Rearrangement Attack Visualization for Plasma Cash

Transcript

1. Time sequential visualization of rearrangement attack on Plasma Cash as preparation of Dan Robinson's Simple Exit Game Rearrangement Attack cryptoeconomicslab sg
2. tx1->tx2->(-Tx3)->tx4 Tx1 103 blkNum Alice Box means TxNetto(Tx w/o sign) - UTXO can be input & output - Malicious actor can use any UTXO w/o sign
3. Tx1 Tx2 103 blkNum 265 Alice Bob tx1->tx2->(-Tx3)->tx4 Arrow means *valid spending* - A coin belongs to right blockHeight - "What is Parent Tx?" was a big question
4. Tx1 Tx2 -Tx3 103 blkNum 265 400 Alice Bob Mallory(op) tx1->tx2->(-Tx3)->tx4 Invalid History Tx is to be included in block as preparation of attack w/o Bob's sign
5. Tx1 Tx2 Tx4 -Tx3 103 blkNum 265 765 400 Alice Bob Carl Mallory(op) tx1->tx2->(-Tx3)->tx4 by Mallory Operator intentionally withholds Carl's Tx4
6. Tx1 Tx2 Tx4 -Tx3 103 blkNum 265 765 400 Alice Bob Carl Mallory(op) exiting state t=0 by Mallory tx1->tx2->(-Tx3)->tx4 Mallory exits invalid history Tx Oddly Carl can't challenge because of absence of proof
7. Tx1 Tx2 Tx4 -Tx3 103 blkNum 265 765 400 Alice Bob Carl Mallory(op) challenged state challengeBefore state t < period/2 by Bob tx1->tx2->(-Tx3)->tx4 Bob only is able to challenge that
8. Tx1 Tx2 Tx4 -Tx3 103 blkNum 265 765 400 Alice Bob Carl Mallory(op) responded state challengeBefore state respondChallenge state by Mallory tx1->tx2->(-Tx3)->tx4 period/2 < t < period Mallory publish proof
 - Bob & Carl finally see Tx4 - exit game continued - Tx3 is still exitable Mallory aims to publish proof at (period - 1sec) Mallory can invalidate Bob's challenge via publishing Carl's proof
9. Tx1 Tx2 Tx4 -Tx3 103 blkNum 265 765 400 Alice Bob Carl Mallory(op) challenged state challengeBefore state by Carl period < t maybe tx1->tx2->(-Tx3)->tx4 Because of Mallory's griefing Carl's challengeBefore doesn't prevent Tx3 to be exited