A financially accountable
watching network
Patrick McCorry
PisaResearch
paddypisa
WHY IS OFF-CHAIN EXCITING?
10k+ tx
authorised off-chain
1 tx to join off-chain protocol
1 tx to leave off-chain protocol
Bypass all blockchain latency and fees
While still retaining non-custodial security guarantees.
Only scaling solution that will exceed 10k tps
99% of transactions are LOCAL and
never reach the global network.
But what does an “off-chain network” look like?
P2P Routing Network
Non-Custodial Hubs
P2P Routing Network
Non-Custodial Hubs
P2P Routing Network
Watching Network
Non-Custodial Hubs
P2P Routing Network
Watching Network
Settlement System and
Root of Trust of all Layer 2
Settlement System and
Root of Trust of all Layer 2
Non-Custodial Hubs
P2P Routing Network
Watching Network
Open-source, global, permissionless and non-custodial financial system.
It is coming…
Settlement System and
Root of Trust of all Layer 2
Plasma Group
Plenty of talks about channels + plasma.
We’ll “briefly” talk about how replace-by-revocation works before deep-diving into the watching network
Watching Network
What does a lightning channel look like? (replace-by-revocation)
State 1A
State 1B
Alice and Bob always have a transaction (“state”) that only they can broadcast to trigger a dispute.
What does a lightning channel look like? (replace-by-revocation)
Authorising a payment is a two-step process
State 1A
State 1B
What does a lightning channel look like? (replace-by-revocation)
State 1A
State 1B
State 2B
σA
State 2A
σB
What does a lightning channel look like? (replace-by-revocation)
State 1A
State 1B
Either State 1 or State 2 can be broadcast…
Second step revokes old balance and confirms the new one.
State 2A
State 2B
What does a lightning channel look like? (replace-by-revocation)
State 1A
State 1B
State 1A
2. Both parties will “revoke” the old state �(i.e. share pre-image of hash)
State 1B
State 2A
State 2B
What does a lightning channel look like? (replace-by-revocation)
State 1A
State 1B
Complete!
Both parties can always broadcast the latest state.
State 2A
State 2B
What does a lightning channel look like? (replace-by-revocation)
State 1
… and a growing list of revoked states… as we will see,
this will be problematic...
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
What if Alice stops co-operating (she is offline)?
Bob can try to close the channel based on a
“revoked” state that repays him back his coins.
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
Block 11
...
...
Block 100
On-chain dispute process...
If there is no response by Alice by block 100,
then Bob will get all his coins back based on the revoked state.
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
Block 11
...
...
Block 100
Blocks are getting minted...
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
Block 11
...
...
Block 100
Yet no response from Alice…
But … if Alice were online… what exactly would she respond with?
What does a lightning channel look like? (replace-by-revocation)
State 1
JUSTICE TRANSACTION
Alice can steal all coins in the channel (i.e. spend the outputs) by signing a justice transaction
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
Block 11
...
...
Block 100
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
Block 11
...
...
Block 100
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
Block 11
...
...
Block 100
What does a lightning channel look like? (replace-by-revocation)
State 1
State N(B)
State ...
State N-1
State 1
State ...
State N-1
State N(A)
...
Block 10
Block 11
...
...
Block 100
Alice wins!
Her JUSTICE TRANSACTION was accepted into the blockchain before the dispute process expired!
She punished Bob for trying to cheat by taking all coins in the channel.
FAQ: Can Alice just keep a pre-signed justice tx around?
FAQ: Can Alice just keep a pre-signed justice tx around?
State 1
State 2
State ...
State N
Why?
Bob has a LIST of REVOKED transactions that only HE can broadcast….
She must be ready to prove any of them are invalid…
Remember, UTXO!
FAQ: Under the hood - what does it look like (roughly speaking)
1 BTC, A & B
Funding Transaction
FAQ: Under the hood - what does it look like (roughly speaking)
1 BTC, A & B
Funding Transaction
0.5 BTC,
B, t
A, H(S)
σA
Bob’s Tx (State N)
0.5 BTC,
A
Alice’s Tx (State N)
Symmetric to Bob’s tx
We omit it for space
Every state compromises of TWO transactions
1 transaction only Alice can broadcast
1 transaction only Bob can broadcast
FAQ: Under the hood - what does it look like (roughly speaking)
1 BTC, A & B
Funding Transaction
0.5 BTC,
B, t
A, H(S)
Bob’s Tx (State N)
0.5 BTC,
A
Alice’s Tx (State N)
Bob’s balance
He can claim it after time t OR
Alice can claim it immediately if S is revealed
Alice’s balance
She can redeem it immediately
σA
FAQ: Under the hood - what does it look like (roughly speaking)
1 BTC, A & B
Funding Transaction
0.5 BTC,
B, t
A, H(S)
Bob’s Tx (State N)
0.5 BTC,
A
Alice’s Tx (State N)
σA,σB
Bob broadcasts it
He can just sign and broadcast it at any time… to trigger the dispute period (up to time t)
FAQ: Under the hood - what does it look like (roughly speaking)
1 BTC, A & B
Funding Transaction
0.5 BTC,
B, t
A, H(S)
Bob’s Tx (State N)
0.5 BTC,
A
Alice’s Tx (State N)
1 BTC, A
Alice’s JUSTICE TX
σA, S
σA
σA,σB
Now we know how Lightning Channels (replace-by-revocation) roughly works…
Let’s better understand this watching network
Watching Network
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
Monitor (Tadge) @ Scaling Bitcoin ‘16
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Watch Tower
But what does she send to the watch tower?
Monitor (Tadge) @ Scaling Bitcoin ‘16
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Watch Tower
0.5 BTC,
B, t
A, H(S)
Bob’s Tx (State N)
0.5 BTC,
A
1 BTC, A
Alice’s JUSTICE TX
σA, S
σA
σA,σB
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
TXID [32 bytes]
TxLocator = [16:0]
Encryption Key = [16:32]
Bob’s TX (State N)
Tx Locator
Let’s watching service find transaction when dispute is triggered�
Encryption Key
Used to encryption Justice Transaction, only discoverable when a dispute is triggered.
4410c8d14ff9f87ceeed1d65cb58e7c7b2422b2d7529afc675208ce2ce09ed7d
TxLocator
Encryption Key
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
TXID [32 bytes]
TxLocator = [16:0]
Encryption Key = [16:32]
Bob’s TX (State N)
Encrypted Justice Transaction
Alice encrypts the pre-signed justice transaction.
It can ONLY be decrypted by watchtower if there is a dispute
(or if bob leaks the key)
1 BTC, A
Encrypted Justice TX
σA, S
σA
Monitor (Tadge) @ Scaling Bitcoin ‘16
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Watch Tower
Send to the Watching Service
TxLocator & Encrypted Justice Transaction
TxLocator & Encrypted Justice Transaction
Monitor (Tadge) @ Scaling Bitcoin ‘16
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Watch Tower
...
Block 10
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
Watching Service - 5 Steps�
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
Watching Service - 5 Steps�
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
Watching Service - 5 Steps�
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
Block 12
Let’s look at the good, bad and the ugly
Monitor - THE GOOD
Leaning
Watch Tower
Channel-Privacy
We don’t know anything about channel until dispute
(Can also send us junk)
Simple Protocol
Just store encrypted blob and watch blockchain to retrieve decryption key
Responder, not trigger
We CANNOT trigger any disputes! Only respond if the counterparty tries to cheat.
Monitor - THE GOOD, BAD
Leaning
Watch Tower
Channel-Privacy
We don’t know anything about channel until dispute
(Can also send us junk)
Simple Protocol
Just store encrypted blob and watch blockchain to retrieve decryption key
O(N) Storage
Watching service must store a justice transaction for EVERY new state update.
Congestion BIG problem
Watching service only has a pre-signed transaction and very very awkward to bump fees
Responder, not trigger
We CANNOT trigger any disputes! Only respond if the counterparty tries to cheat.
Monitor - THE GOOD, BAD, AND THE UGLY
Leaning
Watch Tower
Channel-Privacy
We don’t know anything about channel until dispute
(Can also send us junk)
Simple Protocol
Just store encrypted blob and watch blockchain to retrieve decryption key
O(N) Storage
Watching service must store a justice transaction for EVERY new state update.
Congestion BIG problem
Watching service only has a pre-signed transaction and very very awkward to bump fees
Responder, not trigger
We CANNOT trigger any disputes! Only respond if the counterparty tries to cheat.
HOPES FOR AVAILABILITY
Hire hundreds of watchers and only 1 is rewarded.
What if they don’t respond? Tough luck
View of how a “watching network” might work so far
Leaning
Watch Tower
Leaning
Watch Tower
Leaning
Watch Tower
Leaning
Watch Tower
Leaning
Watch Tower
Leaning
Watch Tower
Hire multiple watch towers
And hope one responds!
Goal for “Monitor” was CHANNEL Privacy.
Reward Policy?
Only the one watch tower who gets their respective justice tx in the blockchain will get rewarded.
WatchTower @ BPASE’18
Leaning
Watch Tower
σA, σB, i*
Signatures
State version
*The actual construction is slightly different, it commits to the “version, randomness” which is revealed, but this is easier to explain.
WatchTower @ BPASE’18
Leaning
Watch Tower
*The actual construction is slightly different, it commits to the “version, randomness” which is revealed, but this is way easier to explain.
TxLocator & σA, σB, i, $$
TxLocator:σA, σB, i
Realtime payments via Lightning
WatchTower @ BPASE’18
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator:σA, σB, i
Watching Service - 5 Steps�
WatchTower @ BPASE’18
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator:σA, σB, i
Watching Service - 5 Steps�
σA, σB, i
WatchTower @ BPASE’18
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator:σA, σB, i
Watching Service - 5 Steps�
σA, σB, i
WatchTower @ BPASE’18
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator:σA, σB, i
Watching Service - 5 Steps�
σA, σB, i
Block 12
WatchTower @ BPASE’18
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator:σA, σB, i
Watching Service - 5 Steps�
σA, σB, i
Block 12
Let’s look at the good, bad and the ugly
Watch Tower - THE GOOD
Leaning
Watch Tower
Verifiable Job
No longer store junk. We know it is a useful job.
O(1) Storage
Only store the job with the largest version.
Separates TX + State �
We are broadcasting the “latest state” and not necessarily a bitcoin transaction. Cleaner solution.
Watch Tower - THE GOOD, BAD
Leaning
Watch Tower
Verifiable Job
No longer store junk. We know it is a useful job.
O(1) Storage
Only store the job with the largest version.
No financial deterrent
We need to rely on the reputation of a watching service (or hire multiple) since no skin-in-the-game
Separates TX + State �
We are broadcasting the “latest state” and not necessarily a bitcoin transaction. Cleaner solution.
Accountability? No
No evidence a watch tower was hired and if they don’t do their job, no way to prove it.
Watch Tower - THE GOOD, BAD, AND THE UGLY
Leaning
Watch Tower
Verifiable Job
No longer store junk. We know it is a useful job.
O(1) Storage
Only store the job with the largest version.
Accountability? No
No evidence a watch tower was hired and if they don’t do their job, no way to prove it.
No financial deterrent
We need to rely on the reputation of a watching service (or hire multiple) since no skin-in-the-game
Separates TX + State �
We are broadcasting the “latest state” and not necessarily a bitcoin transaction. Cleaner solution.
Consensus Upgrade
We need a new OP_CODE for eltoo to work, so we don’t get the benefits of watch tower.
PISA @ Scaling Bitcoin ‘19
Leaning
Watch Tower
Monitor-style Jobs
TxLocator + Encrypted TX
Eltoo-style Jobs
TxLocator & Authorised State Version
We don’t care too much about the underlying payment channel construction.
It can be replace-by-revocation (today) �or replace-by-version (eltoo).
Outpost-style Jobs
TxLocator + Decryption Key
(Find out later)
PISA @ Scaling Bitcoin ‘19
Leaning
Watch Tower
On-chain evidence
If PISA doesn’t respond, clear on-chain evidence.
Signed Receipt
An acknowledgement that PISA accepted a job
PISA Contract
with security deposit
Requires a new OPCODE to support SPV Proof, parsing receipt & covenants
PISA (Monitor) @ Scaling Bitcoin ‘19
Leaning
Watch Tower
TxLocator1 & ENCJustice
PISA (Monitor) @ Scaling Bitcoin ‘19
Leaning
Watch Tower
TxLocator1 & ENCJustice
Signed Receipt
PISA (Monitor) @ Scaling Bitcoin ‘19
Leaning
Watch Tower
In-depth Signed Receipt
Encrypted Justice: ENCJustice
Transaction Locator: TxLocator1
Appointment Start: Block 10
Appointment Expiry: Block 500
Minimum Dispute Period: 50 blocks
Signature by PISA: σPISA
TxLocator1 & ENCJustice
Signed Receipt
PISA (Monitor) @ Scaling Bitcoin ‘19
Leaning
Watch Tower
In-depth Signed Receipt
Encrypted Justice: ENCJustice
Transaction Locator: TxLocator1
Appointment Start: Block 10
Appointment Expiry: Block 500
Minimum Dispute Period: 50 blocks
Signature by PISA: σPISA
TxLocator1 & ENCJustice
Signed Receipt
BONUS POINTS - Fair real-time payments
We can use a simple HTLC transfer to guarantee fair exchange of signed receipt + payment over the lightning network.
Just put H(R) in receipt and PISA reveals “R” to redeem HTLC payment.
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
...
...
Bob wins
Block 110
Scenario
Bob triggered a dispute,
PISA failed to respond,
Bob gets the coins.
How can Alice prove wrongdoing?
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
...
...
Bob wins
Block 110
In-depth Signed Receipt
Encrypted Justice: ENCJustice
Transaction Locator: TxLocator1
Appointment Start: Block 10
Appointment Expiry: Block 500
Minimum Dispute Period: 50 blocks
Signature by PISA: σPISA
Anyone can verify the “dispute details” via blockchain:
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
...
...
Bob wins
Block 110
In-depth Signed Receipt
Encrypted Justice: ENCJustice
Transaction Locator: TxLocator1
Appointment Start: Block 10
Appointment Expiry: Block 500
Minimum Dispute Period: 50 blocks
Signature by PISA: σPISA
Anyone can decrypt ENCJustice and verify:
Monitor (Tadge) @ Scaling Bitcoin ‘16
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
...
...
Bob wins
Block 110
Reputational Accountability, not Financial
Publicly verifiable that PISA accepted the job and failed to do its duty by the customer.
With a consensus upgrade, the evidence of SPV proof for dispute + Bob’s spend transaction, could be used to slash/refund customer.
Monitor (Tadge) @ Scaling Bitcoin ‘16
Reputational Accountability, not Financial
Publicly verifiable that PISA accepted the job and failed to do its duty by the customer.
With a consensus upgrade, the evidence of SPV proof for dispute + Bob’s spend transaction, could be used to slash/refund customer.
Leaning
Watch Tower
State 1
...
Block 10
Block 11
TxLocator1:ENCJustice
TxLocator2:ENCJustice
TxLocator3:ENCJustice
TxLocator4:ENCJustice
TxLocator5:ENCJustice
TxLocator6:ENCJustice
TxLocator7:ENCJustice
...
...
Bob wins
Block 110
Let’s look at the good, bad and the ugly
PISA - THE GOOD
Leaning
Watch Tower
Channel-Privacy
By re-using the Monitor protocol, PISA doesn’t know what channel is being watched!
Simple Protocol
Adopting a signed receipt for different channel constructions is relatively straight-forward.
Accountability
We can prove to anyone that a PISA-tower cheated.
PISA - THE GOOD, BAD
Leaning
Watch Tower
Channel-Privacy
By re-using the Monitor protocol, PISA doesn’t know what channel is being watched!
Simple Protocol
Adopting a signed receipt for different channel constructions is relatively straight-forward.
O(1) OR O(N) Storage
Depends on the underlying channel construction (or if ENCJustice is stored on-chain via OUTPOST)
Security Deposit hard
While there is “skin in the game”, it may be under-collateralised. Provisions (2015) can help.
Accountability
We can prove to anyone that a PISA-tower cheated.
PISA - THE GOOD, BAD, AND THE UGLY
Leaning
Watch Tower
Channel-Privacy
By re-using the Monitor protocol, PISA doesn’t know what channel is being watched!
Simple Protocol
Adopting a signed receipt for different channel constructions is relatively straight-forward.
O(1) OR O(N) Storage
Depends on the underlying channel construction (or if ENCJustice is stored on-chain via OUTPOST)
Security Deposit hard
While there is “skin in the game”, it may be under-collateralised. Provisions (2015) can help.
Accountability
We can prove to anyone that a PISA-tower cheated.
Consensus Upgrade
We need a new OP_CODE for the slashing condition. Very likely, will not get into Bitcoin soon.
Watching Networks
for Bitcoin (no forks)
Watching Networks
for Bitcoin (no forks)
Channel-Privacy
By re-using the Monitor protocol, PISA doesn’t know what channel is being watched!
O(N) Storage/Updates
Depends in Monitor or Outpost. O(N) implies we need N-1 encrypted blobs, so it leaks number of transfers.
No financial deterrent
No way for the blockchain to self-enforce that via slashing.
Reputation Accountability via Signed Receipt
We can prove to anyone that a PISA-tower cheated.
Watching Networks
for Bitcoin (no forks)
Channel-Privacy
By re-using the Monitor protocol, PISA doesn’t know what channel is being watched!
O(N) Storage/Updates
Depends in Monitor or Outpost. O(N) implies we need N-1 encrypted blobs, so it leaks number of transfers.
No financial deterrent
No way for the blockchain to self-enforce that via slashing.
Reputation Accountability via Signed Receipt
We can prove to anyone that a PISA-tower cheated.
TX + State Intertwined
== bumping fee is HARD
PISA can’t sign state & broadcast it, must get a “pre-signed” justice tx.
Fair exchange payment + job via offchain tx
PISA can be hired via the lightning network. Not knowing which channel hired it.
Watching Networks
for Bitcoin (no forks)
Channel-Privacy
By re-using the Monitor protocol, PISA doesn’t know what channel is being watched!
Simple Protocol
Encrypting and decrypting blobs is straight forward, but reducing O(N) storage “constant” is ugly.
O(N) Storage/Updates
Depends in Monitor or Outpost. O(N) implies we need N-1 encrypted blobs, so it leaks number of transfers.
No financial deterrent
No way for the blockchain to self-enforce that via slashing.
Reputation Accountability via Signed Receipt
We can prove to anyone that a PISA-tower cheated.
TX + State Intertwined
== bumping fee is HARD
PISA can’t sign state & broadcast it, must get a “pre-signed” justice tx.
Fair exchange payment + job via offchain tx
PISA can be hired via the lightning network. Not knowing which channel hired it.
Responder, not trigger
We CANNOT trigger any disputes! Only respond if the counterparty tries to cheat.
Consensus upgrades required
A lot of problems can be fixed. We, as a community, must seriously consider them.
No Verifiable Jobs
(May store junk)
Important that PISA is paid up-front for storing “blobs” and not via bounties.
PISA - WHERE ARE WE NOW?
Signed Receipt BOLT
Coming soon to a wallet near you!
(after guinea pigs try out our demo!)
Encrypted Justice: ENCJustice
Transaction Locator: TxLocator1
Appointment Start: Block 10
Appointment Expiry: Block 500
Minimum Dispute Period: 50 blocks
Cipher + Hash Function: AES-ACM & SHA256
Signature by PISA: σPISA
PRIVATE TEST
Thanks to a heroic effort by Sergi Delgado (speaker yesterday), we have a working basic PISA implementation.
Do you want to try out our watch tower?
Please contact us!
PISA - Final word about “watchers” and their emerging role
Financial Liability & Insurance
Watchers take on the “financial liability” for users who go offline.
The “cost” of a watcher is some function of financial liability, number of updates & number of channels watched.
What can a watch tower do?
Protect hubs against crashes + dos attacks by responding to malicious customer closures
What can a watch tower NOT do?
Protect hubs against insider threats, theft of signing keys, etc.
Responder of LAST resort
PISA - Final word about “watchers” and their emerging role
Payment channel hubs
Customers generally trust hubs (we see this today), but for hubs, all their coins are “effectively” in a hot wallet and every customer is an adversary.
Routing Nodes
Peers will open channels with anyone to search out popular routes / best fees. They WON’T know or trust their counterparty.
Settlement System and
Root of Trust of all Layer 2
Plasma Group
PisaResearch
paddypisa
https://pisa.watch