Without the protocol amendment introduced by this commit, an NFT ID can
be reminted in this manner:
1. Alice creates an account and mints an NFT.
2. Alice burns the NFT with an `NFTokenBurn` transaction.
3. Alice deletes her account with an `AccountDelete` transaction.
4. Alice re-creates her account.
5. Alice mints an NFT with an `NFTokenMint` transaction with params:
`NFTokenTaxon` = 0, `Flags` = 9).
This will mint a NFT with the same `NFTokenID` as the one minted in step
1. The params that construct the NFT ID will cause a collision in
`NFTokenID` if their values are equal before and after the remint.
With the `fixNFTokenRemint` amendment, there is a new sequence number
construct which avoids this scenario:
- A new `AccountRoot` field, `FirstNFTSequence`, stays constant over
time.
- This field is set to the current account sequence when the account
issues their first NFT.
- Otherwise, it is not set.
- The sequence of a newly-minted NFT is computed by: `FirstNFTSequence +
MintedNFTokens`.
- `MintedNFTokens` is then incremented by 1 for each mint.
Furthermore, there is a new account deletion restriction:
- An account can only be deleted if `FirstNFTSequence + MintedNFTokens +
256` is less than the current ledger sequence.
- 256 was chosen because it already exists in the current account
deletion constraint.
Without this restriction, an NFT may still be remintable. Example
scenario:
1. Alice's account sequence is at 1.
2. Bob is Alice's authorized minter.
3. Bob mints 500 NFTs for Alice. The NFTs will have sequences 1-501, as
NFT sequence is computed by `FirstNFTokenSequence + MintedNFTokens`).
4. Alice deletes her account at ledger 257 (as required by the existing
`AccountDelete` amendment).
5. Alice re-creates her account at ledger 258.
6. Alice mints an NFT. `FirstNFTokenSequence` initializes to her account
sequence (258), and `MintedNFTokens` initializes as 0. This
newly-minted NFT would have a sequence number of 258, which is a
duplicate of what she issued through authorized minting before she
deleted her account.
---------
Signed-off-by: Shawn Xie <shawnxie920@gmail.com>
* Introduces amendment `XRPFees`
* Convert fee voting and protocol messages to use XRPAmounts
* Includes Validations, Change transactions, the "Fees" ledger object,
and subscription messages
* Improve handling of 0 drop reference fee with TxQ. For use with networks that do not want to require fees
* Note that fee escalation logic is still in place, which may cause the
open ledger fee to rise if the network is busy. 0 drop transactions
will still queue, and fee escalation can be effectively disabled by
modifying the configuration on all nodes
* Change default network reserves to match Mainnet
* Name the new SFields *Drops (not *XRP)
* Reserve SField IDs for Hooks
* Clarify comments explaining the ttFEE transaction field validation
In order to preserve the Hooks ABI, it is important that field
values used for hooks be stable going forward.
This commit reserves the required codes so that they will not
be repurposed before Hooks can be proposed for inclusion in
the codebase.
There have been cases in the past where SFields have been defined
in such a way that they did not follow our conventions. In
particular, the string representation of an SField should match
the in-code name of the SField.
This change leverages the preprocessor to encourage SFields to
be properly constructed.
The suffixes of SField types are changed to be the same as
the suffixes of corresponding SerializedTypeIDs. This allows
The preprocessor to match types using simple name pasting.
Since the string representation of the SField is part of our
stable API, the name of sfPayChannel was changed to sfChannel.
This change allows sfChannel to follow our conventions while
making no changes to our external API.
Tickets are a mechanism to allow for the "out-of-order" execution of
transactions on the XRP Ledger.
This commit, if merged, reworks the existing support for tickets and
introduces support for 'ticket batching', completing the feature set
needed for tickets.
The code is gated under the newly-introduced `TicketBatch` amendment
and the `Tickets` amendment, which is not presently active on the
network, is being removed.
The specification for this change can be found at:
https://github.com/xrp-community/standards-drafts/issues/16
This change can help improve the liveness of the network during periods of network
instability, by allowing the network to track which validators are presently not online
and to disregard them for the purposes of quorum calculations.
Currently there is no mechanism for a validator to report the
version of the software it is currently running. Such reports
can be useful for those who are developing network monitoring
dashboards and server operators in general.
This commit, if merged, defines an encoding scheme to encode
a version string into a 64-bit unsigned integer and adds an
additional optional field to validations.
This commit piggybacks on "HardenedValidations" amendment to
determine whether version information should be propagated
or not.
The general encoding scheme is:
XXXXXXXX-XXXXXXXX-YYYYYYYY-YYYYYYYY-YYYYYYYY-YYYYYYYY-YYYYYYYY-YYYYYYYY
X: 16 bits identifying the particular implementation
Y: 48 bits of data specific to the implementation
The rippled-specific format (implementation ID is: 0x18 0x3B) is:
00011000-00111011-MMMMMMMM-mmmmmmmm-pppppppp-TTNNNNNN-00000000-00000000
M: 8-bit major version (0-255)
m: 8-bit minor version (0-255)
p: 8-bit patch version (0-255)
T: 11 if neither an RC nor a beta
10 if an RC
01 if a beta
N: 6-bit rc/beta number (1-63)
This commit introduces the "HardenedValidations" amendment which,
if enabled, allows validators to include additional information in
their validations that can increase the robustness of consensus.
Specifically, the commit introduces a new optional field that can
be set in validation messages can be used to attest to the hash of
the latest ledger that a validator considers to be fully validated.
Additionally, the commit leverages the previously introduced "cookie"
field to improve the robustness of the network by making it possible
for servers to automatically detect accidental misconfiguration which
results in two or more validators using the same validation key.
The new 'Domain' field allows validator operators to associate a domain
name with their manifest in a transparent and independently verifiable
fashion.
It is important to point out that while this system can cryptographically
prove that a particular validator claims to be associated with a domain
it does *NOT* prove that the validator is, actually, associated with that
domain.
Domain owners will have to cryptographically attest to operating particular
validators that claim to be associated with that domain. One option for
doing so would be by making available a file over HTTPS under the domain
being claimed, which is verified separately (e.g. by ensuring that the
certificate used to serve the file matches the domain being claimed) and
which contains the long-term master public keys of validator(s) associated
with that domain.
Credit for an early prototype of this idea goes to GitHub user @cryptobrad
who introduced a PR that would allow a validator list publisher to attest
that a particular validator was associated with a domain. The idea may be
worth revisiting as a way of verifying the domain name claimed by the
validator's operator.
