Add specification for cashaddr #21

deadalnix · 2017-10-13T19:35:02Z

No description provided.

Mengerian · 2017-10-13T20:52:54Z

Very elegant proposal, I like it!

Another way of looking at the prefix, is that it can be treated as an "implicit" prefix. If, for some reason, applications have issues with "bitcoincash:" as a prefix, they can just handle the data portion. The "bitcoincash" is added for the checksum, so that should eliminate problems of ambiguous address formats.

In any case, it's nice to avoid the redundant double-prefix, such as "bitcoin:" and "bc1" in bech32

ftrader

Looks nice.

A couple of minor nits and some question (prefix and payload padding, case normalization relating to the QR encoding).

ftrader · 2017-10-14T10:43:04Z

cashaddr.md

+
+This document describes proposed address format to be used on Bitcoin Cash. It is a base32 encoded format using BCH codes as checksum and that can be used directly in links or QR codes.
+
+This format reuse the work done for Bech32[[1]](#bip173) and is similar is some aspects, but improves on others.


This format reuse the work done for Bech32[1] and is similar is some aspects, but improves on others.

Typos:

reuses

is similar in some aspects

ftrader · 2017-10-14T10:43:34Z

cashaddr.md

+
+## Abstract
+
+This document describes proposed address format to be used on Bitcoin Cash. It is a base32 encoded format using BCH codes as checksum and that can be used directly in links or QR codes.


describes a proposed address format

ftrader · 2017-10-14T10:46:16Z

cashaddr.md

+
+## Abstract
+
+This document describes proposed address format to be used on Bitcoin Cash. It is a base32 encoded format using BCH codes as checksum and that can be used directly in links or QR codes.


would be good to give a reference to type out the acronym for BCH and give a reference link when the acronym is first introduced in this spec. It's easily confused with current ticker used widely for Bitcoin Cash.

Bose–Chaudhuri–Hocquenghem (BCH)

ref. https://en.wikipedia.org/wiki/BCH_code

ftrader · 2017-10-14T10:47:11Z

cashaddr.md

+
+The version byte's most signficant bit is reserved and must be 0. The 4 next bits indicate the type of address and the 3 least significant bits indicate the size of the hash.
+
+| Size bits | Hash size in bits |


Since the paragraph above mentions that the type bits come first, it would be smoother to put the type bits explanation & table first instead of the hash bits.

ftrader · 2017-10-14T10:49:16Z

cashaddr.md

+
+#### Hash
+
+The hash part really deserve not much explaination as its meaning is dependent on the version field. It is the hash that represents the data, namely a hash of the public key for P2KH and the hash of the reedemScript for P2SH.


The part that readers will probably want to know is "how is this hash calculated".

Link to other spec would be good.

Some typo corrections:

deserves

explanation

ftrader · 2017-10-14T10:52:53Z

cashaddr.md

+The data to be fed are:
+1. The lower 5 bits of each characters of the prefix.
+2. A zero for the separator.
+3. The payload by chunks of 5 bits.


"in chunks of"

I think the spec should clarify how payload needs to be padded to split into 5-bit chunks

ftrader · 2017-10-14T10:53:37Z

cashaddr.md

+}
+````
+
+The data to be fed are:


It's pretty clear what is meant, but I would still suggest to make it clearer:

-> The checksum is calculated over the following data:

ftrader · 2017-10-14T10:55:03Z

cashaddr.md

+
+Lower case is preferred for cashaddr, but uppercase is accepted. A mixture of lower case and uppercase must be rejected.
+
+Allowing for uppercase ensure that the address can be encoded effisciently in QR codes using the alphanumeric mode[[2]](#alphanumqr).


Then why not normalize everything to uppercase before checksum computations?

Also typo:

efficiently

It doesn't chance anything, the text is not what is checksummed.

ftrader · 2017-10-14T10:55:28Z

cashaddr.md

+
+## Uppercase/lowercase
+
+Lower case is preferred for cashaddr, but uppercase is accepted. A mixture of lower case and uppercase must be rejected.


See question on paragraph below

ftrader · 2017-10-14T10:56:00Z

cashaddr.md

+
+In some contexts, such as payment URLs or QR codes, the addresses are currently prefixed with `bitcoincash:`. In these contexts, the address must not be double prefixed.
+
+## References


As indicated, a good reference for BCH codes linked to introduction would be nice.

Addressed in recent update.

DesWurstes · 2017-10-17T16:30:36Z

A Copay dev says they may cancel their new address format starting with C and switch to this proposal if this one becomes popular.

https://github.com/bitpay/copay/issues/6899#issuecomment-337210359

deadalnix · 2017-10-17T17:44:35Z

Updated the spec.

ftrader · 2017-10-17T18:02:05Z

cashaddr.md

+
+## References
+
+<a name="bch">[2]</a> https://en.wikipedia.org/wiki/BCH_code


ftrader · 2017-10-17T18:02:57Z

cashaddr.md

+The checksum is calculated over the following data:
+1. The lower 5 bits of each characters of the prefix.
+2. A zero for the separator (5 zero bits).
+3. The payload by chunks of 5 bits. The payload is padded with zero bits up t the point where it is a multiple of 5 bits.


up t -> up to

ftrader · 2017-10-17T18:03:52Z

cashaddr.md

+
+The prefix indicates the network on which this addess is valid. It is set to `bitcoincash` for Bitcoin Cash main net, `xbctest` for bitcoin cash testnet and `xbcreg` for bitcoin cash regtest.
+
+The prefix is followed by the spearator `:`.


spearator -> separator

deadalnix · 2017-10-17T21:03:03Z

Updated as per comments. I'll merge as @ftrader accepted and that comment are taken care of.

buzztiaan · 2017-10-19T13:28:45Z

the document is lacking motivation?

Spookerusa · 2017-10-20T20:31:11Z

I don't have a CLUE what you guys are talking about, but it sure makes me nervous about the whole thing.

ftrader suggested changes Oct 14, 2017

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DesWurstes mentioned this pull request Oct 14, 2017

[important] Deadalnix' Bech32 address proposal bitpay/wallet#6899

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deadalnix force-pushed the cashaddr branch from 1ed21af to b3fb356 Compare October 17, 2017 17:44

ftrader reviewed Oct 17, 2017

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cashaddr.md Outdated

## References

<a name="bch">[2]</a> https://en.wikipedia.org/wiki/BCH_code

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[2] -> [1]

ftrader reviewed Oct 17, 2017

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Add specification for cashaddr

2ae8a40

deadalnix force-pushed the cashaddr branch from b3fb356 to 2ae8a40 Compare October 17, 2017 21:02

deadalnix merged commit 0fbb64e into bitcoincashorg:master Oct 17, 2017

deadalnix deleted the cashaddr branch October 17, 2017 21:15

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Add specification for cashaddr #21

Add specification for cashaddr #21

deadalnix commented Oct 13, 2017

Mengerian commented Oct 13, 2017

ftrader left a comment •

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deadalnix Oct 17, 2017

ftrader Oct 14, 2017

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DesWurstes commented Oct 17, 2017

deadalnix commented Oct 17, 2017

ftrader Oct 17, 2017

ftrader Oct 17, 2017

ftrader Oct 17, 2017

deadalnix commented Oct 17, 2017

buzztiaan commented Oct 19, 2017

Spookerusa commented Oct 20, 2017


		This document describes proposed address format to be used on Bitcoin Cash. It is a base32 encoded format using BCH codes as checksum and that can be used directly in links or QR codes.

		This format reuse the work done for Bech32[[1]](#bip173) and is similar is some aspects, but improves on others.


		## Abstract

		This document describes proposed address format to be used on Bitcoin Cash. It is a base32 encoded format using BCH codes as checksum and that can be used directly in links or QR codes.


		The version byte's most signficant bit is reserved and must be 0. The 4 next bits indicate the type of address and the 3 least significant bits indicate the size of the hash.

		\| Size bits \| Hash size in bits \|


		#### Hash

		The hash part really deserve not much explaination as its meaning is dependent on the version field. It is the hash that represents the data, namely a hash of the public key for P2KH and the hash of the reedemScript for P2SH.


		Lower case is preferred for cashaddr, but uppercase is accepted. A mixture of lower case and uppercase must be rejected.

		Allowing for uppercase ensure that the address can be encoded effisciently in QR codes using the alphanumeric mode[[2]](#alphanumqr).


		## Uppercase/lowercase

		Lower case is preferred for cashaddr, but uppercase is accepted. A mixture of lower case and uppercase must be rejected.


		In some contexts, such as payment URLs or QR codes, the addresses are currently prefixed with `bitcoincash:`. In these contexts, the address must not be double prefixed.

		## References


		## References

		<a name="bch">[2]</a> https://en.wikipedia.org/wiki/BCH_code


		The prefix indicates the network on which this addess is valid. It is set to `bitcoincash` for Bitcoin Cash main net, `xbctest` for bitcoin cash testnet and `xbcreg` for bitcoin cash regtest.

		The prefix is followed by the spearator `:`.

Add specification for cashaddr #21

Add specification for cashaddr #21

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deadalnix commented Oct 13, 2017

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DesWurstes commented Oct 17, 2017

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deadalnix commented Oct 17, 2017

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Spookerusa commented Oct 20, 2017

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