The invention provides improved methods and corresponding systems for the sharing, storage, creation and accessing of data stored on a blockchain eg the Bitcoin blockchain. It may form part of a protocol for searching the blockchain for content/data. A method in accordance with the invention may be used for associating or linking data stored within (separate/different) blockchain transactions to enable the identification, retrieval and/or sharing of data stored therein. Additionally, or alternatively, it facilitates identification of transactions (TX) in a blockchain which store content/data that needs to be shared, transmitted, stored and/or accessed by a user. Such a method comprises the step of mapping a mnemonic to: 1) a public key (PK) associated with the transaction (TX); and 2) the transaction ID (TXID) of the transaction (TX).