A computer implemented method of performing an exchange of entities between a first user and a second user, the method comprising: receiving, from a first user, a first invitation to perform the exchange, the first invitation comprising a first set of metadata associated with the invitation, wherein the first set of metadata comprises an indication of entities to be exchanged and a first set of conditions for the exchange; generating a first redeem script, the first redeem script comprising: the first set of metadata, a first user public key (P1A) associated with the first user, wherein the first user public key (P1A) is a cryptographic pair with a first user private key (V1A), and a first third-party public key (P1T) associated with a first third-party, wherein the first third-party public key (P1T) is a cryptographic pair with a first third-party private key (V1T); hashing the first redeem script to generate a first script hash; generating a first invitation transaction (Tx) comprising an output (UTXO) associated with: i) an encrypted, electronically transferrable digital asset; and ii) the first script hash wherein the first script hash is provided within the first invitation transaction (Tx) and wherein the first set of metadata is embedded in a place in the redeem script for a public key sending, over a first network, the first redeem script and the first script hash; and sending, over a second network, the first invitation transaction for inclusion on a peer-to-peer (P2P) distributed ledger. receiving, from a first user, a first invitation to perform the exchange, the first invitation comprising a first set of metadata associated with the invitation, wherein the first set of metadata comprises an indication of entities to be exchanged and a first set of conditions for the exchange; generating a first redeem script, the first redeem script comprising: the first set of metadata, a first user public key (P1A) associated with the first user, wherein the first user public key (P1A) is a cryptographic pair with a first user private key (V1A), and a first third-party public key (P1T) associated with a first third-party, the first set of metadata, a first user public key (P1A) associated with the first user, wherein the first user public key (P1A) is a cryptographic pair with a first user private key (V1A), and a first third-party public key (P1T) associated with a first third-party, wherein the first third-party public key (P1T) is a cryptographic pair with a first third-party private key (V1T); hashing the first redeem script to generate a first script hash; generating a first invitation transaction (Tx) comprising an output (UTXO) associated with: i) an encrypted, electronically transferrable digital asset; and ii) the first script hash wherein the first script hash is provided within the first invitation transaction (Tx) and wherein the first set of metadata is embedded in a place in the redeem script for a public key i) an encrypted, electronically transferrable digital asset; and ii) the first script hash wherein the first script hash is provided within the first invitation transaction (Tx) and wherein the first set of metadata is embedded in a place in the redeem script for a public key sending, over a first network, the first redeem script and the first script hash; and sending, over a second network, the first invitation transaction for inclusion on a peer-to-peer (P2P) distributed ledger.