This disclosure relates to anonymous transactions based on ring signatures. In one aspect, a method includes receiving a remittance transaction. The remittance transaction is generated by a client device of a remitter by assembling unspent assets in an account corresponding to the remitter and masked assets in an account corresponding to a masked participant. Key images are obtained from a linkable spontaneous anonymous group (LSAG) signature of the remittance transaction. Values of the key-images are based on a private key, a public key, and unspent assets of the remitter. The LSAG signature is verified. The LSAG signature is generated by the client device of the remitter based on the private key and the public key of the remitter, and a second public key of the masked participant. The remittance transaction is executed when a transaction execution condition is met.

A projection device comprises a light source, a first attenuator and a second attenuator, a first driver, a second driver, a light receiving element, and a controller. The light source emits light. The first attenuator and the second attenuator attenuate intensity of the light from the light source. The first driver drives the first attenuator. The second driver drives the second attenuator. The light receiving element receives the light distributed by the second attenuator. The controller controls the second driver to control the distribution ratio of the light distributed to the light receiving element by the second attenuator according to control of transmissivity of light at the first attenuator by the first driver.

A method in an elliptic curve cryptographic system, the method being executed by an electronic device and including a multiplication operation of multiplying a point of an elliptic curve by a scalar number, the point having affine coordinates belonging to a Galois field, the multiplication operation including steps of detecting the appearance of a point at infinity during intermediate calculations of the multiplication operation, and of activating an error signal if the point at infinity is detected and if the number of bits of the scalar number processed by the multiplication operation is lower than the rank of the most significant bit of an order of a base point of the cryptographic system.

A method of managing implicit certificates of an elliptical curve encryption (ECQV). The implicit certificates are stored in different nodes of the network as a function of a distributed hash table (DHT) and not with a single certification authority. The implicit certificate of the public key associated with a node is obtained by chaining elementary certification operations with a sequence of indexing nodes of the network. Chaining of elementary certification operations can reinforce authentication of network nodes.

Methods, systems, and computer-readable storage mediums are described for effecting practical use of a dual currency which is a currency that can be electronically created and stored, and further for which there is a secret key (e.g., the secret key of a public key/secret key pair as used in public key cryptography) such that: an entity that does not possess the secret key cannot, in practice, create notes of the currency; and an entity that does possess the secret key can, in practice, create notes of the currency without assistance from entities that do not possess the secret key.

The invention relates to a method for logging a service technician into an electrical device (20), comprising the following steps: production (3, 4) of a secret key (SKY) as an encrypted login password (LPW) by the electrical device (20), displaying (5) of the secret key (SKY) on a display unit (23) of the electrical device (20) as a QR code (QRC), optical sensing (6) of the QR code (QRC) by means of a mobile device (22), decryption (9) of the login password (LPW) from the secret key (SKY) of the sensed QR code (QRC) by the mobile device (22), displaying of the login password (LPW) on a screen unit (24) of the mobile device (22), entering of the login password (LPW) into the electrical device (20) by the service technician, comparison (10) of the entered login password (LPW) with the produced login password (LPW) by the electrical device (20), release of the login by the electrical device (20) if the two login passwords (LPW) match. The invention further relates to an associated apparatus. The advantage of the invention lies in the combination of the high strength of the cryptographic security with the user friendliness of the QR code and of the relatively short login password to be entered.

There may be provided a blockchain-implemented security method involving a requestor and a group of nodes, which includes generating a cryptographic key of the requestor based on a password chosen by the requestor and first quantities sent by the group of nodes (which are derived from private key shares of the group of nodes and a generator function of a digital signature scheme employing a bilinear mapping on an elliptic curve). A cryptographic signature for a requestor blockchain transaction can be generated where the signature corresponds to the requestor's cryptographic key. The signature can be based on the password and second quantities sent by the group of nodes (which are also derived from the group private key shares). The method can further include verifying the cryptographic signature of the blockchain transaction using the requestor's cryptographic key. Additionally or alternatively, the method can employ a consensus mechanism involving the group of nodes to allow the requestor to authorise a transaction with a password. The method can be logically partitioned into a sequence of phases, including an initialisation phase, a funding phase, and a payment authorization phase (which involves a pre-spending transaction and a spending transaction).

Systems, methods, circuits and computer-readable mediums for controlled secure code authentication are provided. In one aspect, a non-transitory computer-readable storage medium having instructions stored thereon which, when executed by one or more processors, cause the one or more processors to perform a method including: sending a request to a client device, the request including a challenge for a property of a particular portion from among a plurality of portions of code stored within the client device, the challenge including data indicating a particular memory address range corresponding to the particular portion of the code, receiving a response to the request from the client device, the response including information associated with the property of the code, verifying correctness of the response based on the received information, and based on verifying correctness of the response, determining that the code is an authorized code.

A method and system are provided for transferring digital assets in a digital asset network. Network users can be centrally enrolled and screened for compliance. Standardized transfer processes and unique identifiers can provide a transparent and direct transfer process. Digital assets can include sufficient information for ensuring that a value will be provided, including one or more digital signatures, such that value can be made immediately available to recipients.

Disclosed herein are methods and systems for encrypting communications using a secure element. An embodiment takes the form of a method including the steps of performing a key-exchange procedure with an endpoint via a voice-communication device to obtain a symmetric seed key for a secure voice session with the endpoint; generating first and second symmetric session keys for the secure voice session based on the obtained symmetric seed key; receiving outbound voice packets from the voice-communication device in connection with the secure voice session, each outbound voice packet including a header and an unencrypted payload; using a first symmetric encryption algorithm and the first symmetric session key, followed by a second symmetric encryption algorithm and the second symmetric session key to generate and output twice-encrypted outbound-voice-packet payloads to the voice-communication device for transmission to the endpoint in connection with the secure voice session.