Mara's Slipstream service is basically a non-public mempool that charges a surplus (compared to the normal public mempool fee market) to collect transactions that will become confirmed in one of Mara's next mined blocks. Transactions sent to Slipstream are NOT broadcasted to other nodes. They remain hidden from public until their attached feerate justifies to be mined in a block by Mara's mining pool.

Mara is a stock listed company to my knowledge and they would be stupid to spoil and stain their Slipstream service. Slipstream is to my knowledge the only such easily accessible public service which allows to mine non-standard and/or non-public transactions.

It's possible that other major mining pools also offer similar services, but contrary to Mara's Slipstream, they don't seem to be public. You would have to find a contact at some other reasonably large mining pool, negotiate terms and extra fees, trust they don't screw you to have them mine a transaction of yours hidden from public.

So far IIRC we have only two samples mined safely by Slipstream service of Mara, namely puzzle #67 and #68 withdrawals.
Puzzle #67 withdrawal transaction 0be77ec8...46e32986 has Audit "Not seen in Mempool" where mempool.space clearly indicates that this transaction wasn't seen in public before it was actually confirmed in a block, here of course mined by Mara.

Same is for puzzle #68 withdrawal transaction a5635eb2...88b0eb08, mempool.space's Audit is again "Not seen in Mempool", i.e. hidden from public mempools.

With unconditional FullRBF any public broadcasting of a transaction disclosing the public key of known low entropy private key "secured" funds is suicide for the funds. What some folks here posted like offering a high fee under some stupid conditions only shows one thing: a lack of understanding of consequences of FullRBF in public mempools and how mining works.

Mining blocks is a random process. It's only within larger time frames that blocks are mined in about 10 minutes on average! See the TTM column at https://bitcoinexplorer.org/blocks how variable the temporal distance of blocks is (here TTM is based on the timestamp of the block, not when the block actually was seen by a particular node in the network).


We've seen how the withdrawal of puzzle #69 was likely stolen IIRC, because the team of solvers was stupid enough to ignore so far safe hidden non-public mining via https://slipstream.mara.com.


Bullshit. Fortunately you won't solve any of the remaining puzzles to embarras yourself with a spectacular failure to withdraw a solution.