Proof-of-Reserve

At least monthly, CheckSig provides a public proof that all assets in custody are safe, i.e., still under control. This might seem so obvious to be redundant and, as a matter of fact, no other custodian proves its reserves: woefully, they could be concealing losses that will be only discovered later on.

At CheckSig, we strongly believe in a provably honest transparent custody: check out below our proof-of-reserve transactions and explore them on-chain.

In each transaction we include the amount under custody consolidated in the previous proof-of-reserve, collect all deposits received since then, pay the transaction fee, withdraw according to our clients’ requests, and consolidate the rest as a single amount of Bitcoins. This amount represents the assets under custody at the transaction date; independently, our internal controls and external auditors attest that those assets exceed the obligations we have towards our clients.

Since July 2021, we started to reuse the same consolidation address to make the proof-of-reserve self-contained: CheckSig spends from and, at the same time, to the consolidation address in the same transaction. This spend-to-self transaction proves the ability of spending from the same address that is used to consolidate all assets under custody. The consolidation address might occasionally change in the future; nonetheless, even in that case, the proof-of-reserve will be spending from and to the new address in a spend-to-self transaction. While address reuse is very bad for privacy, it is fine in our case because the proof-of-reserve must be public. Moreover, residual security concerns (e.g., nonce exfiltration) are solved by our multi-level multi-signature scheme using Hardware Security Modules from different vendors (to learn more about our security, read about CheckSig custody protocol).

The current consolidation address is bc1qqst9un5sz8576fy2nnqkpm4rpfh0weveqwtt8zxgjp02g2mx5q7s2vresu.

Transaction Block Deposits Fee Withdrawal Asset Under Custody
Jul 2, 2021 689351 32.06748252 0.00051181 0.00000000 173.97055334
Jun 2, 2021 685857 8.95164489 0.00027216 0.00000000 141.90358263
May 1, 2021 681372 7.24822810 0.00030954 0.00000000 132.95220990
Apr 1, 2021 677275 21.21598524 0.00057939 1.00000000 125.70429134
Mar 1, 2021 672666 22.78825901 0.00051181 0.00000000 105.48888549
Feb 2, 2021 668707 0.00000000 0.00004851 0.00000000 82.70113829
Jan 31, 2021 668402 32.07315051 0.00031248 0.00000000 82.70118680
Jan 1, 2021 663972 18.03542688 0.00051181 0.00000000 50.62834877
Dec 2, 2020 659601 12.71367043 0.00073700 0.00000000 32.59343370
Nov 3, 2020 655223 0.00000000 0.00006930 0.00000000 19.88050027
Oct 12, 2020 652363 19.88127787 0.00070830 0.00000000 19.88056957