Continuum

#[ink::contract]
mod data_access {
    use ink::storage::Mapping;

    #[ink(storage)]
    pub struct DataAccess {
        requests: Mapping<u64, Request>,
        next_id: u64,
    }

    impl DataAccess {
        #[ink(message)]
        pub fn request_access(
            &mut self,
            customer: AccountId,
            fields: Vec<String>,
            duration: u64,
            payment: Balance
        ) -> u64 {
            // Record request on-chain
            let id = self.next_id;
            self.requests.insert(id, &Request {
                customer,
                organization: self.env()
                    .caller(),
                fields,
                duration,
                payment,
                status: Pending,
            });
            self.next_id += 1;
            id
        }

        #[ink(message)]
        pub fn approve(&mut self, id: u64) {
            // Cryptographic verification
            // Escrow payment
            // Grant access
        }
    }
}