Abstract: A system supports symmetric release of cryptologically-locked asset transactions. A leading exchange party and a reciprocal exchange party establish, at least in part, a peer challenge in a pre-exchange proposal. The reciprocal party uses the peer challenge to lock a cryptologically-locked asset transaction. The solution to the peer challenge corresponds to an exchange key controlled by the leading exchange party. After establishment of the cryptologically-locked asset transaction, the leading party may request that exchange logic initiate release of the cryptologically-locked asset transaction. In response to the request, the exchange logic may execute a symmetric release of the exchange key and/or signature to the reciprocal exchange party and cryptologically-locked asset transaction (such that the asset is transferred to the leading exchange party).

Abstract: A system supports symmetric release of cryptologically-locked asset transactions. A leading exchange party and a reciprocal exchange party establish, at least in part, a peer challenge in a pre-exchange proposal. The reciprocal party uses the peer challenge to lock a cryptologically-locked asset transaction. The solution to the peer challenge corresponds to an exchange key controlled by the leading exchange party. The cryptologically-locked asset transaction call for solution of the peer challenge and signature of the transaction by exchange logic as conditions of release of the cryptologically-locked asset transaction. The exchange logic may execute a symmetric release of the exchange key and/or signature to the reciprocal exchange party and cryptologically-locked asset transaction (such that the asset is transferred to the leading exchange party).

Abstract: A system supports symmetric release of cryptologically-locked asset transactions. A leading exchange party and a reciprocal exchange party establish, at least in part, a peer challenge in a pre-exchange proposal. The reciprocal party uses the peer challenge to lock a cryptologically-locked asset transaction. The solution to the peer challenge corresponds to an exchange key controlled by the leading exchange party. After establishment of the cryptologically-locked asset transaction, the leading party may request that exchange logic initiate release of the cryptologically-locked asset transaction. In response to the request, the exchange logic may execute a symmetric release of the exchange key and/or signature to the reciprocal exchange party and cryptologically-locked asset transaction (such that the asset is transferred to the leading exchange party).

Abstract: A system supports symmetric release of cryptologically-locked asset transactions. A leading exchange party and a reciprocal exchange party establish, at least in part, a peer challenge in a pre-exchange proposal. The reciprocal party uses the peer challenge to lock a cryptologically-locked asset transaction. The solution to the peer challenge corresponds to an exchange key controlled by the leading exchange party. The cryptologically-locked asset transaction call for solution of the peer challenge and signature of the transaction by exchange logic as conditions of release of the cryptologically-locked asset transaction. The exchange logic may execute a symmetric release of the exchange key and/or signature to the reciprocal exchange party and cryptologically-locked asset transaction (such that the asset is transferred to the leading exchange party).

Abstract: A payment system for use with electronic payment devices. Electronic payment cards (e.g. "Smart Cards"), may be used with one or more payment stations (e.g. electronic cash registers). The payment stations are designed for receiving, during a payment transaction, a monetary value by crediting, in the payment station, a first value, and debiting, in the payment means, a second value corresponding to the first value. The first and second values may be expressed in different calculation units, such as currencies of different countries. The system furthermore offers a payment device for application in such a system, and a method for effecting a payment transaction with an electronic payment means.

Abstract: A method of securely storing and retrieving monetary values, such as electronic checks and electronic coins. In an interactive protocol between an issuer (e.g., a bank terminal) and a recipient (e.g., a smart card) of electronic money, authentication values (A, B, . . .) are produced by the issuer and are stored in an external storage device (e.g., an electronic wallet). At a later stage, the protocol is repeated between the recipient and the storage to securely retrieve the stored authentication values.

Abstract: The invention relates to a method for tracing payment data in an anonymous payment system having electronic payment means, such as so-called "smart cards". According to the invention, the user commits himself to a value (w) which may later be used for the tracing by a payment institution. The value (w) is preferably recorded with the help of a so-called one-way function (F) and an (electronic) signature (.sigma.), so that the payment institution does not dispose of the value itself, but is able to verify it on the basis of the stored derivative (w") of the value. The invention further relates to a payment means and a payment system for application of the method.