joshua/dash-docs
1
0
Fork 0
mirror of https://github.com/seigler/dash-docs synced 2025-07-27 09:46:12 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions

Guide - update contracts section

Browse source
This commit is contained in:
thephez 2017-11-14 16:06:16 -05:00
parent 57bbb02486
commit 350ccce28f
2 changed files with 44 additions and 40 deletions
Download patch file Download diff file Expand all files Collapse all files

77
_includes/devdoc/guide_contracts.md
View file

@ -9,14 +9,13 @@ http://opensource.org/licenses/MIT.
{% autocrossref %} {% autocrossref %}
Contracts are Contracts are transactions which use the decentralized Dash system to enforce
transactions which use the decentralized Bitcoin system to enforce financial financial agreements.
agreements. Dash contracts can often be crafted to minimize dependency on outside
Bitcoin contracts can often be crafted to minimize dependency on outside
agents, such as the court system, which significantly decreases the risk agents, such as the court system, which significantly decreases the risk
of dealing with unknown entities in financial transactions. of dealing with unknown entities in financial transactions.
The following subsections will describe a variety of Bitcoin contracts The following subsections will describe a variety of Dash contracts
already in use. Because contracts deal with real people, not just already in use. Because contracts deal with real people, not just
transactions, they are framed below in story format. transactions, they are framed below in story format.
@ -35,18 +34,18 @@ Charlie-the-customer wants to buy a product from Bob-the-businessman,
but neither of them trusts the other person, so they use a contract to but neither of them trusts the other person, so they use a contract to
help ensure Charlie gets his merchandise and Bob gets his payment. help ensure Charlie gets his merchandise and Bob gets his payment.
A simple contract could say that Charlie will spend satoshis to an A simple contract could say that Charlie will spend duffs to an
output which can only be spent if Charlie and Bob both sign the input output which can only be spent if Charlie and Bob both sign the input
spending it. That means Bob won't get paid unless Charlie gets his spending it. That means Bob won't get paid unless Charlie gets his
merchandise, but Charlie can't get the merchandise and keep his payment. merchandise, but Charlie can't get the merchandise and keep his payment.
This simple contract isn't much help if there's a dispute, so Bob and This simple contract isn't much help if there's a dispute, so Bob and
Charlie enlist the help of Alice-the-arbitrator to create an [escrow Charlie enlist the help of Alice-the-arbitrator to create an [escrow
contract][/en/glossary/escrow-contract]{:#term-escrow-contract}{:.term}. Charlie spends his satoshis contract][/en/glossary/escrow-contract]{:#term-escrow-contract}{:.term}. Charlie spends his duffs
to an output which can only be spent if two of the three people sign the to an output which can only be spent if two of the three people sign the
input. Now Charlie can pay Bob if everything is ok, Bob can refund input. Now Charlie can pay Bob if everything is ok, Bob can refund
Charlie's money if there's a problem, or Alice can arbitrate and decide Charlie's money if there's a problem, or Alice can arbitrate and decide
who should get the satoshis if there's a dispute. who should get the duffs if there's a dispute.
To create a multiple-signature ([multisig][/en/glossary/multisig]{:#term-multisig}{:.term}) To create a multiple-signature ([multisig][/en/glossary/multisig]{:#term-multisig}{:.term})
output, they each give the others a public key. Then Bob creates the output, they each give the others a public key. Then Bob creates the
@ -72,7 +71,7 @@ keys provided).
Bob gives the redeem script to Charlie, who checks to make sure his Bob gives the redeem script to Charlie, who checks to make sure his
public key and Alice's public key are included. Then he hashes the public key and Alice's public key are included. Then he hashes the
redeem script to create a P2SH redeem script and pays the satoshis to it. Bob redeem script to create a P2SH redeem script and pays the duffs to it. Bob
sees the payment get added to the block chain and ships the merchandise. sees the payment get added to the block chain and ships the merchandise.
Unfortunately, the merchandise gets slightly damaged in transit. Charlie Unfortunately, the merchandise gets slightly damaged in transit. Charlie
@ -83,7 +82,7 @@ Charlie checked.
After looking at the evidence, Alice thinks a 40% refund is sufficient, After looking at the evidence, Alice thinks a 40% refund is sufficient,
so she creates and signs a transaction with two outputs, one that spends 60% so she creates and signs a transaction with two outputs, one that spends 60%
of the satoshis to Bob's public key and one that spends the remaining of the duffs to Bob's public key and one that spends the remaining
40% to Charlie's public key. 40% to Charlie's public key.
In the signature script Alice puts her signature In the signature script Alice puts her signature
@ -116,14 +115,16 @@ validates, the two transaction outputs show up in Bob's and Charlie's
wallets as spendable balances. wallets as spendable balances.
However, if Alice created and signed a transaction neither of them would However, if Alice created and signed a transaction neither of them would
agree to, such as spending all the satoshis to herself, Bob and Charlie agree to, such as spending all the duffs to herself, Bob and Charlie
can find a new arbitrator and sign a transaction spending the satoshis can find a new arbitrator and sign a transaction spending the duffs
to another 2-of-3 multisig redeem script hash, this one including a public to another 2-of-3 multisig redeem script hash, this one including a public
key from that second arbitrator. This means that Bob and Charlie never key from that second arbitrator. This means that Bob and Charlie never
need to worry about their arbitrator stealing their money. need to worry about their arbitrator stealing their money.
<!--
**Resource:** [BitRated](https://www.bitrated.com/) provides a multisig arbitration **Resource:** [BitRated](https://www.bitrated.com/) provides a multisig arbitration
service interface using HTML/JavaScript on a GNU AGPL-licensed website. service interface using HTML/JavaScript on a GNU AGPL-licensed website.
-->
{% endautocrossref %} {% endautocrossref %}
@ -140,18 +141,18 @@ someone posts to Bob's busy forum, Alice skims the post to make sure it
isn't offensive or spam. Alas, Bob often forgets to pay her, so Alice isn't offensive or spam. Alas, Bob often forgets to pay her, so Alice
demands to be paid immediately after each post she approves or rejects. demands to be paid immediately after each post she approves or rejects.
Bob says he can't do that because hundreds of small payments will cost Bob says he can't do that because hundreds of small payments will cost
him thousands of satoshis in transaction fees, so Alice suggests they use a him thousands of duffs in transaction fees, so Alice suggests they use a
[micropayment channel][]{:#term-micropayment-channel}{:.term}. [micropayment channel][]{:#term-micropayment-channel}{:.term}.
Bob asks Alice for her public key and then creates two transactions. Bob asks Alice for her public key and then creates two transactions.
The first transaction pays 100 millibitcoins to a P2SH output whose The first transaction pays 100 millidash to a P2SH output whose
2-of-2 multisig redeem script requires signatures from both Alice and Bob. 2-of-2 multisig redeem script requires signatures from both Alice and Bob.
This is the bond transaction. This is the bond transaction.
Broadcasting this transaction would let Alice hold the millibitcoins Broadcasting this transaction would let Alice hold the millidash
hostage, so Bob keeps this transaction private for now and creates a hostage, so Bob keeps this transaction private for now and creates a
second transaction. second transaction.
The second transaction spends all of the first transaction's millibitcoins The second transaction spends all of the first transaction's millidash
(minus a transaction fee) back to Bob after a 24 hour delay enforced (minus a transaction fee) back to Bob after a 24 hour delay enforced
by locktime. This is the refund transaction. Bob can't sign the refund transaction by himself, so he gives by locktime. This is the refund transaction. Bob can't sign the refund transaction by himself, so he gives
it to Alice to sign, as shown in the it to Alice to sign, as shown in the
@ -164,7 +165,7 @@ future, signs it, and gives a copy of it back to Bob. She then asks Bob
for the bond transaction and checks that the refund transaction spends for the bond transaction and checks that the refund transaction spends
the output of the bond transaction. She can now broadcast the bond the output of the bond transaction. She can now broadcast the bond
transaction to the network to ensure Bob has to wait for the time lock transaction to the network to ensure Bob has to wait for the time lock
to expire before further spending his millibitcoins. Bob hasn't actually to expire before further spending his millidash. Bob hasn't actually
spent anything so far, except possibly a small transaction fee, and spent anything so far, except possibly a small transaction fee, and
he'll be able to broadcast the refund transaction in 24 hours for a he'll be able to broadcast the refund transaction in 24 hours for a
full refund. full refund.
@ -190,21 +191,22 @@ near the time lock expiry, she could be cheated out of her payment.
Transaction malleability, discussed above in the Transactions section, Transaction malleability, discussed above in the Transactions section,
is another reason to limit the value of micropayment channels. is another reason to limit the value of micropayment channels.
If someone uses transaction malleability to break the link between the If someone uses transaction malleability to break the link between the
two transactions, Alice could hold Bob's 100 millibitcoins hostage even if she two transactions, Alice could hold Bob's 100 millidash hostage even if she
hadn't done any work. hadn't done any work.
For larger payments, Bitcoin transaction fees are very low as a For larger payments, Dash transaction fees are very low as a
percentage of the total transaction value, so it makes more sense to percentage of the total transaction value, so it makes more sense to
protect payments with immediately-broadcast separate transactions. protect payments with immediately-broadcast separate transactions.
**Resource:** The [bitcoinj][] Java library **Resource:** The [dashj][] Java library
provides a complete set of micropayment functions, an example provides a complete set of micropayment functions, an example
implementation, and [a implementation, and [a
tutorial][bitcoinj micropayment tutorial] tutorial (from bitcoinj)][bitcoinj micropayment tutorial]
all under an Apache license. all under an Apache license.
{% endautocrossref %} {% endautocrossref %}
<!-- Obsolesced by PrivateSend
### CoinJoin ### CoinJoin
{% include helpers/subhead-links.md %} {% include helpers/subhead-links.md %}
@ -212,28 +214,28 @@ all under an Apache license.
Alice is concerned about her privacy. She knows every transaction gets Alice is concerned about her privacy. She knows every transaction gets
added to the public block chain, so when Bob and Charlie pay her, they added to the public block chain, so when Bob and Charlie pay her, they
can each easily track those satoshis to learn what Bitcoin can each easily track those duffs to learn what Bitcoin
addresses she pays, how much she pays them, and possibly how many addresses she pays, how much she pays them, and possibly how many
satoshis she has left. duffs she has left.
Alice isn't a criminal, she just wants plausible deniability about Alice isn't a criminal, she just wants plausible deniability about
where she has spent her satoshis and how many she has left, so she where she has spent her duffs and how many she has left, so she
starts up the Tor anonymity service on her computer and logs into an starts up the Tor anonymity service on her computer and logs into an
IRC chatroom as "AnonGirl." IRC chatroom as "AnonGirl."
Also in the chatroom are "Nemo" and "Neminem." They collectively Also in the chatroom are "Nemo" and "Neminem." They collectively
agree to transfer satoshis between each other so no one besides them agree to transfer duffs between each other so no one besides them
can reliably determine who controls which satoshis. But they're faced can reliably determine who controls which duffs. But they're faced
with a dilemma: who transfers their satoshis to one of the other two with a dilemma: who transfers their duffs to one of the other two
pseudonymous persons first? The CoinJoin-style contract, shown in the pseudonymous persons first? The CoinJoin-style contract, shown in the
illustration below, makes this decision easy: they create a single illustration below, makes this decision easy: they create a single
transaction which does all of the spending simultaneously, ensuring none transaction which does all of the spending simultaneously, ensuring none
of them can steal the others' satoshis. of them can steal the others' duffs.
![Example CoinJoin Transaction](/img/dev/en-coinjoin.svg) ![Example CoinJoin Transaction](/img/dev/en-coinjoin.svg)
Each contributor looks through their collection of Unspent Transaction Each contributor looks through their collection of Unspent Transaction
Outputs (UTXOs) for 100 millibitcoins they can spend. They then each generate Outputs (UTXOs) for 100 millidash they can spend. They then each generate
a brand new public key and give UTXO details and pubkey hashes to the a brand new public key and give UTXO details and pubkey hashes to the
facilitator. In this case, the facilitator is AnonGirl; she creates facilitator. In this case, the facilitator is AnonGirl; she creates
a transaction spending each of the UTXOs to three equally-sized outputs. a transaction spending each of the UTXOs to three equally-sized outputs.
@ -243,7 +245,7 @@ AnonGirl then signs her inputs using `SIGHASH_ALL` to ensure nobody can
change the input or output details. She gives the partially-signed change the input or output details. She gives the partially-signed
transaction to Nemo who signs his inputs the same way and passes it transaction to Nemo who signs his inputs the same way and passes it
to Neminem, who also signs it the same way. Neminem then broadcasts to Neminem, who also signs it the same way. Neminem then broadcasts
the transaction to the peer-to-peer network, mixing all of the millibitcoins in the transaction to the peer-to-peer network, mixing all of the millidash in
a single transaction. a single transaction.
As you can see in the illustration, there's no way for anyone besides As you can see in the illustration, there's no way for anyone besides
@ -257,19 +259,19 @@ Neminem. If Alice does a few more CoinJoins, Bob and Charlie might
have to guess which transactions made by dozens or hundreds of people have to guess which transactions made by dozens or hundreds of people
were actually made by Alice. were actually made by Alice.
The complete history of Alice's satoshis is still in the block chain, The complete history of Alice's duffs is still in the block chain,
so a determined investigator could talk to the people AnonGirl so a determined investigator could talk to the people AnonGirl
CoinJoined with to find out the ultimate origin of her satoshis and CoinJoined with to find out the ultimate origin of her duffs and
possibly reveal AnonGirl as Alice. But against anyone casually browsing possibly reveal AnonGirl as Alice. But against anyone casually browsing
block chain history, Alice gains plausible deniability. block chain history, Alice gains plausible deniability.
The CoinJoin technique described above costs the participants a small The CoinJoin technique described above costs the participants a small
amount of satoshis to pay the transaction fee. An alternative amount of duffs to pay the transaction fee. An alternative
technique, purchaser CoinJoin, can actually save them satoshis and technique, purchaser CoinJoin, can actually save them duffs and
improve their privacy at the same time. improve their privacy at the same time.
AnonGirl waits in the IRC chatroom until she wants to make a purchase. AnonGirl waits in the IRC chatroom until she wants to make a purchase.
She announces her intention to spend satoshis and waits until someone She announces her intention to spend duffs and waits until someone
else wants to make a purchase, likely from a different merchant. Then else wants to make a purchase, likely from a different merchant. Then
they combine their inputs the same way as before but set the outputs they combine their inputs the same way as before but set the outputs
to the separate merchant addresses so nobody will be able to figure to the separate merchant addresses so nobody will be able to figure
@ -280,10 +282,11 @@ Since they would've had to pay a transaction fee to make their purchases
anyway, AnonGirl and her co-spenders don't pay anything extra---but anyway, AnonGirl and her co-spenders don't pay anything extra---but
because they reduced overhead by combining multiple transactions, saving because they reduced overhead by combining multiple transactions, saving
bytes, they may be able to pay a smaller aggregate transaction fee, bytes, they may be able to pay a smaller aggregate transaction fee,
saving each one of them a tiny amount of satoshis. saving each one of them a tiny amount of duffs.
**Resource:** An alpha-quality (as of this writing) implementation of decentralized **Resource:** An alpha-quality (as of this writing) implementation of decentralized
CoinJoin is [CoinMux](http://coinmux.com/), available under the Apache CoinJoin is [CoinMux](http://coinmux.com/), available under the Apache
license. license.
-->
{% endautocrossref %} {% endautocrossref %}

1
_includes/references.md
View file

@ -455,6 +455,7 @@ http://opensource.org/licenses/MIT.
[core paymentrequest.proto]: https://github.com/dashpay/dash/blob/master/src/qt/paymentrequest.proto [core paymentrequest.proto]: https://github.com/dashpay/dash/blob/master/src/qt/paymentrequest.proto
[core script.h]: https://github.com/dashpay/dash/blob/master/src/script/script.h [core script.h]: https://github.com/dashpay/dash/blob/master/src/script/script.h
[creative commons attribution 3.0 license]: https://creativecommons.org/licenses/by/3.0/ [creative commons attribution 3.0 license]: https://creativecommons.org/licenses/by/3.0/
[DashJ]: https://github.com/HashEngineering/dashj
[DER]: https://en.wikipedia.org/wiki/X.690#DER_encoding [DER]: https://en.wikipedia.org/wiki/X.690#DER_encoding
[dig command]: https://en.wikipedia.org/wiki/Dig_%28Unix_command%29 [dig command]: https://en.wikipedia.org/wiki/Dig_%28Unix_command%29
[DNS A records]: http://tools.ietf.org/html/rfc1035#section-3.2.2 [DNS A records]: http://tools.ietf.org/html/rfc1035#section-3.2.2