mirror of
https://github.com/bitcoinbook/bitcoinbook
synced 2024-11-25 17:38:26 +00:00
105 lines
3.7 KiB
Plaintext
105 lines
3.7 KiB
Plaintext
--------------------------------------------------
|
||
BIP: 13
|
||
Title: Address Format for pay-to-script-hash
|
||
Author: Gavin Andresen <gavinandresen@gmail.com>
|
||
Status: Final
|
||
Type: Standards Track
|
||
Created: 2011-10-18
|
||
--------------------------------------------------
|
||
|
||
[[abstract]]
|
||
Abstract
|
||
~~~~~~~~
|
||
|
||
This BIP describes a new type of Bitcoin address to support arbitrarily
|
||
complex transactions. Complexity in this context is defined as what
|
||
information is needed by the recipient to respend the received coins, in
|
||
contrast to needing a single ECDSA private key as in current
|
||
implementations of Bitcoin.
|
||
|
||
In essence, an address encoded under this proposal represents the
|
||
encoded hash of a script, rather than the encoded hash of an ECDSA
|
||
public key.
|
||
|
||
[[motivation]]
|
||
Motivation
|
||
~~~~~~~~~~
|
||
|
||
Enable "end-to-end" secure wallets and payments to fund escrow
|
||
transactions or other complex transactions. Enable third-party wallet
|
||
security services.
|
||
|
||
[[specification]]
|
||
Specification
|
||
~~~~~~~~~~~~~
|
||
|
||
The new bitcoin address type is constructed in the same manner as
|
||
existing bitcoin addresses (see link:Base58Check encoding[Base58Check
|
||
encoding]):
|
||
|
||
` base58-encode: [one-byte version][20-byte hash][4-byte checksum]`
|
||
|
||
Version byte is 5 for a main-network address, 196 for a testnet address.
|
||
The 20-byte hash is the hash of the script that will be used to redeem
|
||
the coins. And the 4-byte checksum is the first four bytes of the double
|
||
SHA256 hash of the version and hash.
|
||
|
||
[[rationale]]
|
||
Rationale
|
||
~~~~~~~~~
|
||
|
||
One criticism is that bitcoin addresses should be deprecated in favor of
|
||
a more user-friendly mechanism for payments, and that this will just
|
||
encourage continued use of a poorly designed mechanism.
|
||
|
||
Another criticism is that bitcoin addresses are inherently insecure
|
||
because there is no identity information tied to them; if you only have
|
||
a bitcoin address, how can you be certain that you're paying who or what
|
||
you think you're paying?
|
||
|
||
Furthermore, truncating SHA256 is not an optimal checksum; there are
|
||
much better error-detecting algorithms. If we are introducing a new form
|
||
of Bitcoin address, then perhaps a better algorithm should be used.
|
||
|
||
This is one piece of the simplest path to a more secure bitcoin
|
||
infrastructure. It is not intended to solve all of bitcoin's usability
|
||
or security issues, but to be an incremental improvement over what
|
||
exists today. A future BIP or BIPs should propose more user-friendly
|
||
mechanisms for making payments, or for verifying that you're sending a
|
||
payment to the Free Software Foundation and not Joe Random Hacker.
|
||
|
||
Assuming that typing in bitcoin addresses manually will become
|
||
increasingly rare in the future, and given that the existing checksum
|
||
method for bitcoin addresses seems to work "well enough" in practice and
|
||
has already been implemented multiple times, the Author believes no
|
||
change to the checksum algorithm is necessary.
|
||
|
||
The leading version bytes are chosen so that, after base58 encoding, the
|
||
leading character is consistent: for the main network, byte 5 becomes
|
||
the character '3'. For the testnet, byte 196 is encoded into '2'.
|
||
|
||
[[backwards-compatibility]]
|
||
Backwards Compatibility
|
||
~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
||
This proposal is not backwards compatible, but it fails gracefully-- if
|
||
an older implementation is given one of these new bitcoin addresses, it
|
||
will report the address as invalid and will refuse to create a
|
||
transaction.
|
||
|
||
[[reference-implementation]]
|
||
Reference Implementation
|
||
~~~~~~~~~~~~~~~~~~~~~~~~
|
||
|
||
See base58.cpp1/base58.h at https://github.com/bitcoin/bitcoin/src
|
||
|
||
[[see-also]]
|
||
See Also
|
||
~~~~~~~~
|
||
|
||
* link:bip-0012.mediawiki[BIP 12: OP_EVAL, the original P2SH design]
|
||
* link:bip-0016.mediawiki[BIP 16: Pay to Script Hash (aka "/P2SH/")]
|
||
* link:bip-0017.mediawiki[BIP 17: OP_CHECKHASHVERIFY, another P2SH
|
||
design]
|
||
|