Visa International Service Association

Yilei Chen

Pratyay Mukherjee

Daniel Masny

Gaven James Watson

Rouzbeh Behnia

Binyi Chen

Mihai Christodorescu

Shashank Agrawal

Minghua Xu

Vinjith Nagaraja

Jose Rios Trevino

Nicholas Genise

Estuardo Alpirez Bock

Embodiments are directed to methods and systems for crypto-agile encryption and decryption. A computer system can possess a protocol file that identifies one or more cryptographic software modules. Using these cryptographic software modules, the computer system can generate a plurality of shared secrets and a session key, then use the session key to encrypt a message. The message can be sent to a server computer that can subsequently decrypt the message. At a later time, the protocol file can be updated to identify a different set of cryptographic software modules, which can be used to encrypt messages. Further, the server computer can transmit additional cryptographic software modules to the computer system, enabling the computer system to use those cryptographic software modules to generate cryptographic keys. As such, the cryptographic protocol file can be changed in response to changes in the cryptographic needs of the computer system.

Agile cryptographic deployment service

A method is disclosed. The method includes receiving, by a user device, an encrypted message from a server computer. The encrypted message is a message encrypted with a master secret key or a key derived from the master secret key. The user device signs the encrypted message with a secure element private key. The user device, using a whitebox, cryptographically recovers a secure element public key from a certified key using a server computer public key. The certified key is certified by the server computer and based on at least the secure element public key. The user device, using the whitebox, cryptographically recovers the encrypted message from the signed encrypted message using the secure element public key. The user device, using the whitebox, decrypts the encrypted message using the master secret key or the key derived from the master secret key in the whitebox to obtain the message.

Systems and methods for whitebox device binding

Improvements to post-quantum lattice-based digital signature schemes are disclosed. By sampling cryptographic material, including cryptographic key matrices and masking vectors from a uniform distribution, embodiments eliminate the need for a security check during generation of a digital signature vector. As a result, digital signatures can be generated faster and at a lower failure rate. A generating device can generate a verification matrix A and a secret matrix S from a uniform distribution, and an error matrix E from a special distribution (such as a Gaussian). The generating device can combine the three matrices to generate a public matrix Y. The first and the fourth matrices (A, Y) can be used as a public key used to verify digital signatures. The second and the third matrices (S, E) can be used as a private key used to generate digital signatures.

Lattice based signatures with uniform secrets

Systems, methods, and apparatuses for protecting a secret on a device with limited memory, while still providing tamper resistance, are described. To achieve security, an encoding computer can apply a memory-hard function MHF to a secret S and determine a result Y, then determine a proof π for the result Y. Then, the encoding computer can send a codeword C comprising the secret S and the proof π to a decoding computer. The decoding computer can retrieve the codeword C from persistent memory and parse the secret S and the proof π. The decoding device can use transient memory to decode the codeword C by verifying the proof π was generated with the secret S and the result Y. When the correctness of the result Y is verified, the decoding device can apply a cryptographic function to input data using the secret S then reset the transient memory.

Continuous space-bounded non-malleable codes from stronger proofs-of-space

Techniques of generating a lattice-based verification matrix and signature vector are disclosed. The method enables a generating device to sample a gadget matrix and then generate a reduced gadget matrix. The generating device may then sample a trapdoor matrix and use the trapdoor matrix and the reduced gadget matrix to generate a verification matrix. A sending device may receive the trapdoor matrix and the verification matrix from the generating device, in addition to receiving a message. The sending device may then use the trapdoor matrix and the verification matrix to generate a signature vector for the message. A verification device can receive the verification matrix, the message, and the signature vector. The verification device may use the verification matrix and the signature vector to verify the message.

Growing community of inventors

Palo Alto, CA, United States of America

Yilei Chen