Transferring self-custodied cryptocurrency tokens using marketplaces

A method, comprising:

• determining that a first amount of a cryptocurrency has been transferred to a marketplace wallet address from a first user wallet address that is hosted on a first type of blockchain technology;
• accessing a listing ledger to determine an amount of the cryptocurrency specified in a listing of a non-fungible token (NFT), wherein the listing ledger stores at least one of an indication of the first amount of the cryptocurrency, an NFT identifier, an NFT smart contract wallet address, a user wallet address associated with a seller, a minimum bid for the NFT, or an initial bid for the NFT;
• sending a cryptographic challenge to a user device that submitted the listing, the cryptographic challenge being encrypted with a public key;
• receiving an unencrypted challenge from the user device including a signature generated by a private key that is associated with the public key;
• determining that the listing is valid based at least in part on receiving the unencrypted challenge;
• determining, based at least in part on determining that the listing is valid, that the first amount of the cryptocurrency matches the amount of the cryptocurrency specified in the NFT;
• in response to determining that the first amount of the cryptocurrency has been transferred to the marketplace wallet address and a determination that the first amount of the cryptocurrency matches the amount of the cryptocurrency specified in the listing of the NFT, invoking a transfer function provided by a non-fungible token (NFT) smart contract, wherein the transfer function causes ownership of a non-fungible token (NFT) managed by the NFT smart contract to be transferred to a specified user wallet address;
• and
• in response to the NFT being transferred to the specified user wallet address, utilize a bridge to wrap a second amount of the cryptocurrency from the marketplace wallet address and send the second amount of the cryptocurrency to a second user wallet address that is hosted on a second type of blockchain technology, wherein wrapping the second amount of the cryptocurrency enables the second amount of the cryptocurrency to be compatible on the second type of blockchain technology.

A non-transitory, computer-readable medium, comprising machine readable instructions that, when executed by a processor of a computing device, cause the computing device to at least:

• determine that a first amount of a cryptocurrency has been transferred to a marketplace wallet address from a first user wallet address that is hosted on a first type of blockchain technology;
• accessing a listing ledger to determine an amount of the cryptocurrency specified in a listing of a non-fungible token (NFT), wherein the listing ledger stores at least one of an indication of the first amount of the cryptocurrency, an NFT identifier, an NFT smart contract wallet address, a user wallet address associated with a seller, a minimum bid for the NFT, or an initial bid for the NFT;
• sending a cryptographic challenge to a user device that submitted the listing, the cryptographic challenge being encrypted with a public key;
• receiving an unencrypted challenge from the user device including a signature generated by a private key that is associated with the public key;
• determining that the listing is valid based at least in part on receiving the unencrypted challenge;
• determining, based at least in part on determining that the listing is valid, that the first amount of the cryptocurrency matches the amount of the cryptocurrency specified in the NFT;
• in response to a determination that the first amount of the cryptocurrency has been transferred to the marketplace wallet address and a determination that the first amount of the cryptocurrency matches the amount of the cryptocurrency specified in the listing of the NFT, invoke a transfer function provided by a non-fungible token (NFT) smart contract, wherein the transfer function causes ownership of a non-fungible token (NFT) managed by the NFT smart contract to be transferred to a specified user wallet address;
• and
• in response to the NFT being transferred to the specified user wallet address, utilize a bridge to wrap a second amount of the cryptocurrency from the marketplace wallet address and send the second amount of the cryptocurrency to a second user wallet address that is hosted on a second type of blockchain technology, wherein wrapping the second amount of the cryptocurrency enables the second amount of the cryptocurrency to be compatible on the second type of blockchain technology.