Introduction
This is Multisign Threshold Crypto https://en.wikipedia.org/wiki/Threshold_cryptosystem and is not Multisig.
Advantages:
- compatibility.
- generally more secure.
- faster and less expensive due to single transaction.
- allow unlimited number of signers theoretically.
- Private Key can be calculated manually with all Signer Keys.
Disadvantages:
- Private Key or all Signer Keys are needed to withdrawl coins from Wallet Address.
- less secure then Multisig, if the Multisig server is completely trustable.
Security Risks
Wallet Address, Private Key, and last Signer Key are never written into file system, but there are still other end-nodes and middleman risks.
Simple Two Signers Example
Buyer and Seller
- Buyer creates Multisign Contract and get Buyer secret Signer Key. Buyer then send the Multisign Contract to Seller.
- Seller receives the Multisign Contract to get Seller secret Signer Key and the Wallet Address. Seller then send the Wallet Address (sometimes also called as Invoice/Bitcoin Address) to Buyer.
- Buyer deposits coins into the Wallet Address. Seller checks the Wallet Address balance and delivers Buyer the product/service.
- If Buyer is satisfied then send Buyer secret Signer Key to Seller.
- Seller gets the Private Key from Buyer and Seller Signer Keys to withdraw coins from the Wallet Address.
Private Key Manual Calculation Example
Three Signer Keys:
- o1x3x2f22831860955426f828a3514d5165d3b5ba8004f800d6d9cc783946e8fda654xed88b7bb
- o2x3x05fef8bc4aa7183755164b7357d3dddbb1ddcdc32e063442bc669139b5111724x4a603047
- o3x3x6fe17d07632d11121cd455e31137a049f359009df812d49b21819b3bc62aa5cexd4c752d1
Stripped three Signer Keys in order:
2f22831860955426f828a3514d5165d3b5ba8004f800d6d9cc783946e8fda654 \
05fef8bc4aa7183755164b7357d3dddbb1ddcdc32e063442bc669139b5111724 \
6fe17d07632d11121cd455e31137a049f359009df812d49b21819b3bc62aa5ce
Private Key is the UTF8 Encoded above in SHA256 Hash:
e3963fa4e0c48109157f095f6155ec7ab617b7c731e56d3fb9ba786da2286d7e