There are a few replies to this question on Bitcoin Stackexchange:
https://bitcoin.stackexchange.com/questions/23893/what-are-the-limits-of-m-and-n-in-m-of-n-multisig-addresses/28104#28104
(linking to my reply, but other ones are also interesting)
Topic: Multi-sig transactions with more than three signers? (Read 907 times)
@xrobesx: This question has been been answered so many times here. Have you searched at all?
Am I right that Bitcoin is capped at 3 multi-sig signers or is it possible to do multi-sig with more than 3 signers?
Maybe even something external to source code like 3 groups of 3 signers all sign together and create their own key, meaning you'd need 9 signers.. or something like this? I'm guessing no, but just wondering.
Thanks.
Maybe even something external to source code like 3 groups of 3 signers all sign together and create their own key, meaning you'd need 9 signers.. or something like this? I'm guessing no, but just wondering.
Thanks.
how do you set up multi-sigs within bitcoin?
The opcode allows up to 20 signers (i.e. 20-of-20). So for native multisig (not commonly used over P2SH) you can create a 20 of 20 transaction. Native multisig larger than 3 of 3 are valid but not "standard" and thus won't be relayed by most nodes.
For P2SH however, the entire script must not exceed 520 bytes. This effectively limits you to 15 of 15 multisig (7 of 7 if using uncompressed keys). See 520 byte limit. For the tx to be "Standard" the ScriptSig must be less than 500 bytes so that limits you to 7 signatures (i.e. 7 of 15 or 7 of 7). A larger "m" (i.e. 8 of 15) is still valid but it isn't standard and won't be relayed by most nodes.
FRIENDLY WARNING: With P2SH it is possible (actually easy) to create an invalid (unspendable) script. Since the address is a hash of the script and the script it unknown to the network, the network has no way to validate the script at the time of funding. You can fund an address which ultimately is unspendable. Always test on testnet.
For P2SH however, the entire script must not exceed 520 bytes. This effectively limits you to 15 of 15 multisig (7 of 7 if using uncompressed keys). See 520 byte limit. For the tx to be "Standard" the ScriptSig must be less than 500 bytes so that limits you to 7 signatures (i.e. 7 of 15 or 7 of 7). A larger "m" (i.e. 8 of 15) is still valid but it isn't standard and won't be relayed by most nodes.
FRIENDLY WARNING: With P2SH it is possible (actually easy) to create an invalid (unspendable) script. Since the address is a hash of the script and the script it unknown to the network, the network has no way to validate the script at the time of funding. You can fund an address which ultimately is unspendable. Always test on testnet.
I believe the cap is at 5 signatures. I've done 4 without any problem before.
Am I right that Bitcoin is capped at 3 multi-sig signers or is it possible to do multi-sig with more than 3 signers?
Maybe even something external to source code like 3 groups of 3 signers all sign together and create their own key, meaning you'd need 9 signers.. or something like this? I'm guessing no, but just wondering.
Thanks.
Maybe even something external to source code like 3 groups of 3 signers all sign together and create their own key, meaning you'd need 9 signers.. or something like this? I'm guessing no, but just wondering.
Thanks.
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