd5fcbb2ad088f767b37b,Transaction
1A69TXnEM2ms9fMaY9UuiJ7415X7xZaUSg,Address
c3bdad6e7dcd7997e16a5b7b7cf4d8f6079820ff2eedd5fcbb2ad088f767b37b<0,Input
c3bdad6e7dcd7997e16a5b7b7cf4d8f6079820ff2eedd5fcbb2ad088f767b37b>0,Output
c3bdad6e7dcd7997e16a5b7b7cf4d8f6079820ff2eedd5fcbb2ad088f767b37b:0,Output (alternative)
</pre>
==Reference Implementation==
TBD