* [Bitcoin-development] Reusable payment codes
@ 2015-04-24 20:00 Justus Ranvier
2015-04-24 20:58 ` Gregory Maxwell
` (2 more replies)
0 siblings, 3 replies; 11+ messages in thread
From: Justus Ranvier @ 2015-04-24 20:00 UTC (permalink / raw)
To: Bitcoin Dev
[-- Attachment #1: Type: text/plain, Size: 1620 bytes --]
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
https://github.com/justusranvier/rfc/blob/payment_code/bips/bip-pc01.mediawiki
This link contains an RFC for a new type of Bitcoin address called a
"payment code"
Payment codes are SPV-friendly alternatives to DarkWallet-style stealth
addresses which provide useful features such as positively identifying
senders to recipients and automatically providing for transaction refunds.
Payment codes can be publicly advertised and associated with a real-life
identity without causing a loss of financial privacy.
Compared to stealth addresses, payment codes require less blockchain data
storage.
Payment codes require 65 bytes of OP_RETURN data per sender-recipient pair,
while stealth addresses require 40 bytes per transaction.
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^ permalink raw reply [flat|nested] 11+ messages in thread* Re: [Bitcoin-development] Reusable payment codes 2015-04-24 20:00 [Bitcoin-development] Reusable payment codes Justus Ranvier @ 2015-04-24 20:58 ` Gregory Maxwell [not found] ` <CAHabJ+MtWJS=e3tkGih=xoP4ARgHe8X=D_p9OWTnRJi0z9epBw@mail.gmail.com> [not found] ` <1AE7B0A2-90EE-42EE-9D30-4DC1B5892E53@newcastle.ac.uk> 2015-06-16 16:26 ` [Bitcoin-development] " odinn 2 siblings, 1 reply; 11+ messages in thread From: Gregory Maxwell @ 2015-04-24 20:58 UTC (permalink / raw) To: Justus Ranvier; +Cc: Bitcoin Dev On Fri, Apr 24, 2015 at 8:00 PM, Justus Ranvier <justus.ranvier@monetas•net> wrote: > https://github.com/justusranvier/rfc/blob/payment_code/bips/bip-pc01.mediawiki > > This link contains an RFC for a new type of Bitcoin address called a > "payment code" > > Payment codes are SPV-friendly alternatives to DarkWallet-style stealth > addresses which provide useful features such as positively identifying > senders to recipients and automatically providing for transaction refunds. So this requires making dust payments to a constantly reused address in order to (ab)use the blockchain as a messaging layer. Indeed, this is more SPV compatible; but it seems likely to me that _in practice_ it would almost completely undermine the privacy the idea hoped to provide; because you'd have an observable linkage to a highly reused address. It would also more than double the data sent for the application where 'stealth addresses' are most important: one-time anonymous donations (in other contexts; you have two way communication between the participants, and so you can just given them a one off address without singling in the public network.) > Alice selects the first exposed public key of the first input of the transaction So this creates strong "binding" that we would really strongly like to avoid in the network; basically what this says is that "You can only pay to person X if you use scheme Y for your own Bitcoins"-- who says any of your inputs have a ECDH pubkey at all? Of if they do, who says its one that you have access to the private key for for use in this scheme (e.g. it could be in a HSM that only signs according to a policy). We should avoid creating txout features that restrict what kind of scriptPubkey the sender can use, or otherwise we'll never be able to deploy new signature features. (We can see how long P2SH took to gain adoption because some wallets refused to implement sending to it, even though doing so was trivial). This kind of binding was intentionally designed out of the stealth address proposal; I think this scheme can be made to work without any increase in size by reusing the payment code as the ephemeral public key (or actually being substantially smaller e.g. use the shared secret as the chain code, but I should give it more thought) Also, SPV wallets do not need to have access to the public keys being spent by a particular transaction they learn about; providing that access is fundamentally expensive and pushes things back towards centralization. > in uncompressed DER format This is fundamentally more expensive to compute; please don't specify "uncompressed". This appears incompatible with multisignature; which is unfortunate. I do very much like the fact that this scheme establishes a shared chain once and then doesn't need to reestablish; this was one of the improvements I wanted for the stealth address. I'm disappointed that there isn't any thought given to solving the scanning privacy without forcing non-private pure-overhead messaging transactions on heavily reused addresses. Are you aware of the IBE approach that allows someone to request a third party scan for them with block by block control over their delegation of scanning? ^ permalink raw reply [flat|nested] 11+ messages in thread
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* [Bitcoin-development] Fwd: Reusable payment codes [not found] ` <CAHabJ+MtWJS=e3tkGih=xoP4ARgHe8X=D_p9OWTnRJi0z9epBw@mail.gmail.com> @ 2015-04-25 0:20 ` Justus Ranvier [not found] ` <CAHabJ+Oabx80+_1KutfrPUt5QEnMivfNeeh4uJJJOsiHRQqSZw@mail.gmail.com> 1 sibling, 0 replies; 11+ messages in thread From: Justus Ranvier @ 2015-04-25 0:20 UTC (permalink / raw) To: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 3849 bytes --] On Fri, Apr 24, 2015 at 10:58 PM, Gregory Maxwell <gmaxwell@gmail•com> wrote: > So this requires making dust payments to a constantly reused address > in order to (ab)use the blockchain as a messaging layer. > > Indeed, this is more SPV compatible; but it seems likely to me that > _in practice_ it would almost completely undermine the privacy the > idea hoped to provide; because you'd have an observable linkage to a > highly reused address. > I agree that the output associated with notification transactions would require special handling to avoid privacy leaks. At a minimum they'd require mixing or being donated to miners as a transaction fee. > > It would also more than double the data sent for the application where > 'stealth addresses' are most important: one-time anonymous donations > (in other contexts; you have two way communication between the > participants, and so you can just given them a one off address without > singling in the public network.) > Communication is only one way, except for the case in which the recipient wants to send a refund. Assuming no refund and only a single anonymous donation in the lifetime of the sender's identity, payment codes would require 65 bytes vs 40 bytes for stealth addresses. As soon as the sender sends more than one donation to the same recipient, payment codes show an space advantage over stealth addresses. This kind of binding was intentionally designed out of the stealth > address proposal; I think this scheme can be made to work without any > increase in size by reusing the payment code as the ephemeral public > key (or actually being substantially smaller e.g. use the shared > secret as the chain code, but I should give it more thought) > With 97 byte standard OP_RETURN values the ephemeral public key could be appended to the chain code, but that's undesirable for other reasons. This is fundamentally more expensive to compute; please don't specify > "uncompressed". > Taking the SHA512 of something less than 512 bits seemed wrong. > This appears incompatible with multisignature; which is unfortunate. > I agree. I could not find a straightforward way to express a multisignature payment code in less than 80 bytes. > I'm disappointed that there isn't any thought given to solving the > scanning privacy without forcing non-private pure-overhead messaging > transactions on heavily reused addresses. Are you aware of the IBE > approach that allows someone to request a third party scan for them > with block by block control over their delegation of scanning? > I suspect this is a case where we just can't have all the features we want. In this proposal I optimized for non-reliance on third party services and a guaranteed ability to recover spendable funds from a seed backup. Gaining those two features resulted in some tradeoffs as you noted, but I think there are enough benefits to make them worthwhile. In particular, payment codes could be the basis for a Heartbleed-free payment protocol that can positively identify customers and automatically provide refund capabilities in a merchant-customer relationship. A merchant only requires one payment code which they can safely use for all their customers, meaning they only ever need to associate 65 bytes with their identity to allow customers to make sure they are paying the right entity. Exchanges could restrict bitcoin withdrawals to a single payment code known to be associated with their identified customer. This would make thefts easier (without involving address reuse as in locking withdrawals to a single P2PKH address). In some jurisdictions the ability to prove that withdrawals are sent to a positively-identified party, rather than arbitrary third parties, might move some Bitcoin businesses out of money transmitter territory into less onerous regulatory situations. [-- Attachment #2: Type: text/html, Size: 5865 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
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* [Bitcoin-development] Fwd: Reusable payment codes [not found] ` <CAHabJ+Oabx80+_1KutfrPUt5QEnMivfNeeh4uJJJOsiHRQqSZw@mail.gmail.com> @ 2015-04-25 0:21 ` Justus Ranvier 0 siblings, 0 replies; 11+ messages in thread From: Justus Ranvier @ 2015-04-25 0:21 UTC (permalink / raw) To: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 4439 bytes --] I have pushed an updated version of the proposal which incorporates some of the received feedback and adds a note about the consequences of sharing a payment code-enabled walled on multiple devices: https://github.com/justusranvier/rfc/blob/payment_code/bips/bip-pc01.mediawiki https://github.com/justusranvier/rfc/commit/8c4d3429012eb15847c4ae68f212c8b2dcd1b521 On Sat, Apr 25, 2015 at 12:21 AM, Justus Ranvier <justus.ranvier@monetas•net > wrote: > > > On Fri, Apr 24, 2015 at 10:58 PM, Gregory Maxwell <gmaxwell@gmail•com> > wrote: > >> So this requires making dust payments to a constantly reused address >> in order to (ab)use the blockchain as a messaging layer. >> >> Indeed, this is more SPV compatible; but it seems likely to me that >> _in practice_ it would almost completely undermine the privacy the >> idea hoped to provide; because you'd have an observable linkage to a >> highly reused address. >> > > I agree that the output associated with notification transactions would > require special handling to avoid privacy leaks. At a minimum they'd > require mixing or being donated to miners as a transaction fee. > > >> >> It would also more than double the data sent for the application where >> 'stealth addresses' are most important: one-time anonymous donations >> (in other contexts; you have two way communication between the >> participants, and so you can just given them a one off address without >> singling in the public network.) >> > > Communication is only one way, except for the case in which the recipient > wants to send a refund. Assuming no refund and only a single anonymous > donation in the lifetime of the sender's identity, payment codes would > require 65 bytes vs 40 bytes for stealth addresses. > > As soon as the sender sends more than one donation to the same recipient, > payment codes show an space advantage over stealth addresses. > > This kind of binding was intentionally designed out of the stealth >> > address proposal; I think this scheme can be made to work without any >> increase in size by reusing the payment code as the ephemeral public >> key (or actually being substantially smaller e.g. use the shared >> secret as the chain code, but I should give it more thought) >> > > With 97 byte standard OP_RETURN values the ephemeral public > key could be appended to the chain code, but that's undesirable for other > reasons. > > This is fundamentally more expensive to compute; please don't specify >> "uncompressed". >> > > Taking the SHA512 of something less than 512 bits seemed wrong. > > >> This appears incompatible with multisignature; which is unfortunate. >> > > I agree. I could not find a straightforward way to express a > multisignature payment code in less than 80 bytes. > > >> I'm disappointed that there isn't any thought given to solving the >> scanning privacy without forcing non-private pure-overhead messaging >> transactions on heavily reused addresses. Are you aware of the IBE >> approach that allows someone to request a third party scan for them >> with block by block control over their delegation of scanning? >> > > I suspect this is a case where we just can't have all the features we want. > > In this proposal I optimized for non-reliance on third party services and > a guaranteed ability to recover spendable funds from a seed backup. > > Gaining those two features resulted in some tradeoffs as you noted, but I > think there are enough benefits to make them worthwhile. > > In particular, payment codes could be the basis for a Heartbleed-free > payment protocol that can positively identify customers and automatically > provide refund capabilities in a merchant-customer relationship. A merchant > only requires one payment code which they can safely use for all their > customers, meaning they only ever need to associate 65 bytes with their > identity to allow customers to make sure they are paying the right entity. > > Exchanges could restrict bitcoin withdrawals to a single payment code > known to be associated with their identified customer. This would make > thefts easier (without involving address reuse as in locking withdrawals to > a single P2PKH address). > > In some jurisdictions the ability to prove that withdrawals are sent to a > positively-identified party, rather than arbitrary third parties, might > move some Bitcoin businesses out of money transmitter territory into less > onerous regulatory situations. > > [-- Attachment #2: Type: text/html, Size: 6882 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
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* [Bitcoin-development] Fwd: Reusable payment codes [not found] ` <CAHabJ+NDqMN-rQ1BN1TfOjGLQHH-3Wd28LdoF95Agn4HdRrThg@mail.gmail.com> @ 2015-04-25 0:22 ` Justus Ranvier [not found] ` <CAAS2fgSAT2otym64oUACpWD8jWLAB6dBusONn-WUx2DK59SB5w@mail.gmail.com> 0 siblings, 1 reply; 11+ messages in thread From: Justus Ranvier @ 2015-04-25 0:22 UTC (permalink / raw) To: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 2897 bytes --] Taking the hash of the secret would then require an extra step to make sure the hash is valid for secp256k1. Using the x value directly avoids the need for that check. On Fri, Apr 24, 2015 at 10:35 PM, Patrick Mccorry (PGR) < patrick.mccorry@newcastle•ac.uk> wrote: > When computing the diffie Hellman secret - why do you choose the x > co-ordinate instead of the hash of the secret which is standard practice > for stealth addresses > > Sent from my iPhone > > On 24 Apr 2015, at 21:27, Justus Ranvier <justus.ranvier@monetas•net> > wrote: > > -----BEGIN PGP SIGNED MESSAGE----- > > Hash: SHA1 > > > > https://github.com/justusranvier/rfc/blob/payment_code/bips/bip-pc01.mediawiki > > > This link contains an RFC for a new type of Bitcoin address called a > "payment code" > > > Payment codes are SPV-friendly alternatives to DarkWallet-style stealth > addresses which provide useful features such as positively identifying > senders to recipients and automatically providing for transaction refunds. > > > Payment codes can be publicly advertised and associated with a real-life > identity without causing a loss of financial privacy. > > > Compared to stealth addresses, payment codes require less blockchain > data storage. > > > Payment codes require 65 bytes of OP_RETURN data per sender-recipient > pair, while stealth addresses require 40 bytes per transaction. > > > -----BEGIN PGP SIGNATURE----- > > Version: GnuPG v1 > > > iQIcBAEBAgAGBQJVOqCRAAoJECpf2nDq2eYjluEP/RVJk+miDIihY4ilIvUbKvMd > > JLLqHr7Q1dlZyMIG/UqVWdoP5hzg/16B+q2iAB9jXozPnrDp0mggBh6rIGroevAa > > Kqfrs+Rrog1w9auhd67LWORDqav6YIrjTJIxdLxe11IEiq5rWbHPNUEDMzdEmHbz > > QfTH7KWAP2BasO5ETXcfu6BcccrXZ3XOKLON2h3NGD/cEDizY+uT2k3QN54z+KxG > > NB9scKbzVvsJwkyBrgbV+As9H3k6PnFsojYgAaE9gkp7D2+ahjzUiOH5rv6TbbYR > > o2X5MOiTY2/YZEqZPG7IR03ZAgeLVCvXXysjPOfzUKbmTF4w849sm8BuhixzDXHo > > 2V/HHKoGclIohcODBCWi0tVQXshZt4QkCNJBW5o3nL6Nn2YOp6hmw8YKAHnw3E7h > > /wIgk5f+NOLl/iIxoAxAdavEj5P6N4ic+OB6MAjnhEilWfBvCIpqWLGNvrtOhEa9 > > EnPHcgb4ILBu4OionJhsNpJ/O95C0OEypMm25MIS+rQcV4Uxe5IOS2OuT/GreLET > > n/7Y0mJbqYbLBjVsfS+DNjvsgyJl5AxhcMrdVyXJjSYVcCoRhcoX5Ceidd+YkbHI > > OMs5f63tM1Rgi/WY4Ct80SD5EbULZuu8j1KJ9HPGuMt081JSBH+L5isiKuazPeO+ > > SGApMBd4Q89fKzL2djae > > =Dypr > > -----END PGP SIGNATURE----- > > > ------------------------------------------------------------------------------ > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable Insights > Deep dive visibility with transaction tracing using APM Insight. > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > > _______________________________________________ > Bitcoin-development mailing list > Bitcoin-development@lists•sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > > [-- Attachment #2: Type: text/html, Size: 4979 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
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* Re: [Bitcoin-development] Fwd: Reusable payment codes [not found] ` <CAAS2fgSAT2otym64oUACpWD8jWLAB6dBusONn-WUx2DK59SB5w@mail.gmail.com> @ 2015-04-25 2:34 ` Justus Ranvier 2015-04-26 12:58 ` Mike Hearn 0 siblings, 1 reply; 11+ messages in thread From: Justus Ranvier @ 2015-04-25 2:34 UTC (permalink / raw) To: Gregory Maxwell; +Cc: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 4938 bytes --] On Sat, Apr 25, 2015 at 3:30 AM, Gregory Maxwell <gmaxwell@gmail•com> wrote: > On Sat, Apr 25, 2015 at 12:22 AM, Justus Ranvier > <justus.ranvier@monetas•net> wrote: > > Taking the hash of the secret would then require an extra step to make > sure > > the hash is valid for secp256k1. > > The x value may not be a valid member of the group, effectively the > same as with a hash. Its also very unequally distributed, as only > about half the possible values are points on the curve. ack > > With 97 byte standard OP_RETURN values the ephemeral public > > key could be appended to the chain code, but that's undesirable for > other reasons. > > Can you elaborate? Storing a ~33 byte (deterministically generated) > ephemeral key should be all that is required. Everything else, > including the chain code could be derived from it. What reason do you > have to include additional data? > The goal of the notification transaction is to send the same payment code to every recipient, but obscure the identity of the sender of the notification transaction from third party blockchain observers. The shared secret is used for that purpose, and the sender's public key used for ECDH can't be one derived from the payment code since the recipient doesn't yet know the payment code. The notification transaction needs to communicate the 65 byte payment code along with one ephemeral public key used for ECDH. If that ephemeral key is not located in a signature script, it has to be somewhere else (such as in the same OP_RETURN output as the payment code.) > > Taking the SHA512 of something less than 512 bits seemed wrong. > > Why should it? Adding the Y does not increase the entropy at all. As > an aside, I think this can be reformulated to only need 256 bits of > output, and then the need for yet-another-hash-function could be > avoided in some cases. > Already fixed in https://github.com/justusranvier/rfc/commit/8c4d3429012eb15847c4ae68f212c8b2dcd1b521 but it would be good to get confirmation of whether the way I fixed it is valid. > In this proposal I optimized for non-reliance on third party services > > The requirement for inputs is a guaranteed dependency on third party > services; so if thats whats being optimized for here it must go (well, > I think it must go for the reason of avoiding blocking users from > using other schemes to control their coins too..). > I'm not sure what you mean by "the requirement for inputs is a guaranteed dependency on third party services" At the proposal currently stands, an SPV wallet will have no trouble sending or receiving notification transactions without access to a third party service. The recipient just needs to see the transactions associated with its notification address. The point about restricting the types of scripts used as inputs is valid, but I think workarounds are available. If nothing else, the sender can make a suitable input using it's own (suitably mixed) coins first. > I agree. I could not find a straightforward way to express a > multisignature payment code in less than 80 bytes. > > A prior stealth address proposal here handled them fine with only a > single ephemeral point in the op_return. It does result in a longer > address (is that what you're referring to with '80 bytes'?) > I considered defining an additional path level for deterministic m-of-n multisig and adding a few bytes to the payment code to express those parameters, but thought it would be too limiting since it would preclude multisig with truly independent keys. It is a thing that could be done, however. > Exchanges could restrict bitcoin withdrawals to a single payment code > known to be associated with their identified customer. > > In some jurisdictions the ability to prove that withdrawals are sent to > a positively-identified party, rather than arbitrary third parties, might > move some Bitcoin businesses out of money transmitter territory into less > onerous regulatory situations. > > But this mandates horrible key management practices, reliance on a > single "hardcoded" private key which you cannot change; even if it > might be compromised or lost to the wind. It's less horrible than > sticking to a single address because it doesn't wedge privacy, I > agree; but care should be taken that a tortured dance for confused > regulatory cargo-cult reasons doesn't mandate people not engage in > sound practices like periodic key rotation. :) > Cold storage is still available (if admittedly less convenient than in traditional wallets). I would expect exchanges in practice to allow for payment codes to be changed, just with non-trivial waiting periods and plenty of human overview. It would be an infrequent event compared to the frequency of withdrawals. Various schemes which use public key authentication instead of passwords for web site authentication could be used to continually verify that the user hasn't lost access to the key. [-- Attachment #2: Type: text/html, Size: 6968 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Bitcoin-development] Fwd: Reusable payment codes 2015-04-25 2:34 ` Justus Ranvier @ 2015-04-26 12:58 ` Mike Hearn 2015-04-26 14:50 ` Justus Ranvier 0 siblings, 1 reply; 11+ messages in thread From: Mike Hearn @ 2015-04-26 12:58 UTC (permalink / raw) To: Justus Ranvier; +Cc: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 158 bytes --] Could you maybe write a short bit of text comparing this approach to extending BIP70 and combining it with a simple Subspace style store-and-forward network? [-- Attachment #2: Type: text/html, Size: 210 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Bitcoin-development] Fwd: Reusable payment codes 2015-04-26 12:58 ` Mike Hearn @ 2015-04-26 14:50 ` Justus Ranvier 0 siblings, 0 replies; 11+ messages in thread From: Justus Ranvier @ 2015-04-26 14:50 UTC (permalink / raw) To: Mike Hearn; +Cc: Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 787 bytes --] Payment codes establish the identity of the payer and allow for simpler methods for identifying the payee, and automatically provide the payee with the information they need to send a refund. If merchants and customers were using payment codes, they would not need the BIP70 equivalents. I think the best way to explain payment codes is that they add the missing "from address" to transactions which users want, but we've had to tell them they can't have. A payment code behaves much more like an email address than a traditional Bitcoin address. On Sun, Apr 26, 2015 at 2:58 PM, Mike Hearn <mike@plan99•net> wrote: > Could you maybe write a short bit of text comparing this approach to > extending BIP70 and combining it with a simple Subspace style > store-and-forward network? > [-- Attachment #2: Type: text/html, Size: 1158 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Bitcoin-development] Reusable payment codes 2015-04-24 20:00 [Bitcoin-development] Reusable payment codes Justus Ranvier 2015-04-24 20:58 ` Gregory Maxwell [not found] ` <1AE7B0A2-90EE-42EE-9D30-4DC1B5892E53@newcastle.ac.uk> @ 2015-06-16 16:26 ` odinn 2015-06-16 17:46 ` Peter Todd 2 siblings, 1 reply; 11+ messages in thread From: odinn @ 2015-06-16 16:26 UTC (permalink / raw) To: Justus Ranvier, Bitcoin Dev -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 This is very well done. Have you seen this discussion that I started regarding BIP 63? https://bitcointalk.org/index.php?topic=1083961.0 I have no response from Peter Todd back on it other than "my time is better spent focusing on more fundemental issues" and "I've also got no-one interested in funding stealth address development right now," when several people (myself included) offered to send donations to see the BIP (63) advance, no donation address was posted, so... waiting for him to act on that. I'm definitely supportive of seeing what you've written up here as Reusable payment codes move to draft in https://github.com/bitcoin/bips When you can, please write up something on bitcointalk as well. On 04/24/2015 01:00 PM, Justus Ranvier wrote: > Hash: SHA1 > > > https://github.com/justusranvier/rfc/blob/payment_code/bips/bip-pc01.m ediawiki > > > > This link contains an RFC for a new type of Bitcoin address called > a "payment code" > > > Payment codes are SPV-friendly alternatives to DarkWallet-style > stealth addresses which provide useful features such as positively > identifying senders to recipients and automatically providing for > transaction refunds. > > > Payment codes can be publicly advertised and associated with a > real-life identity without causing a loss of financial privacy. > > > Compared to stealth addresses, payment codes require less > blockchain data storage. > > > Payment codes require 65 bytes of OP_RETURN data per > sender-recipient pair, while stealth addresses require 40 bytes per > transaction. > > > > > > ---------------------------------------------------------------------- - -------- > > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable > Insights Deep dive visibility with transaction tracing using APM > Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > > > > _______________________________________________ Bitcoin-development > mailing list Bitcoin-development@lists•sourceforge.net > https://lists.sourceforge.net/lists/listinfo/bitcoin-development > - -- http://abis.io ~ "a protocol concept to enable decentralization and expansion of a giving economy, and a new social good" https://keybase.io/odinn -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJVgE4fAAoJEGxwq/inSG8CjgkH/i0aX4aJaOjrbI2xzWbPeL1T /APSvSqV0D610ljbw/MuRRFVagnK3lCs73fYolKw9uFG0cnwhIWJ53mCqPWhM5nL kIejDTHr9jQ2tbXrU2L481Oat1Z6vtdQj7LolXFfD3Ktqz+sqp//gBaC9EEZ5nOq 4oz71Am58pf8+XGhtJk0+4XDXzFNd71bKKY+nMf9f3bwqNX93jHiF48hXwijFPC4 MOZmYRh3Sf5LAVP5p1JY3aJRQv4M/W0L2RDC+GW8Ol997etQSGGLhESihNNPw1m8 GEqJLBmUBkavzsRpZ009czfzL7EiCwsMbOrVw918o2Y9NnVpY9a9cBNB+UJgCmk= =wAGz -----END PGP SIGNATURE----- ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Bitcoin-development] Reusable payment codes 2015-06-16 16:26 ` [Bitcoin-development] " odinn @ 2015-06-16 17:46 ` Peter Todd 2015-06-17 5:34 ` odinn 0 siblings, 1 reply; 11+ messages in thread From: Peter Todd @ 2015-06-16 17:46 UTC (permalink / raw) To: odinn; +Cc: Justus Ranvier, Bitcoin Dev [-- Attachment #1: Type: text/plain, Size: 1050 bytes --] On Tue, Jun 16, 2015 at 09:26:07AM -0700, odinn wrote: > This is very well done. > > Have you seen this discussion that I started regarding BIP 63? > > https://bitcointalk.org/index.php?topic=1083961.0 > > I have no response from Peter Todd back on it other than "my time is > better spent focusing on more fundemental issues" and "I've also got > no-one interested in funding stealth address development right now," > when several people (myself included) offered to send donations to see > the BIP (63) advance, no donation address was posted, so... waiting > for him to act on that. Sorry, but I'm looking at the huge amount of work that I'll likely have responding to the blocksize issue, so I think I'm inclined to shelve work on BIP63 for now. Feel free to take it up; a (>=2)-part standard describing the resuable codes aspect, and separately how the ephemeral key is transmitted to the recipient makes sense to me. -- 'peter'[:-1]@petertodd.org 0000000000000000127ab1d576dc851f374424f1269c4700ccaba2c42d97e778 [-- Attachment #2: Digital signature --] [-- Type: application/pgp-signature, Size: 650 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [Bitcoin-development] Reusable payment codes 2015-06-16 17:46 ` Peter Todd @ 2015-06-17 5:34 ` odinn 0 siblings, 0 replies; 11+ messages in thread From: odinn @ 2015-06-17 5:34 UTC (permalink / raw) To: Peter Todd; +Cc: Justus Ranvier, Bitcoin Dev -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Peter, my response below On 06/16/2015 10:46 AM, Peter Todd wrote: > On Tue, Jun 16, 2015 at 09:26:07AM -0700, odinn wrote: >> This is very well done. >> >> Have you seen this discussion that I started regarding BIP 63? >> >> https://bitcointalk.org/index.php?topic=1083961.0 >> >> I have no response from Peter Todd back on it other than "my time is >> better spent focusing on more fundemental issues" and "I've also got >> no-one interested in funding stealth address development right now," >> when several people (myself included) offered to send donations to se e >> the BIP (63) advance, no donation address was posted, so... waiting >> for him to act on that. > > Sorry, but I'm looking at the huge amount of work that I'll likely hav e > responding to the blocksize issue, so I think I'm inclined to shelve > work on BIP63 for now. I seriously find this pretty sad... you said that paying rent was an issue and your time was better spent on "more fundamental issues..." but the very least you could do is post a donation address... Is there someone who was working with you closely on the concept who could take it up since you are not going to be working on it? > > Feel free to take it up; a (>=2)-part standard describing the resuable > codes aspect, and separately how the ephemeral key is transmitted to t he > recipient makes sense to me. > I don't want to camp on Justus's thread on reusable payment codes ~ but on the subject of BIP 63, it just did make sense to mention... so if someone does have interest in working on it... please go to https://bitcointalk.org/index.php?topic=1083961.0 and reply there. - -- http://abis.io ~ "a protocol concept to enable decentralization and expansion of a giving economy, and a new social good" https://keybase.io/odinn -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQEcBAEBAgAGBQJVgQbMAAoJEGxwq/inSG8CD8gH/3jV+mLO9qv3t6JFxIvLMPtr slGbymQtuqfAC09b6ybx3p6u9I1o1Nb3IgK1riu/Z3AzHxlnuYVUxN3N5ns0zGnx F2WXs2suEa20YJkQ6dxZWLdNBjnUIEGGgXAit8X21LqVsqPfeZcocOWSeRDlePhk /HRFLVtMehqfqjbuFAaAewVZUyT4Bn+3IU74krqR3e3YA00/ym1C5xCE3/kHvKIL UF8EW9GgVYKuoyQdH3ICDwjiudwPOwIC4Ry0huaJgla43122RkwqYB+5kVr1583u dx3VW8vW8HyQZJF+vb8d3F57R6FC6zYtFhCe0IzDIh+6xQxStk5zosMNIrtPKp4= =h8Ib -----END PGP SIGNATURE----- ^ permalink raw reply [flat|nested] 11+ messages in thread
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2015-04-24 20:00 [Bitcoin-development] Reusable payment codes Justus Ranvier
2015-04-24 20:58 ` Gregory Maxwell
[not found] ` <CAHabJ+MtWJS=e3tkGih=xoP4ARgHe8X=D_p9OWTnRJi0z9epBw@mail.gmail.com>
2015-04-25 0:20 ` [Bitcoin-development] Fwd: " Justus Ranvier
[not found] ` <CAHabJ+Oabx80+_1KutfrPUt5QEnMivfNeeh4uJJJOsiHRQqSZw@mail.gmail.com>
2015-04-25 0:21 ` Justus Ranvier
[not found] ` <1AE7B0A2-90EE-42EE-9D30-4DC1B5892E53@newcastle.ac.uk>
[not found] ` <CAHabJ+NDqMN-rQ1BN1TfOjGLQHH-3Wd28LdoF95Agn4HdRrThg@mail.gmail.com>
2015-04-25 0:22 ` Justus Ranvier
[not found] ` <CAAS2fgSAT2otym64oUACpWD8jWLAB6dBusONn-WUx2DK59SB5w@mail.gmail.com>
2015-04-25 2:34 ` Justus Ranvier
2015-04-26 12:58 ` Mike Hearn
2015-04-26 14:50 ` Justus Ranvier
2015-06-16 16:26 ` [Bitcoin-development] " odinn
2015-06-16 17:46 ` Peter Todd
2015-06-17 5:34 ` odinn
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