A computer-implemented method for performing an off-chain transaction, the computer-implemented method comprising: attaching, by a first entity (402, 702), a digital asset (406, 706, 1206) to an exchange platform (408, 704, 1204); computing a first shared key (410, 710) using a key associated with the first entity (402, 702) and a first key associated with the exchange platform (408, 704, 1204); causing a first blockchain transaction to be recorded to a blockchain by at least: generating the first blockchain transaction to be unlockable by any computer system having access to the first shared key, wherein the first blockchain transaction pays out from the digital asset (406, 706, 1206); and broadcasting the first blockchain transaction to a blockchain network; transferring, by the first entity (402, 702), ownership of the digital asset attached to the exchange platform (408, 704, 1204) from the first entity to a second entity (714, 1202); causing a second blockchain transaction to be recorded to the blockchain by at least: computing a second key associated with the exchange platform (408, 704, 1204) using a key associated with the second entity (714, 1202); computing a second shared key using the key associated with the second entity (714, 1202) and the second key associated with the exchange platform (408, 704, 1204), wherein the second shared key is equal to the first shared key; and replacing the first key associated with the exchange platform (408, 704, 1204) with the second key associated with the exchange platform (408, 704, 1204); and detaching, by the second entity (714, 1202), the digital asset from the exchange platform using the second shared key if it is determined that the second entity (714, 1202) is the current owner of the digital asset (406, 706, 1206). attaching, by a first entity (402, 702), a digital asset (406, 706, 1206) to an exchange platform (408, 704, 1204); computing a first shared key (410, 710) using a key associated with the first entity (402, 702) and a first key associated with the exchange platform (408, 704, 1204); causing a first blockchain transaction to be recorded to a blockchain by at least: generating the first blockchain transaction to be unlockable by any computer system having access to the first shared key, wherein the first blockchain transaction pays out from the digital asset (406, 706, 1206); and broadcasting the first blockchain transaction to a blockchain network; generating the first blockchain transaction to be unlockable by any computer system having access to the first shared key, wherein the first blockchain transaction pays out from the digital asset (406, 706, 1206); and broadcasting the first blockchain transaction to a blockchain network; transferring, by the first entity (402, 702), ownership of the digital asset attached to the exchange platform (408, 704, 1204) from the first entity to a second entity (714, 1202); causing a second blockchain transaction to be recorded to the blockchain by at least: computing a second key associated with the exchange platform (408, 704, 1204) using a key associated with the second entity (714, 1202); computing a second shared key using the key associated with the second entity (714, 1202) and the second key associated with the exchange platform (408, 704, 1204), wherein the second shared key is equal to the first shared key; and replacing the first key associated with the exchange platform (408, 704, 1204) with the second key associated with the exchange platform (408, 704, 1204); and computing a second key associated with the exchange platform (408, 704, 1204) using a key associated with the second entity (714, 1202); computing a second shared key using the key associated with the second entity (714, 1202) and the second key associated with the exchange platform (408, 704, 1204), wherein the second shared key is equal to the first shared key; and replacing the first key associated with the exchange platform (408, 704, 1204) with the second key associated with the exchange platform (408, 704, 1204); and detaching, by the second entity (714, 1202), the digital asset from the exchange platform using the second shared key if it is determined that the second entity (714, 1202) is the current owner of the digital asset (406, 706, 1206).