IP Library Granted Patent US 12,452,037
Granted Patent B2
US 12,452,037 · App. 18/406,314 · Granted Oct 21, 2025

Generating private keys for quantum-safe algorithms on constrained devices

Inventor: Avesta Hojjati (Austin, TX)
Assignee: DigiCert, Inc.
H04L9/0825H04L9/0852
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Quick Facts
Patent No.
US 12,452,037
App. No.
18/406,314
Granted
Oct 21, 2025
Kind
B2
Abstract

A constrained device includes a processor; and memory storing program code that is configured to cause the processor to, responsive to a requirement for a private key for a function, perform operations on a plurality of seeds to obtain the private key; store the private key in the memory; and utilize the private key for the function. The program code is further configured to cause the processor to, subsequent to the function, remove the private key from the memory. The private key is for a quantum-safe algorithm. Advantageously, the present disclosure supports longer private keys for the quantum-safe algorithm, relative to existing algorithms, with limited resources in the constrained device.

Claims (36)

1. A constrained device comprising:

a processor; and

memory storing program code that is configured to cause the processor to:

responsive to a requirement for a private key for a function, perform operations on a plurality of seeds to obtain the private key;

store the private key in the memory; and

utilize the private key for the function,

wherein the program code is further configured to, for upgrading the constrained device from using non-quantum safe algorithm to a quantum safe algorithm, cause the processor to:

delete an existing private key stored in the memory, wherein the existing private key is for a non-quantum safe algorithm; and

receive and store the plurality of seeds and associated program code for the operations on the plurality of seeds to obtain the private key.

2. The constrained device of claim 1 , wherein the program code is further configured to cause the processor to:

subsequent to the function, remove the private key from the memory.

3. The constrained device of claim 1 , wherein the private key is for a quantum-safe algorithm.

4. The constrained device of claim 3 , wherein the quantum-safe algorithm is one of lattice-based, hash-based, code-based, multivariate-based, and isogeny-based.

5. The constrained device of claim 1 , wherein the program code is further configured to cause the processor to:

prior to the requirement for the private key, store the plurality of seeds in the memory.

6. The constrained device of claim 1 , wherein the memory further stores the plurality of seeds and logic that defines the operations on the plurality of seeds to obtain the private key.

7. The constrained device of claim 1 , wherein the function relates to one of authentication, encrypted communication, enrollment, provisioning, and upgrades.

8. The constrained device of claim 1 , wherein the constrained device is an Internet-of-Things (IoT) device.

9. The constrained device of claim 1 , wherein the constrained device is a battery-powered tracker tag.

10. A method implemented by a constrained device, the method comprising steps of:

responsive to a requirement for a private key for a function associated with the constrained device, performing operations on a plurality of seeds to obtain the private key;

storing the private key in memory of the constrained device; and

utilizing the private key for the function,

wherein the constrained device utilizes a non-quantum safe algorithm with an existing private key stored in memory, and, for upgrading the constrained device from using the non-quantum safe algorithm to a quantum safe algorithm, the steps further include:

deleting the existing private key stored in the memory; and

receiving and storing the plurality of seeds and associated program code for the operations on the plurality of seeds to obtain the private key.

11. The method of claim 10 , wherein the steps further include:

subsequent to the function, removing the private key from the memory.

12. The method of claim 10 , wherein the private key is for a quantum-safe algorithm.

13. The method of claim 12 , wherein the quantum-safe algorithm is one of lattice-based, hash-based, code-based, multivariate-based, and isogeny-based.

14. The method of claim 10 , wherein the steps further include:

prior to the requirement for the private key, storing the plurality of seeds in the memory.

15. The method of claim 10 , wherein the memory stores the plurality of seeds and logic that defines the operations on the plurality of seeds to obtain the private key.

16. The method of claim 10 , wherein the function relates to one of authentication, encrypted communication, enrollment, provisioning, and upgrades.

17. The method of claim 10 , wherein the constrained device is an Internet-of-Things (IoT) device.

18. The method of claim 10 , wherein the constrained device is a battery-powered tracker tag.

Assignments (3)
FIRST LIEN INTELLECTUAL PROPERTY AGREEMENT SUPPLEMENT Recorded Sep 24, 2025
From: DIGICERT, INC.
To: HPS INVESTMENT PARTNERS, LLC, AS COLLATERAL AGENT
Reel/Frame 072947/0203 →
SECOND LIEN INTELLECTUAL PROPERTY SECURITY AGREEMENT SUPPLEMENT Recorded Jul 30, 2025
From: DIGICERT, INC.
To: UBS AG, STAMFORD BRANCH, AS COLLATERAL AGENT
Reel/Frame 072295/0001 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 8, 2024
From: HOJJATI, AVESTA
To: DIGICERT, INC.
Reel/Frame 066046/0457 →
Continuity (1)
Related Publication 20250226973A1 · Jul 10, 2025
References Cited (8)
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