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| + | {{bip}} |
| + | {{BipMoved|bip-0021.mediawiki}} |
| + | |
| + | == History == |
| {{infobox BIP | | {{infobox BIP |
| |name=BIP 0021 | | |name=BIP 0021 |
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| }}'''BIP 0021''' is a modification of an earlier [[BIP 0020]] by [[Luke Dashjr]]. BIP 0020 was based off an earlier document by [[Nils Schneider]]. The alternative payment amounts in BIP 0020 have been removed. | | }}'''BIP 0021''' is a modification of an earlier [[BIP 0020]] by [[Luke Dashjr]]. BIP 0020 was based off an earlier document by [[Nils Schneider]]. The alternative payment amounts in BIP 0020 have been removed. |
| | | |
− | {{BIP begin}}
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− | ==Abstract==
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− | This BIP proposes a URI scheme for making Bitcoin payments.
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− |
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− | ==Motivation==
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− | The purpose of this URI scheme is to enable users to easily make payments by simply clicking links on webpages or scanning QR Codes.
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− |
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− | ==Specification==
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− |
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− | === General rules for handling (important!) ===
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− |
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− | Bitcoin clients MUST NOT act on URIs without getting the user's authorization.
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− | They SHOULD require the user to manually approve each payment individually, though in some cases they MAY allow the user to automatically make this decision.
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− |
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− | === Operating system integration ===
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− | Graphical bitcoin clients SHOULD register themselves as the handler for the "bitcoin:" URI scheme by default, if no other handler is already registered. If there is already a registered handler, they MAY prompt the user to change it once when they first run the client.
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− |
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− | === General Format ===
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− |
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− | Bitcoin URIs follow the general format for URIs as set forth in RFC 3986. The path component consists of a bitcoin address, and the query component provides additional payment options.
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− |
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− | Elements of the query component may contain characters outside the valid range. These must first be encoded according to UTF-8, and then each octet of the corresponding UTF-8 sequence must be percent-encoded as described in RFC 3986.
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− |
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− | === ABNF grammar ===
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− |
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− | (See also [[#Simpler syntax|a simpler representation of syntax]])
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− |
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− | bitcoinurn = "bitcoin:" bitcoinaddress [ "?" bitcoinparams ]
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− | bitcoinaddress = *base58
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− | bitcoinparams = bitcoinparam [ "&" bitcoinparams ]
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− | bitcoinparam = [ amountparam / labelparam / messageparam / otherparam / reqparam ]
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− | amountparam = "amount=" *digit [ "." *digit ]
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− | labelparam = "label=" *qchar
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− | messageparam = "message=" *qchar
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− | otherparam = qchar *qchar [ "=" *qchar ]
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− | reqparam = "req-" qchar *qchar [ "=" *qchar ]
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− |
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− | Here, "qchar" corresponds to valid characters of an RFC 3986 URI query component, excluding the "=" and "&" characters, which this BIP takes as separators.
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− |
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− | The scheme component ("bitcoin:") is case-insensitive, and implementations must accept any combination of uppercase and lowercase letters. The rest of the URI is case-sensitive, including the query parameter keys.
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− |
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− | === Query Keys ===
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− |
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− | *label: Label for that address (e.g. name of receiver)
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− | *address: bitcoin address
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− | *message: message that describes the transaction to the user ([[#Examples|see examples below]])
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− | *size: amount of base bitcoin units ([[#Transfer amount/size|see below]])
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− | *(others): optional, for future extensions
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− |
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− | ==== Transfer amount/size ====
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− |
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− | If an amount is provided, it MUST be specified in decimal BTC.
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− | All amounts MUST contain no commas and use a period (.) as the separating character to separate whole numbers and decimal fractions.
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− | I.e. amount=50.00 or amount=50 is treated as 50 BTC, and amount=50,000.00 is invalid.
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− |
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− | Bitcoin clients MAY display the amount in any format that is not intended to deceive the user.
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− | They SHOULD choose a format that is foremost least confusing, and only after that most reasonable given the amount requested.
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− | For example, so long as the majority of users work in BTC units, values should always be displayed in BTC by default, even if mBTC or TBC would otherwise be a more logical interpretation of the amount.
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− | == Rationale ==
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− |
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− | ===Payment identifiers, not person identifiers===
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− | Current best practices are that a unique address should be used for every transaction.
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− | Therefore, a URI scheme should not represent an exchange of personal information, but a one-time payment.
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− |
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− | ===Accessibility (URI scheme name)===
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− | Should someone from the outside happen to see such a URI, the URI scheme name already gives a description.
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− | A quick search should then do the rest to help them find the resources needed to make their payment.
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− | Other proposed names sound much more cryptic; the chance that someone googles that out of curiosity are much slimmer.
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− | Also, very likely, what he will find are mostly technical specifications - not the best introduction to bitcoin.
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− |
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− | ==Forward compatibility==
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− | Variables which are prefixed with a req- are considered required. If a client does not implement any variables which are prefixed with req-, it MUST consider the entire URI invalid. Any other variables which are not implemented, but which are not prefixed with a req-, can be safely ignored.
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− |
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− | ==Backward compatibility==
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− | As this BIP is written, several clients already implement a bitcoin: URI scheme similar to this one, however usually without the additional "req-" prefix requirement. Thus, it is recommended that additional variables prefixed with req- not be used in a mission-critical way until a grace period of 6 months from the finalization of this BIP has passed in order to allow client developers to release new versions, and users of old clients to upgrade.
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− |
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− | == Appendix ==
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− |
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− | === Simpler syntax ===
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− |
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− | This section is non-normative and does not cover all possible syntax.
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− | Please see the BNF grammar above for the normative syntax.
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− |
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− | [foo] means optional, <bar> are placeholders
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− |
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− | <nowiki>bitcoin:<address>[?amount=<amount>][?label=<label>][?message=<message>]</nowiki>
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− |
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− | === Examples ===
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− |
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− | Just the address:
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− | bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W
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− |
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− | Address with name:
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− | bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?label=Luke-Jr
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− |
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− | Request 20.30 BTC to "Luke-Jr":
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− | bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?amount=20.3&label=Luke-Jr
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− |
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− | Request 50 BTC with message:
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− | bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?amount=50&label=Luke-Jr&message=Donation%20for%20project%20xyz
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− |
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− | Some future version that has variables which are (currently) not understood and required and thus invalid:
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− | bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?req-somethingyoudontunderstand=50&req-somethingelseyoudontget=999
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− |
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− | Some future version that has variables which are (currently) not understood but not required and thus valid:
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− | bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?somethingyoudontunderstand=50&somethingelseyoudontget=999
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− |
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− | Characters must be URI encoded properly.
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| | | |
− | == Reference Implementations ==
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− | === Bitcoin clients ===
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− | * Bitcoin-Qt supports the old version of Bitcoin URIs (ie without the req- prefix), with Windows and KDE integration as of commit 70f55355e29c8e45b607e782c5d76609d23cc858.
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− | {{end}}
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| [[Category:Developer]] | | [[Category:Developer]] |
| [[Category:Technical]] | | [[Category:Technical]] |
| [[Category:BIP|D]] | | [[Category:BIP|D]] |