	US 12,261,935 B2
	Protecting polynomial hash functions from external monitoring attacks
Elena Trichina, Aix-en-Provence (FR); Guilherme Ozari de Almeida, Nootdorp (NL); and Elke De Mulder, Kirkland, WA (US)
Assigned to Cryptography Research, Inc., San Jose, CA (US)
Filed by Cryptography Research, Inc., San Jose, CA (US)
Filed on Nov. 25, 2020, as Appl. No. 17/105,247.
Application 17/105,247 is a continuation of application No. 15/646,614, filed on Jul. 11, 2017, granted, now 10,855,443.
Claims priority of provisional application 62/437,387, filed on Dec. 21, 2016.
Claims priority of provisional application 62/368,900, filed on Jul. 29, 2016.
Prior Publication US 2021/0152331 A1, May 20, 2021
This patent is subject to a terminal disclaimer.
Int. Cl. H04L 9/06 (2006.01); G09C 1/00 (2006.01); H04L 9/32 (2006.01)

CPC H04L 9/0631 (2013.01) [G09C 1/00 (2013.01); H04L 9/0637 (2013.01); H04L 9/0643 (2013.01); H04L 9/3236 (2013.01); H04L 2209/046 (2013.01); H04L 2209/12 (2013.01)]

20 Claims

1. A method for performing a cryptographic operation, the method comprising:

receiving, by a processing device, an input data block and an unmasked result value;

multiplying a mask value by a combination of the input data block and the unmasked result value to produce a mask correction value;

multiplying a masked hash key by the combination of the input data block and the unmasked result value to produce a masked result value;

determining a new unmasked result value by applying the mask correction value to the masked result value; and

protecting the cryptographic operation from external monitoring attacks by utilizing the new unmasked result value as a value of a polynomial hash function in the cryptographic operation.