Secure data exchange

A method and system of exchanging first valuable data at a first node for second valuable data at a second node. The first node sends a plurality of messages to the second node, the messages blinded by a first encryption and with the first valuable data concealed in one message. The second node applies another encryption to create a plurality of double-blinded messages and sends them to the first node. The first node removes the encryption it originally applied and sends the partially decrypted blinded messages back to the second node. The second node follows the same process for the second valuable data it wishes to send to the first node. The valuable data may be a shared password or form part of a PAKE protocol. The invention provides a stochastic fair exchange of data without a trusted third party such that a man-in-the-middle attack by a malicious third party may be prevented.