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224 lines
7.8 KiB
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224 lines
7.8 KiB
Plaintext
---------------------------------------------------
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BIP: 21
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Title: URI Scheme
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Author: Nils Schneider <nils.schneider@gmail.com>
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Matt Corallo <bip21@bluematt.me>
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Status: Accepted
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Type: Standards Track
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Created: 2012-01-29
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---------------------------------------------------
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This BIP is a modification of an earlier link:bip-0020.mediawiki[BIP
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0020] by Luke Dashjr. BIP 0020 was based off an earlier document by Nils
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Schneider. The alternative payment amounts in BIP 0020 have been
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removed.
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[[abstract]]
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Abstract
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~~~~~~~~
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This BIP proposes a URI scheme for making Bitcoin payments.
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[[motivation]]
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Motivation
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~~~~~~~~~~
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The purpose of this URI scheme is to enable users to easily make
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payments by simply clicking links on webpages or scanning QR Codes.
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[[specification]]
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Specification
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~~~~~~~~~~~~~
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[[general-rules-for-handling-important]]
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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
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authorization. They SHOULD require the user to manually approve each
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payment individually, though in some cases they MAY allow the user to
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automatically make this decision.
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[[operating-system-integration]]
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Operating system integration
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Graphical bitcoin clients SHOULD register themselves as the handler for
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the "bitcoin:" URI scheme by default, if no other handler is already
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registered. If there is already a registered handler, they MAY prompt
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the user to change it once when they first run the client.
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[[general-format]]
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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
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3986. The path component consists of a bitcoin address, and the query
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component provides additional payment options.
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Elements of the query component may contain characters outside the valid
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range. These must first be encoded according to UTF-8, and then each
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octet of the corresponding UTF-8 sequence must be percent-encoded as
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described in RFC 3986.
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[[abnf-grammar]]
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ABNF grammar
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^^^^^^^^^^^^
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(See also link:#Simpler_syntax[a simpler representation of syntax])
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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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Here, "qchar" corresponds to valid characters of an RFC 3986 URI query
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component, excluding the "=" and "&" characters, which this BIP takes as
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separators.
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The scheme component ("bitcoin:") is case-insensitive, and
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implementations must accept any combination of uppercase and lowercase
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letters. The rest of the URI is case-sensitive, including the query
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parameter keys.
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[[query-keys]]
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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
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(link:#Examples[see examples below])
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* size: amount of base bitcoin units (link:#Transfer_amount/size[see
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below])
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* (others): optional, for future extensions
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[[transfer-amountsize]]
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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. All
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amounts MUST contain no commas and use a period (.) as the separating
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character to separate whole numbers and decimal fractions. I.e.
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amount=50.00 or amount=50 is treated as 50 BTC, and amount=50,000.00 is
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invalid.
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Bitcoin clients MAY display the amount in any format that is not
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intended to deceive the user. They SHOULD choose a format that is
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foremost least confusing, and only after that most reasonable given the
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amount requested. For example, so long as the majority of users work in
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BTC units, values should always be displayed in BTC by default, even if
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mBTC or TBC would otherwise be a more logical interpretation of the
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amount.
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[[rationale]]
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Rationale
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~~~~~~~~~
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[[payment-identifiers-not-person-identifiers]]
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Payment identifiers, not person identifiers
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Current best practices are that a unique address should be used for
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every transaction. Therefore, a URI scheme should not represent an
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exchange of personal information, but a one-time payment.
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[[accessibility-uri-scheme-name]]
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Accessibility (URI scheme name)
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^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
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Should someone from the outside happen to see such a URI, the URI scheme
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name already gives a description. A quick search should then do the rest
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to help them find the resources needed to make their payment. Other
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proposed names sound much more cryptic; the chance that someone googles
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that out of curiosity are much slimmer. Also, very likely, what he will
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find are mostly technical specifications - not the best introduction to
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bitcoin.
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[[forward-compatibility]]
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Forward compatibility
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~~~~~~~~~~~~~~~~~~~~~
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Variables which are prefixed with a req- are considered required. If a
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client does not implement any variables which are prefixed with req-, it
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MUST consider the entire URI invalid. Any other variables which are not
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implemented, but which are not prefixed with a req-, can be safely
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ignored.
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[[backward-compatibility]]
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Backward compatibility
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~~~~~~~~~~~~~~~~~~~~~~
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As this BIP is written, several clients already implement a bitcoin: URI
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scheme similar to this one, however usually without the additional
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"req-" prefix requirement. Thus, it is recommended that additional
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variables prefixed with req- not be used in a mission-critical way until
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a grace period of 6 months from the finalization of this BIP has passed
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in order to allow client developers to release new versions, and users
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of old clients to upgrade.
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[[appendix]]
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Appendix
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~~~~~~~~
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[[simpler-syntax]]
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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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[foo] means optional, <bar> are placeholders
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`bitcoin:<address>[?amount=<amount>][?label=<label>][?message=<message>]`
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[[examples]]
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Examples
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^^^^^^^^
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Just the address:
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bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W[`bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W`]
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Address with name:
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bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?label=Luke-Jr[`bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?label=Luke-Jr`]
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Request 20.30 BTC to "Luke-Jr":
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bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?amount=20.3&label=Luke-Jr[`bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?amount=20.3&label=Luke-Jr`]
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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[`bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?amount=50&label=Luke-Jr&message=Donation%20for%20project%20xyz`]
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Some future version that has variables which are (currently) not
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understood and required and thus invalid:
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bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?req-somethingyoudontunderstand=50&req-somethingelseyoudontget=999[`bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?req-somethingyoudontunderstand=50&req-somethingelseyoudontget=999`]
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Some future version that has variables which are (currently) not
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understood but not required and thus valid:
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bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?somethingyoudontunderstand=50&somethingelseyoudontget=999[`bitcoin:175tWpb8K1S7NmH4Zx6rewF9WQrcZv245W?somethingyoudontunderstand=50&somethingelseyoudontget=999`]
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Characters must be URI encoded properly.
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[[reference-implementations]]
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Reference Implementations
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~~~~~~~~~~~~~~~~~~~~~~~~~
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[[bitcoin-clients]]
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Bitcoin clients
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^^^^^^^^^^^^^^^
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* Bitcoin-Qt supports the old version of Bitcoin URIs (ie without the
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req- prefix), with Windows and KDE integration as of commit
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70f55355e29c8e45b607e782c5d76609d23cc858.
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