Method and system for integration of market exchange and issuer processing for blockchain-based transactions

A method for authorization of a blockchain transaction, comprising:

• storing, in an account database of a processing server, a plurality of account profiles, wherein each account profile includes data related to a consumer including at least an account identifier, a fiat currency amount, and one or more blockchain currency amounts, each blockchain currency amount being associated with a blockchain network;
• receiving, by a receiving device of the processing server, via a payment network, a transaction message for a payment transaction, wherein the transaction message is formatted based on one or more standards and includes a plurality of data elements, including a first data element configured to store a personal account number that includes a specific account identifier and a second data element reserved for private use that includes at least a network identifier corresponding to a blockchain network and a transaction amount;
• identifying, by a processing device of the processing server, a specific account profile stored in the account database where the included account identifier corresponds to the specific account identifier included in the first data element of the received transaction message;
• identifying, by the processing device of the processing server, a risk value for the payment transaction, wherein the risk value is based on at least the transaction amount included in the second data element of the received transaction message and a combination of:
• the fiat currency amount and a blockchain currency amount associated with the blockchain network corresponding to the network identifier included in the second data element of the received transaction message included in the identified specific account profile;
• determining, by the processing device of the processing server, authorization of the payment transaction based on at least the identified risk value;
• modifying, by the processing device of the processing server, the received transaction message based on the authorization determination;
• and
• transmitting, by a transmitting device, the modified transaction message.