A computer generates a first encrypted message by encrypting an unencrypted message for decryption at a receiving device. The computer couples the first encrypted message with addressing data associated with the receiving device to generate a coupled message. The computer generates a second encrypted message by encrypting the coupled message for decryption at a data transmission service. The computer transmits the second encrypted message via the data transmission service to enable the receiving device to read the unencrypted message.

Embodiments are directed to a computer-implemented method, computer system, and computer program product for creating a public key token. A public key and private key are generated, using a master key. A set of permissions is received for the public key and private key that note the allowable uses for the public key and private key. Thereafter, the set of permissions, encrypted public key, and other associated information is placed in a public key token.

A system for securely computing an elliptic curve scalar multiplication in an unsecured environment, including: a secure processor including secure memory, the secure processor configured to: split a secure scalar K into m.sub.2 random values k.sub.i, where i is an integer index; randomly select m.sub.1−m.sub.2 values k.sub.i for the indices m.sub.2<i≦m.sub.1; select m.sub.1 mask values δ.sub.i; compute m.sub.1 residues c.sub.i based upon random residues a.sub.i, δ.sub.π(i).sup.−1, and k.sub.π(i), wherein π(i) is a random permutation; compute m.sub.1 elliptic curve points G.sub.i based upon random residues a.sub.i and an elliptic point to be multiplied; receive m.sub.1 elliptic curve points; and compute the elliptic curve scalar multiplication by combining a portion of the received elliptic curve points and removing the mask values δ.sub.i from the portion of the received elliptic curve points; a memory device; and a processor in communication with the memory device, the processor being configured to: receive m.sub.1 residues c.sub.i and elliptic curve points G.sub.i; compute m.sub.1 elliptic curve points P.sub.i based upon the m.sub.1 residues c.sub.i and elliptic curve points G.sub.i; send the m.sub.1 elliptic curve points P.sub.i to the secure processor.

Described are various embodiments of a cryptographic process for portable devices, and user presence and/or access authorization systems and methods employing such protocols. In one embodiment, a digital user authentication system is described to comprise a wireless digital user authentication device (UAD) operable to authenticate the user and wirelessly communicate an authenticated identity thereof; and a network application operatively associated with a wireless access point and operable to authenticate the user presence. Upon the network application authenticating the user presence based, at least in part, on the authenticated identity, the UAD and the network application securely establish a short-term symmetric advertising (STSA) key. During a prescribed advertising lifetime of the STSA, the UAD periodically computes and advertises authentication codes encompassing the STSA key so to securely advertise the authenticated user presence.

The invention relates to distributed ledger technologies such as consensus-based blockchains. Computer-implemented methods for parameterized smart contracts are described. The invention is implemented using a blockchain network, which may be, for example, a Bitcoin blockchain. A first transaction is received at a node in a blockchain network to validate, with the first transaction including a first script that, as a result of being executed, causes the node to at least obtain data and a first set of field values of the first transaction. A second transaction is obtained, with the second transaction including a second script that, as a result of being executed, causes the node to at least determine, based at least in part on the data supplied as a result of execution of the first script, a set of constraints, and verify, based at least in part on the first set of field values, that the set of constraints are applicable to the first transaction. The first transaction is validated according to the set of constraints as a result of execution of the first script and the second script.

A method for misbehaviour warnings in an intelligent transportation system (ITS) including determining at a network server that an ITS station is misbehaving. In response to determining that the ITS station is misbehaving, the network server transmits a misbehaviour warning message to the ITS station indicating that the ITS station is misbehaving. In response to transmitting the misbehaviour warning message and determining that the ITS station is continuing to misbehave, the network server includes information of the ITS station in a certificate revocation list (CRL) and transmits the CRL.

A method of communicating a secret (k.sub.0, k.sub.1) on the Bitcoin blockchain is disclosed. The method comprises sending information identifying secrets selectable by the recipient and receiving a first public key (U.sub.i) of an elliptic curve cryptography system, corresponding to a first secret (S.sub.i) selected for access by the recipient and for which a first private key (m) is accessible to the recipient. A second public key (U.sub.1-i) is received, corresponding to a second secret not selected for access by the recipient, wherein a corresponding second private key is not available to the recipient. First and second secrets encrypted by means of the respective first and second public keys (X.sub.0, X.sub.1) are sent to the recipient, wherein the first secret is accessible to the recipient by means of the first private key, the second secret is inaccessible to the recipient, and the sender is unable to distinguish between the first and second secrets.

At least one computer processor configured with a single prime field accelerator having software-based instructions operably configured to compute both isogeny-based cryptography equations and elliptic curve cryptography equations using a plurality of shared computations resident on a shared memory storage and that include finite field arithmetic and elliptic curve group arithmetic sequentially computed with an architecture controller.