Superfluid Staking
Abstract
Superfluid Staking provides the consensus layer more security with a
sort of "Proof of Useful Stake". Each person gets an amount of Fury
representative of the value of their share of liquidity pool tokens
staked and delegated to validators, resulting in the security guarantee
of the consensus layer to also be based on GAMM LP shares. The FURY
token is minted and burned in the context of Superfluid Staking.
Throughout all of this, FURY's supply is preserved in queries to the
bank module.
The process
All of the below methods are found under the Superfluid
modules.
- The
SuperfluidDelegate
method stores your share of bonded
liquidity pool tokens, with validateLock
as a verifier for lockup
time.
GetSuperfluidFury
mints FURY tokens each day for delegation as a
representative of the value of your pool share. This amount is
minted because the staking module at the moment requires staked
tokens to be in FURY. This amount is burned each day and re-minted
to keep the representative amount of the value of your pool share
accurate. The lockup duration is guaranteed from the underlying
lockup module.
GetExpectedDelegationAmount
iterates over each (denom, delegate)
pair and checks for how much FURY we have delegated. The difference
from the current balance to what is expected is burned / minted to
match with the expected.
- A
messageServer
method executes the Superfluid delegate message.
syntheticLockup
is used to index bond holders and tracking their
addresses for reward distribution or potentially slashing purposes.
These track whether if your Superfluid stake is currently bonding or
unbonding.
- An
IntermediaryAccount
is mostly used for the actual reward
distribution or slashing events, and are responsible for
establishing the connection between each superfluid staked lock and
their delegation to the validator. These work by transferring the
superfluid FURY to their respective delegators. Rewards are linearly
scaled based on how much you have locked for a given (validator,
denom) pair. Rewards are first moved to the incentive gauges, then
distributed from the gauges. In this way, we're using the existing
gauge reward system for paying out superfluid staking rewards and
tracking the amount you have superfluidly staked using the lockup
module.
- Rewards are distributed per epoch, which is currently a day.
abci.go
checks whether or not the current block is at the
beginning of the epoch using BeginBlock
.
- Superfluid staking will continue to expand to other Furyans pools
based on governance proposals and vote turnouts.
Example
If Alice has 500 GAMM tokens bonded to the ATOM <> FURY, she will have
the equivalent value of FURY minted, delegated to her chosen staker, and
burned for her each day with Superfluid staking. On the user side, all
she has to know is who she wants to delegate her tokens to. In order to
switch delegation, she has to unbond her tokens from the pool first and
then redeposit. Bob, who has a share of the same liquidity pool before
Superfluid Staking went live, also has to re-deposit into the pool for
the above process to kickstart.
Why mint Fury? How is this method safe and accurate?
Superfluid staking requires the minting of FURY because in order to
stake on the Furyans chain, FURY tokens are required as the chosen
collateral. Synthetic Fury is minted here as a representative of the
value of each superfluid staker's liquidity pool tokens.
The pool tokens are acquired by the user from normally staking in a
liquidity pool. They get minted an amount of FURY equivalent to the
value of their GAMM pool tokens. This method is accurate because
querying the value FURY every day allows for burning and minting
according to the difference in value of FURY relative to the expected
delegation amount (as seen with
GetExpectedDelegationAmount).
It's like having a price oracle for fairly calculating the amount the
user has superfluidly staked.
On epoch (start of every day), we read from the lockup module how much
GAMM tokens we have locked which acts as an oracle for the
representative price of the GAMM token shares. The superfluid module has
"hooks" messages to refresh delegation amounts
(RefreshIntermediaryDelegationAmounts
) and to increase delegation on
lockup (IncreaseSuperfluidDelegation
). Then, we see whether or not the
superfluid FURY currently delegated is worth more or less than this
expected delegation amount amount. If the FURY is worth more, we do
instant undelegations and immediately burn the FURY. If less, we mint
FURY and update the amount delegated. A simplified diagram of this whole
process is found below:
This minting is safe because we strict constrain the permissions of Bank
(the module that burns and mints FURY) to do what it's designed to do.
The authority is mediated through mintFuryTokensAndDelegate
and
forceUndelegateAndBurnFuryTokens
keeper methods called by the
SuperfluidDelegate
and SuperfluidUndelegate
message handlers for the
tokens. The hooks above that increase delegation and refresh delegation
amounts also call this keeper method.
The delegation is then verified to not already be associated with an
intermediary account (to prevent double-staking), and is always
delegated or withdrawn taking into account various multipliers for
synthetic FURY value (its worth with respect to the liquidity pool, and
a risk modifier) to prevent mint inaccuracies. Before minting, we also
check that the message sender is the owner of the locked funds; that the
lock is not unlocking; is locked for at least the unbonding period, and
is bonded to a single asset. We also check to see if the lock isn't
already in superfluid and that the same lock isn't currently being
unbonded.
On the end of each epoch, we iterate through all intermediary accounts
to withdraw delegation rewards they may have received and put it all
into the perpetual gauges corresponding to each account for reward
delegation.
Bonding, unbonding, slashing
Here, we describe how token bonding and unbonding works, and what
happens to your superfluid tokens in the case of a slashing event.
Bonding
When bonding, your input tokens are locked up and you are given GAMM
pool tokens in exchange. These GAMM pool tokens represent a share of the
total liquidity pool, and allows you to get transaction fees or
participate in external incentive gauge token distributions. When
bonding, on top of the regular bonding transaction there will also be a
selection of validators. As stated above, FURY is also minted and burned
each day and superfluidly staked to whoever you have chosen to be your
validator. You gain additional APR as a reward for bolstering the
Furyans chain's consensus integrity by delegating.
Unbonding
When unbonding, superfluid tokens get un-delegated. After making sure
that the unbond message sender is the owner of their corresponding
locked funds, the existing synthetic lockup is deleted and replaced with
a new synthetic lockup for unbonding purposes. The undelegated FURY is
then instantly withdrawn from the intermediate account and validator
using the InstantUndelegate function. The FURY that was originally used
for representing your LP shares are burnt. Moves the tracker for
unbonding, allows the underlying lock to start unlocking if desired
Concepts
SyntheticLockups
SyntheticLockups are synthetica of PeriodLocks, but different in the
sense that they store suffix, which is a combination of
bonding/unbonding status + validator address. This is mainly used to
track whether an individual lock that has been superfluid staked has an
bonding status or a unbonding status from the staking delegations.
Intermediary Accounts establishes the connections between the superfluid
staked locks and delegations to the validator. Intermediary accounts
exists for every denom + validator combination, so that it would group
locks with the same denom + validator selection. Superfluid staking a
lock would mint equivalent amount of FURY of the lock and send it to the
intermediary account and the intermediarry accounts would be delegating
to the specified validator.
Intermediary Accounts Connection serves the role of tracking the locks
that an Intermediary Account is dedicated to.
State
Superfluid Asset
A superfluid asset is a alternative asset (non-FURY) that is allowed by
governance to be used for staking.
It can only be updated by governance proposals. We validate at proposal
creation time that the denom + pool exists. (Are we going to ignore edge
cases around a reference pool getting deleted it)
Lots of questions to be answered here
Dedicated Gauges
Each intermediary account has has dedicated gauge where it sends the
delegation rewards to. Gauges are distributing the rewards to end users
at the end of the epoch.
Synthetic Lockups created
At the moment, one lock can only be fully bonded to one validator.
Fury Equivalent Multipliers
The Fury Equivalent Multiplier for an asset is the multiplier it has for
its value relative to FURY.
Different types of assets can have different functions for calculating
their multiplier. We currently support two asset types.
- Native Token
The multiplier for FURY is alway 1.
- Gamm LP Shares
Currently we use the spot price for an asset based on a designated
fury-basepair pool of an asset. The multiplier is set once per epoch, at
the beginning of the epoch. In the future, we will switch this out to
use a TWAP instead.
State changes
The state of superfluid module state modifiers are classified into below
categories.
Messages
Superfluid Delegate
Owners of superfluid asset locks can submit MsgSuperfluidDelegate
transactions to delegate the Fury in their locks to a selected
validator.
type MsgSuperfluidDelegate struct {
Sender string
LockId uint64
ValAddr string
}
State Modifications:
- Safety Checks that are being done before running superfluid logic:
- Check that
Sender
is the owner of lock
- Check that
lock
corresponds to a single locked asset
- Check that
lock
is not unlocking
- Check that
lock
is locked for at least the unbonding period
- Check that this
LockID
is not already superfluided
- Check that the same lock isn't being unbonded
- Get the
IntermediaryAccount
for this lock's Denom
and ValAddr
pair.
- Create it + a new gauge for the synthetic denom, if it does not
yet exist.
- Create a SyntheticLockup.
- Calculate
Fury
to delegate on behalf of this lock
, as
Fury Equivalent Multiplier
* # LP Shares
*
Risk Adjustment Factor
- If this amount is less than 0.000001
Fury
(1 ufury
) reject
the transaction, as it would be delegating 0 ufury
- Mint
Fury
to match this amount and send to IntermediaryAccount
- Create a delegation from
IntermediaryAccount
to Validator
- Create a new perpetual
Gauge
for distributing staking payouts to
locks of a synethic asset based on this Validator
/ Denom
pair.
- Create a connection between this
lockID
and this
IntermediaryAccount
Superfluid Undelegate
type MsgSuperfluidUndelegate struct {
Sender string
LockId uint64
}
State Modifications:
- Lookup
lock
by LockID
- Check that
Sender
is the owner of lock
- Get the
IntermediaryAccount
for this lockID
- Delete the
SyntheticLockup
associated to this lockID
+ ValAddr
pair
- Create a new
SyntheticLockup
which is unbonding
- Calculate the amount of
Fury
delegated on behalf of this lock
as
Fury Equivalent Multipler
* # LP Shares
*
Risk Adjustment Factor
- If this amount is less than 0.000001
Fury
, there is no
delegated Fury
to undelegate and burn
- Use
InstantUndelegate
to instantly remove delegation from
IntermediaryAccount
to Validator
- Immediately burn undelegated
Fury
- Delete the connection between
lockID
and IntermediaryAccount
Lock and Superfluid Delegate
type MsgLockAndSuperfluidDelegate struct {
Sender string
Coins sdk.Coins
ValAddr string
}
This is effectively a multimsg tx of lockup's MsgLockTokens
and
superfluid's MsgSuperfluidDelegate
, but it is implemented as a single
msg, because currently we don't have a way of passing the lockid
outputted by MsgLockTokens
as an input into the
MsgSuperfluidDelegate
prior to execution.
State Modifications:
- Ensures that Coins has a length of only 1 (we use sdk.Coins instead
of sdk.Coin in order to allow more flexibility in the future)
- Creates a lockup with Coins of a lock duration equivalent to the
unstaking period from the staking module
- Uses the lockup module's MsgServer
- Gets the lock id of the created lock, and uses it generate and
execute a MsgSuperfluidDelegate message
- Uses the SuperfluidDelegate function on this msg server
Superfluid Unbond Lock
type MsgSuperfluidUnbondLock struct {
Sender string
LockId uint64
}
This message does all the functionality of MsgSuperfluidUndelegate
but
also starts unbonding the underlying lock as well, allowing both the
unstaking and unlocking to complete at the same time. Without using this
function, a user will not be able to start unbonding their underlying
lock until after the the unstaking has finished.
State Modifications:
- This runs the functionality of
MsgSuperfluidUndelegate
- It then triggers a force unbond of the underlying lock id
Epochs
Overall Epoch sequence
- Epoch N ends, during AfterEpochEnd:
- Distribute gauge rewards for all non-superfluid gauges
- Mint new tokens
- Issue new Fury, and send to various modules (distribution,
incentives, etc.)
- 25% currently goes to
x/distribution
which funds Staking
and Superfluid
rewards
- Rewards for
Superfluid
are based on the just updated
delegation amounts, and queued for payout in the next epoch
- BeginBlock for Distribution
- Distribute staking rewards to all of the 'lazy accounting'
accumulators. (F1)
- Epoch N ends, during BeginBlock for superfluid After
AfterEpochEnd:
- Claim staking rewards for every
Intermediary Account
, put them
into gauges.
- Distribute Superfluid staking rewards from gauges to bonded
Synthetic Lock owners
- Update
Fury Equivalent Multiplier
value for each LP token
- (Currently spot price at epoch)
- Refresh delegation amounts for all
Intermediary Accounts
- Calculate the expected delegation for this account as
Fury Equivalent Multipler
# LP Shares
Risk adjustment
- If this is less than 0.000001
Fury
it will be rounded
to 0
- Lookup current delegation amount for
Intermediary Account
- If there is no delegation, treat the current delegation
as 0
- If expected amount > current delegation:
- Mint new
Fury
and Delegate
to Validator
- If expected amount < current delegation:
- Use
InstantUndelegate
and burn the received Fury
Staking power updates
We need to be concerned with how/when validators enter and leave the
active set.
We expect the guarantee that there is an Intermediary account for every
(active validator, superfluid denom) pair, and every (unbonding
validator, superfluid denom) pair. (TODO: Where/why)
We also want to avoid resource exhaustion attacks. We relegate concerns
around upper-bounding the number of active + unbonding validators to the
staking module. This module is liable to potentially cause a 100-1000x
amplification factor on this workload.
How we handle it now
- Intermediary accounts are not created on SetSuperfluidAsset
- They are created at-time-of-need on MsgSuperfluidDelegate
- Concerns: What happens if you delegate to an unbonding or jailed
validator. Note: Isn't it same as normal delegation for unbonding
validator?
Other Module Hooks
-----;
In this section we describe the "hooks" that superfluid
module
receives from other modules.
AfterEpochEnd
On AfterEpochEnd, we iterate through all existing intermediary accounts
and withdraw delegation rewards they have received. Then we send the
collective rewards to the perpetual gauge corresponding to the
intermediary account. Then we update FURY backing per share for the
specific pool. After the update, iteration through all intermediate
accounts happen, undelegating and bonding existing delegations for all
superfluid staking and use the updated spot price at epoch time to mint
and delegate.
AfterAddTokensToLock
When a token is locked, we first check if the corresponding lock is
currently in the state of superfluid delegation. If it is, we run the
logic to add delegation via intermediary account.
BeforeValidatorSlashed
Slashes the synthetic lockups and native lockups that is connected to
the to be slashed validator.
Proposal Hooks
-----;
In this section we describe the proposals that is associated to
superfluid module.
SetSuperfluidAssetsProposal
Enable multiple superfluid assets to be used for superfluid staking.
RemoveSuperfluidAssetsProposal
Disable multiple assets from being used for superfluid staking.
Events
There are 7 types of events that exist in Superfluid module:
types.TypeEvtSetSuperfluidAsset
- "set_superfluid_asset"
types.TypeEvtRemoveSuperfluidAsset
- "remove_superfluid_asset"
types.TypeEvtSuperfluidDelegate
- "superfluid_delegate"
types.TypeEvtSuperfluidIncreaseDelegation
- "superfluid_increase_delegation"
types.TypeEvtSuperfluidUndelegate
- "superfluid_undelegate"
types.TypeEvtSuperfluidUnbondLock
- "superfluid_unbond_lock"
types.TypeEvtUnpoolId
- "unpool_pool_id"
types.TypeEvtSetSuperfluidAsset
This event is emitted in the proposal which set new superfluid asset
It consists of the following attributes:
types.AttributeDenom
- The value is the asset denom.
types.AttributeSuperfluidAssetType
- The value is the type of asset.
types.TypeEvtRemoveSuperfluidAsset
This event is emitted in the proposal which removes the superfluid asset
It consists of the following attributes:
types.AttributeDenom
- The value is the asset denom.
types.TypeEvtSuperfluidDelegate
This event is emitted in the message server after successfully creating a delegation for the given lock ID and the validator to delegate to.
It consists of the following attributes:
types.AttributeLockId
- The value is the given lock ID.
types.AttributeValidator
- The value is the validator address to delegate to.
types.TypeEvtSuperfluidIncreaseDelegation
This event is emitted in the hook after adding more token to the existing lock
It consists of the following attributes:
types.AttributeLockId
- The value is the given lock ID.
types.AttributeAmount
- The value is the token amount added to the lock.
types.TypeEvtSuperfluidUndelegate
This event is emitted in the message server after undelegating the currently superfluid delegated position given by lock ID.
It consists of the following attributes:
types.AttributeLockId
- The value is the given lock ID.
types.TypeEvtSuperfluidUnbondLock
This event is emitted in the message server after starting unbonding for the currently superfluid undelegating lock.
It consists of the following attributes:
types.AttributeLockId
- The value is the given lock ID.
types.TypeEvtUnpoolId
This event is emitted in the message server UnPoolWhitelistedPool
It consists of the following attributes:
types.AttributeKeySender
- The value is the msg sender address.
types.AttributeLockId
- The value is the pool lpShareDenom.
types.AttributeNewLockIds
- The value is the exited lock ids in byte[].
Messages
MsgSuperfluidDelegate
Type |
Attribute Key |
Attribute Value |
superfluid_delegate |
lock_id |
{lock_id} |
superfluid_delegate |
validator |
{validator} |
MsgSuperfluidUndelegate
Type |
Attribute Key |
Attribute Value |
superfluid_undelegate |
lock_id |
{lock_id} |
MsgSuperfluidUnbondLock
Type |
Attribute Key |
Attribute Value |
superfluid_unbond_lock |
lock_id |
{lock_id} |
MsgLockAndSuperfluidDelegate
Type |
Attribute Key |
Attribute Value |
lock_tokens |
period_lock_id |
{periodLockID} |
lock_tokens |
owner |
{owner} |
lock_tokens |
amount |
{amount} |
lock_tokens |
duration |
{duration} |
lock_tokens |
unlock_time |
{unlockTime} |
message |
action |
lock_tokens |
message |
sender |
{owner} |
transfer |
recipient |
{moduleAccount} |
transfer |
sender |
{owner} |
transfer |
amount |
{amount} |
superfluid_delegate |
lock_id |
{lock_id} |
superfluid_delegate |
validator |
{validator} |
Proposals
SetSuperfluidAssetsProposal
Type |
Attribute Key |
Attribute Value |
set_superfluid_asset |
denom |
{denom} |
set_superfluid_asset |
superfluid_asset_type |
{asset_type} |
RemoveSuperfluidAssetsProposal
Type |
Attribute Key |
Attribute Value |
remove_superfluid_asset |
denom |
{denom} |
Queries
Params
message ParamsRequest {};
message ParamsResponse {
// params defines the parameters of the module.
Params params = 1 [ (gogoproto.nullable) = false ];
}
message Params {
sdk.Dec minimum_risk_factor = 1; // serialized as string
}
The params query returns the params for the superfluid module. This
currently contains:
MinimumRiskFactor
which is an sdk.Dec that represents the discount
to apply to all superfluid staked modules when calcultating their
staking power. For example, if a specific denom has an FURY
equivalent value of 100 FURY, but the the MinimumRiskFactor
param
is 0.05, then the denom will only get 95 FURY worth of staking power
when staked.
AssetType
message AssetTypeRequest {
string denom = 1;
};
message AssetTypeResponse {
SuperfluidAssetType asset_type = 1;
};
enum SuperfluidAssetType {
SuperfluidAssetTypeNative = 0;
SuperfluidAssetTypeLPShare = 1;
}
The AssetType query returns what type of superfluid asset a denom is.
AssetTypes are meant for when we support more types of assets for
superfluid staking than just LP shares. Each AssetType has a different
algorithm used to get its "Fury equivalent value".
We represent different types of superfluid assets as different enums.
Currently, only enum 1
is actually used. Enum value 0
is reserved
for the Native staking token for if we deprecate the legacy staking
workflow to have native staking also go through the superfluid module.
In the future, more enums will be added.
If this query errors, that means that a denom is not allowed to be used
for superfluid staking.
AllAssets
message AllAssetsRequest {};
message AllAssetsResponse {
repeated SuperfluidAsset assets = 1 [ (gogoproto.nullable) = false ];
};
message SuperfluidAsset {
string denom = 1;
SuperfluidAssetType asset_type = 2;
}
This parameterless query returns a list of all the superfluid staking
compatible assets. The return value includes a list of SuperfluidAssets,
which are pairs of denom
with SuperfluidAssetType
which was
described in the previous section.
This query does not currently support pagination, but may in the future.
AssetMultiplier
message AssetMultiplierRequest {
string denom = 1;
};
message AssetMultiplierResponse {
FuryEquivalentMultiplierRecord fury_equivalent_multiplier = 1;
};
message FuryEquivalentMultiplierRecord {
int64 epoch_number = 1;
string denom = 2;
string multiplier = 3;
}
This query allows you to find the multiplier factor on a specific denom.
The Fury-Equivalent-Multiplier Record for epoch N refers to the fury
worth we treat a denom as having, for all of epoch N. For now, this is
the spot price at the last epoch boundary, and this is reset every
epoch. We currently don't store historical multipliers, so the epoch
parameter is kind of meaningless for now.
To calculate the staking power of the denom, one needs to multiply the
amount of the denom with FuryEquivalentMultipler
from this query with
the MinimumRiskFactor
from the Params query endpoint.
staking_power = amount * FuryEquivalentMultipler * MinimumRiskFactor
message ConnectedIntermediaryAccountRequest {
uint64 lock_id = 1;
}
message ConnectedIntermediaryAccountResponse {
SuperfluidIntermediaryAccountInfo account = 1;
}
message SuperfluidIntermediaryAccount {
string denom = 1;
string val_addr = 2;
uint64 gauge_id = 3; // perpetual gauge for rewards distribution
}
Every superfluid denom and validator pair has an associated
"intermediary account", which does the actual delegation. This query
helps find the superfluid intermediary account for any superfluid
position.
That lock_id
parameter passed in is the underlying lock id for the
superfluid, NOT the synthetic lock id.
This query can be used to find the validator a superfluid lock is
delegated to. The gauge_id
also refers to the perpetual gauge that is
used to pay out the superfluid positions associated with this
intermediary account.
message AllIntermediaryAccountsRequest {
cosmos.base.query.v1beta1.PageRequest pagination = 1;
};
message AllIntermediaryAccountsResponse {
repeated SuperfluidIntermediaryAccountInfo accounts = 1;
cosmos.base.query.v1beta1.PageResponse pagination = 2;
};
This query returns a list of all superfluid intermediary accounts. It
supports pagination.
SuperfluidDelegationAmount
message SuperfluidDelegationAmountRequest {
string delegator_address = 1;
string validator_address = 2;
string denom = 3;
}
message SuperfluidDelegationAmountResponse {
repeated cosmos.base.v1beta1.Coin amount = 1 [];
}
This query returns the amount of underlying denom (i.e. lp share) for a
triplet of delegator, validator, and denom.
SuperfluidDelegationsByDelegator
message SuperfluidDelegationsByDelegatorRequest {
string delegator_address = 1;
}
message SuperfluidDelegationsByDelegatorResponse {
repeated SuperfluidDelegationRecord superfluid_delegation_records = 1;
repeated cosmos.base.v1beta1.Coin total_delegated_coins = 2;
}
message SuperfluidDelegationRecord {
string delegator_address = 1;
string validator_address = 2;
cosmos.base.v1beta1.Coin delegation_amount = 3;
}
This query returns a list of all the superfluid delegations of a
specific delegator. The return value includes, the validator delgated to
and the delegated coins (both denom and amount).
The return value of the query also includes the total_delegated_coins
which is the sum of all the delegations of that validator.
This query does require iteration that is linear with the number of
delegations a delegator has made, but for now until we support many
superfluid denoms, should be relatively bounded. Once that increases, we
will need to support pagination.
SuperfluidDelegationsByValidatorDenom
message SuperfluidDelegationsByValidatorDenomRequest {
string validator_address = 1;
string denom = 2;
}
message SuperfluidDelegationsByValidatorDenomResponse {
repeated SuperfluidDelegationRecord superfluid_delegation_records = 1;
}
This query returns a list of all superfluid delegations that are with a
validator / superfluid denom pair. This query requires a lot of
iteration and should be used sparingly. We will need to add pagination
to make this usable.
EstimateSuperfluidDelegatedAmountByValidatorDenom
message EstimateSuperfluidDelegatedAmountByValidatorDenomRequest {
string validator_address = 1;
string denom = 2;
}
message EstimateSuperfluidDelegatedAmountByValidatorDenomResponse {
repeated cosmos.base.v1beta1.Coin total_delegated_coins = 1;
}
This query returns the total amount of delegated coins for a validator /
superfluid denom pair. This query does NOT involve iteration, so should
be used instead of the above SuperfluidDelegationsByValidatorDenom
whenever possible. It is called an "Estimate" because it can have some
slight rounding errors, due to conversions between sdk.Dec and
sdk.Int", but for the most part it should be very close to the sum of
the results of the previous query.
Parameters
The superfluid module contains the following parameters:
Key |
Type |
Example |
minimum_risk_factor |
decimal |
0.01 |
Slashing
Slashing works by gathering all accounts who were superfluidly staking
and delegated to the violating validator and slashing their underlying
lock collateral. The amount of tokens to slash are first calculated then
removed from the underlying and synthetic lock. Therefore, it is
important to select a reputable or reliable validator as to minimize
slashing risks on your tokens. At the moment we are slashing at latest
price rather than block height price. All slashed tokens go to the
community pool.
We first get a hook from the staking module, marking that a validator is
about to be slashed at a slashFactor of f
, for an infraction at height
h
.
The staking module handles slashing every delegation to that validator,
which will handle slashing the delegation from every intermediary
account. However, it is up to the superfluid module to then:
- Slash every constituent superfluid staking position for this
validator.
- Slash every unbonding superfluid staking position to this validator.
We do this by:
- Collect all intermediate accounts to this validator
- For each IA, iterate over every lock to the underlying native denom.
- If the lock has a synthetic lockup, it gets slashed.
- The slash works by calculating the amount of tokens to slash.
- It removes these from the underlying lock and the synthetic lock.
- These coins are moved to the community pool.
Nuances
- Slashed tokens go to the community pool, rather than being burned as
in staking.
- We slash every unbonding, rather than just unbondings that started
after the infraction height.
- We can "overslash" relative to the staking module. (For a slash
factor of 5%, the staking module can often burn <5% of active
delegation, but superfluid will always slash 5%)
We slash every unbonding, purely because lockup module tracks things by
unbonding start time, whereas staking/slashing tracks things by height
we begin unbonding at. Thus we get a problem that we cannot convert
between these cleanly. Really there should be a storage of all
historical block height <> block times for everything in the unbonding
period, but this is not considered a near-term problem.
Correcting overslashing
The overslashing possibility stems from a problem in the SDKs slashing
module, that really is a bug there, and superfluid is doing the correct
thing. https://github.com/cosmos/cosmos-sdk/issues/1440
Basically, slashes to unbondings and redelegations can lower the amount
that gets slashed from live delegations in the staking module today.
It turns out this edge case, where superfluid's intermediate account can
have more delegation than expected from its underlying collateral, is
already safely handled by the Superfluid refreshing logic.
The refreshing logic checks the total amount of tokens in locks to this
denom (Reading from the lockup accumulation store), calculates how many
fury thats worth at the epochs new fury worth for that asset, and then
uses that. Thus this safely handles this edge case, as it uses the new
'live' lockup amount.
Minting
Superfluid module has the ability to arbitrarily mint and burn Fury
through the bank
module. This is potentially dangerous so we strictly
constrain it's ability to do so. This authority is mediated through the
mintFuryTokensAndDelegate
and forceUndelegateAndBurnFuryTokens
keeper methods, which are in turn called by message handlers
(SuperfluidDelegate
and SuperfluidUndelegate
) as well as by hooks on
Epoch (RefreshIntermediaryDelegationAmounts
) and Lockup
(IncreaseSuperfluidDelegation
)
Invariant
Each of these mechanisms maintains a local invariant between the amount
of Fury minted and delegated by the IntermediaryAccount
, and the
quantity of the underlying asset held by locks associated to the
account, modified by FuryEquivalentMultiplier
and RiskAdjustment
for
the underlying asset. Namely that total minted/delegated =
GetTotalSyntheticAssetsLocked
* GetFuryEquivalentMultiplier
*
GetRiskAdjustment
This can be equivalently expressed as GetExpectedDelegationAmount
being equal to the actual delegation amount.
Message Handlers
SuperfluidDelegate
In a SuperfluidDelegate
transaction, we first verify that this lock is
not already associated to an IntermediaryAccount
, and then use
mintFuryTokenAndDelegate
to properly balance the resulting change in
GetExpectedDelegationAmount
from the increase in
GetTotalSyntheticAssetsLocked
. i.e. we mint and delegate:
GetFuryEquivalentMultiplier
* GetRiskAdjustment
*
lock.Coins.Amount
new Fury tokens.
SuperfluidUndelegate
When a user submits a transaction to unlock their asset the invariant is
maintained by using forceUndelegateAndBurnFuryTokens
to remove an
amount of Fury equal to lockedCoin.Amount
*
GetFuryEquivalentMultiplier
* GetRiskAdjustment
.
Superfluid Hooks
In the RefreshIntermediaryDelegationAmounts
method, calls are made to
mintFuryTokensAndDelegate
or forceUndelegateAndBurnFuryTokens
to
adjust the real delegation up or down to match
GetExpectedDelegationAmount
.
IncreaseSuperfluidDelegation (AfterAddTokensToLock Hook)
This is called as a result of a user adding more assets to a lock that
has already been associated to an IntermediaryAccount
. The invariant
is maintained by using mintFuryTokenAndDelegate
to match the amount of
new asset locked * GetFuryEquivalentMultiplier
* GetRiskAdjustment
for the underlying asset.
SlashLockupsForValidatorSlash (BeforeValidatorSlashed Hook)
During slashing the invariant is likely to be temporraily broken if the
referenced validator has any unbonding delegations. These unbonding
delegations are slashed first, which means that the amount delegated by
the IntermediaryAccount
will be slashed by less than the
SyntheticLock
s held by the account.
See Also
GetTotalSyntheticAssetsLocked
TODO - expand on this Uses lockup
accumulator to find total amount of
synthetic locks for a given IntermediaryAccount
(Superfluid Asset +
Validator pair)