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Is it possible to send bitcoins with an attached message with the transaction? If yes how to do it?
How to send bitcoin with a message attached
Answers
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The payment protocol (see BIP 70-72) will support attaching messages to transactions.
Note that these messages do not end up in the blockchain, which is the right way to do it, as they are private information between sender and receiver - no need to make the entire world replicate it.
4where does these messages get stored and how are they being processed to be sent to the recipient? If its sent via email, who is sending the email and doesn't that mean the merchant have to have something in place to send these emails? – Patoshi パトシ – 2017-03-04T19:00:06.323
1They're in the sender and the receiver wallet, and the message is communicated through whatever means is used to convey the payment request. A better response to this question these days is how Lightning payments also can have messages associated, even though there is not even a transaction on chain for the payment. – Pieter Wuille – 2018-04-07T14:38:59.443
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If you are just looking to encode a message into the URI, then look at BIP 20. If you want to actually associate the message in the block chain, then I would take a look at this stack overflow question.
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Technical details of how to do this are dicussed here. https://bitcoin.stackexchange.com/search?q=encode+message+in+the+block+chain The best way seems to be using the transaction output script.
Blockchain.info has this capabilities in it's wallets. Not sure what other wallets allow it.
1have you tried to send a transaction with a message in bitcoin-qt? – V-X – 2014-01-05T19:35:59.527
1yes. but I couldn't figure out how – Sathish Manohar – 2014-01-05T19:50:53.597
isn't there something like this? – V-X – 2014-01-05T19:59:48.127
1@V-X That creates a signed message, but the question is about whether you can attach that signed message to a transaction. – David Schwartz – 2014-01-05T20:37:16.953
1I believe there are some chains that allow that. I'm not sure if it has been merged upstream to bitcoin or not. I know I've been discussing ways to do messaging within a coin blockchain (vs bitmessage). You could use a blockchain.info wallet and send a message over blockchain.info. – Joe White – 2014-01-05T21:20:17.600
5Bitcoin transactions are not supposed to contain messages; only what is necessary for the world to validate your transaction. The rest is private information between you and the receiver, and just spam to the rest of the world. – Pieter Wuille – 2014-03-12T00:57:55.693
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If you really have to do this, then please use OP_RETURN.
– Jozef – 2014-10-15T08:42:23.000