Hewlett-Packard Development Company, L.p.

Thalia Laing

Joshua Serratelli Schiffman

Stephen D Panshin

Laurent Pizot

Gaetan Wattiau

Boris Balacheff

Adrian John Baldwin

Maugan Villatel

Shivaun Albright

Gurchetan Grewal

Pierre Louis Robert Belgarric

Ilja Siros

In an example, a computing device is described. The computing device comprises a memory to store a set of states and a corresponding set of non-overlapping time intervals. The computing device further comprises a timing unit to indicate a time at which a signature is to be produced. The computing device further comprises a processor to: identify which time interval of the set of non-overlapping time intervals includes the indicated time; generate a signing key based on a state associated with the identified time interval; and produce a signature, under a stateful signature scheme, with the signing key.

Time intervals for stateful signature production

A public key service determines a seed value used by a sending device to generate a one-time signature (OTS) private key that the sending device uses to digitally sign a message before sending the message to a receiving device. The public key service generates, based on the seed value, a public key used to authenticate the digitally signed message as having been sent by the sending device. The public key service receives a request for the public key from the receiving device, and in response sends the public key to the receiving device, such that the receiving device is able to authenticate the message.

Public key service for message authentication

A block to be added to a hash chain is generated. The block is for a message to be sent and includes a link hash of a prior block previously added to the hash chain. The prior block includes a public key corresponding to a private key to be used to digitally sign the block. The block includes a payload hash of a payload of the message, and a next public key corresponding to a next private key to be used to digitally sign a next block to be added to the hash chain after the block. The next block is for a next message to be sent after the message. The block is digitally signed with the private key and added to the hash chain. The link hash links the block to the prior block in the hash chain. The message is sent.

Hash chain of blocks of public keys for messages

Examples relate to machine readable storage storing instructions arranged, when processed, to realise methods of verifying as valid a received signature, associated with a respective received message, generated using a Merkle Signature Scheme comprising a Merkle Tree, the Merkel Tree comprising a root node, a number of leaf nodes and a number of intermediate nodes disposed between the root node and the leaf nodes; the instructions comprising instructions to:

Signature verifications using Merkle signature schemes

A system, comprising an authentication module to generate a challenge to authenticate a user, the challenge to be distributed to members of a set of verifying parties; and grant the user access to a resource upon receiving an authenticating response to the challenge; and a combiner module to receive partial responses from members of the set of verifying parties upon verification of the user by each member, the verification made using a provided contextual identifier of the user; based on the partial responses reaching a threshold number of responses, combine the partial responses to obtain a combined response, and provide the combined response to the authentication module as an authenticating response to the challenge.

Contextual authorisation

According to aspect of the present disclosure there are provided methods and apparatus for printing to a group of printers in a network, including a method comprising provisioning each printing device of the plurality of printing devices with a respective private cryptographic key, defining a first group of printing devices comprising a first subset of the plurality of printing devices, generating a first group public key for the defined first group of printing devices, the first group public key generated based on public cryptographic keys corresponding to the respective private cryptographic keys provisioned to the first subset of the plurality of printing devices, and providing the first group public key to a user.

Group printing

In an example, a method of encryption is described to include generation of a content encryption key and a key encryption key. In that example, the content encryption key is wrapped based on a key wrap operation using the key encryption key and the wrapped content encryption key is encrypted using a policy encryption key. Further in that example, the policy encryption key is encrypted using a public key corresponding to a print apparatus. In an example, a method of decryption is described. The example method of decryption performs recovery of a policy object using a private key corresponding to a print apparatus. In that example, the policy object includes a wrapped key that is unwrapped using a key encryption key to recover a content encryption key usable to decrypt an encrypted electronic document.

Key encryption key wrapping

A network printing system comprising a user device to encrypt a print job using a public key of a user and to transmit the encrypted print job to a print server. The system may further comprise the print server to re-encrypt the encrypted print job using the re-encryption key. The system may further comprise the printer to decrypt the re-encrypted print job using a private key of the printer and print the decrypted print job.

Public key encrypted network printing

Examples associated with distributed authentication are described. One example includes generating a paired public key and private key associated with a user. The private key is split into a set of shares, which are distributed to a set of devices associated with the user. A challenge is generated to authenticate the user to grant the user access to a resource upon receiving an authenticating response to the challenge. The challenge is distributed to members of the set of devices. Partial responses are received from members of the set of devices and combined into a group signature. The group signature serves as an authenticating response to the challenge when generated from partial responses received from a threshold number of members of the set of devices.

Growing community of inventors

Bristol, United Kingdom

Thalia Laing