$320M Hack of Liquid Network via SideSwap.io
Never a dull day in Bitcoin.
UPDATE
The purported white-hat hacker communicated with Blockstream through Bitcoin OP_RETURN messages and PGP-encrypted text. In a message at block 965,875, the party told Blockstream to “fix the bug first” and ensure every node is patched before transferring the funds back.
Adam Back-led Blockstream subsequently sent a PGP-signed onchain message saying, “Bridge nodes are patched, safe to return the funds.” The signature verifies against the security key published on Blockstream’s website. The roughly 4,000 BTC remained in the attacker’s wallet at the time of publication.
The exchange followed an earlier message from the attacker offering to send most of the bitcoin back to the federation address. Blockstream had first contacted the party through a transaction at block 965,822, asking it to contact the company’s security team.
Communication between the parties began after Liquid said on Sept. 6 that roughly 4,000 BTC, then worth about $320 million, had been withdrawn from its federation wallet. The funds were withdrawn through the SideSwap Peg-out Authorization Key, but that key itself was not compromised, according to the network.
In a statement on X, SideSwap said the affected transaction involved 4,000 L-BTC sent to its peg-out service. The service burned the tokens using a valid peg-out authorization, after which the Liquid Federation paid 3,996 BTC to the customer’s Bitcoin address.
Blockstream later established that the L-BTC had been created through a bug in the Elements software, according to SideSwap. The trading platform said neither its systems nor its peg-out authorization key had been compromised.
Meanwhile, Liquid has paused network activity, with bridge nodes disabled and LBTC deposits and withdrawals suspended at exchanges. SideSwap said swaps, peg-ins, and peg-outs remain paused until the network resumes.
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UPDATE
Blockstream ”paused” the Liquid Bitcoin network. Turned off. That’s a big difference between Bitcoin and Liquid Bitcoin
The discussion between @npub1jg55...6n8n and the white-hat hacker (WHH) regarding the ~4000 BTC from @Liquid_BTC is happening in public. It seems to be their preference over email. As it's hard to follow the chain of messages in OP_RETURN, here's a summary with links.
11:30 AM PDT - WHH: "we are whitehats. contact us on chain"
mempool.space/tx/c103de95817…
12:31 PM PDT - Blockstream: "Please contact security@npub1jg55...6n8n.com"
mempool.space/tx/91271efcbb5…
6:49 PM PDT - Blockstream: [encrypted to hacker's key, PGP-signed by security@npub1jg55...6n8n.com]
mempool.space/tx/bd81219691e…
7:20 PM PDT - WHH: "sending most back to bc1qdlld6antmv4xug242ed83q7k4rqw50cwfns38szx4qu2f4jwaxxsuhwxxr, is that ok"
mempool.space/tx/3a3eac4a263…
8:27 PM PDT - WHH: "Please fix the bug first. The chain is under risk at latest commit right now. Make sure every node is patched. Then we will transfer the money back safely after confirming the fix." [+ PGP-encrypted details to Blockstream]
mempool.space/tx/83825b2135d…
8:30 PM PDT - Blockstream: "Yes, thank you." (PGP-signed; answers the 7:20 question, not the 8:27 one — confirmed in the same block)
mempool.space/tx/8a444eed65c…
Status as of 9:12 PM PDT: ~3,998.5 BTC still unmoved, no further messages from either side.
Hacker address: mempool.space/address/bc1ql4…
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On September 6, 2026, approximately 3,996 BTC (~$320 million) was withdrawn from the Liquid Network’s federation reserves in a single transaction, draining roughly 95% of the network’s Bitcoin backing. The actors left an on-chain message claiming to be “whitehats.”
September 6, 2026, around 1406–1428 UTC
Amount
~3,996 BTC (~$319–320M), leaving only ~207 BTC in reserve
Mechanism
Executed via SideSwap’s Peg-out Authorization Key (PAK)
Key Compromised?
No. Liquid explicitly stated neither the SideSwap PAK nor any other keys were compromised
On-chain message
"we are whitehats. contact us on chain" embedded in an OP_RETURN output
Network status
Liquid paused — bridge nodes disabled, no new transactions being submitted
L-BTC backing
A matching amount of L-BTC was burned in the same operation, so remaining circulating L-BTC remains ~11 backed by the reduced reserve
How It Happened (What We Know)
Liquid Network operates on a Strong Federation model 15 functionary members collectively control the Bitcoin reserves via an 11-of-15 multisig. To withdraw BTC back to the mainchain, a Peg-out Authorization Key (PAK) is required. PAKs are designed as a safeguard so that even if functionaries are compromised, funds can only go to pre-approved (whitelisted) addresses.
The critical mystery the SideSwap PAK was used legitimately (not stolen), yet the funds went to a brand-new, non-whitelisted address. This suggests the failure was not a stolen key, but rather a breakdown elsewhere in the operational or authorization chain — possibly insider action, a compromised functionary process, or a flaw in how the PAK was configured or approved. Blockstream has not yet explained how a valid PAK directed funds to an unapproved destination.
The “White Hat” Claim
The actors sent 0.00001 BTC back to Liquid’s own address and asked to be contacted on-chain. Blockstream has responded with signed on-chain messages attempting to open communication, but as of now, the white-hat claim is unverified and the bulk of the funds (~3,998 BTC) have not moved since.
Industry security figures are skeptical. Ledger CTO Charles Guillemet noted that genuine white-hat hackers do not typically drain 95% of a bridge’s reserves while soliciting contact — a pattern more consistent with theft framed retroactively as a security demonstration.
Current Impact
Exchanges have halted L-BTC deposits and withdrawals.
Other Liquid assets (USDT, DePix, real-world assets) were not affected.
Users cannot currently transact on the Liquid sidechain until federation members resolve the incident and restore operations.
Bottom line The $320M withdrawal is confirmed. Whether this is a genuine white-hat rescue, an insider exploit, or a social-engineering attack on the federation’s operational controls remains unresolved. The funds are sitting visible on-chain, but have not been returned.
Will this be the final straw in Blockstream the company? Only time will tell, but I expect more scandals to come.








Full post-mortem:
