Any NFT, provided that its contract is compatible with the NFT standard in the TON blockchain, can be signed thanks to the mechanism described in White Paper. A user registered on our web portal can both sign other users' NFTs and accept other users' signatures on his/her own NFTs. To reliably verify a user as a signatory, it is enough to non-custodially bind a user’s wallet and login of any social network to the web portal.

A user-signatory sends a request to sign someone's NFT (so-called pull scheme of signing, see White Paper). Upon request, there created a special smart contract – a signature entity in the TON blockchain. On the next stage, a special transaction from the NFT owner to the signature contract going through the NFT contract verifies the signature. Thus, in order to get someone's signature on your NFT, it is necessary first to wait until his/her action and then confirm the signature.

In another signing scheme, the NFT owner through the web portal opens it for someone to sign (the so-called pull scheme of signing, see White Paper). Upon request, there created a special smart contract – a signature entity in the TON blockchain. After that, any transaction with a comment from the signatory for this smart contract will verify his/her signature on the given object. Thus, in order to get someone's signature on your NFT, it is necessary first to consciously open it for him/her to sign and then wait until his/her consent.

Why shouldn't a simple transaction from the signatory's wallet to an NFT address be considered a signature? Firstly, the transaction history of any smart contract can be spammed with microtransactions, so it will be rather difficult to detect a real signature. Secondly, the object to-sign itself should include a lot of additional information like the date, the linked social net account, perhaps a graphical representation of the signature, etc. Finally, it is conceptually more correct and formal to store each signature in a dedicated smart contract.