IP Library Granted Patent US 12,547,773
Granted Patent B2
US 12,547,773 · App. 18/100,780 · Granted Feb 10, 2026

Utilizing hardware tokens in conjunction with HSM for code signing

Inventor: Avesta Hojjati (Austin, TX)
Assignee: DigiCert, Inc.
G06F21/64G06F21/31G06F21/602
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Quick Facts
Patent No.
US 12,547,773
App. No.
18/100,780
Granted
Feb 10, 2026
Kind
B2
Abstract

Utilizing hardware tokens in conjunction with a Hardware Security Module (HSM) for code signing includes, subsequent to storing a private key of a developer, receiving a request to sign a digest of software from the developer; receiving an approval from the developer to enable use of the private key; and responsive to the approval, encrypting and signing the digest utilizing the private key to attest the software is from the developer. The steps can further include, responsive to failing to receive the approval, denying the request. In this manner, a cloud based HSM approach can be trusted similarly to a physical hardware token approach, as well as providing the additional security benefits of an HSM over a physical hardware token.

Claims (34)

1 . A method comprising steps of:

subsequent to storing a private key of a developer in a Hardware Security Module (HSM) hosted separately from the developer, receiving a request to sign a digest of software from the developer;

receiving, by manual actuation of a hardware token physically located with the developer, an approval from the developer to enable use of the private key, wherein the private key in the HSM is only usable subsequent to the approval, and wherein the approval comprises:

requiring a secondary nuance which is separate from the HSM and the hardware token, wherein the secondary nuance for the approval includes any of a time sensitive passcode and a push notification to a pre-enrolled application;

allowing access, based on both the hardware token and the secondary nuance, to the private key in the HSM; and

responsive to the approval, encrypting and signing the digest utilizing the private key to attest the software is from the developer.

2 . The method of claim 1 , wherein the steps further include:

responsive to failing to receive the approval, denying the request.

3 . The method of claim 1 , wherein the HSM is a physically safeguarded, hardened, and tamper-resistant computing device hosted by an entity separate from the developer.

4 . The method of claim 1 , wherein the hardware token is a Universal Serial Bus (USB) token.

5 . The method of claim 1 , wherein the hardware token provides a one-time password (OTP) for the approval.

6 . The method of claim 1 , wherein the private key is associated with a code signing certificate for the developer and from a Certificate Authority.

7 . The method of claim 1 , wherein the software includes any of software applications made available for download from websites, internal Information Technology (IT) applications, mobile applications, Extensible Markup Language (XML) files, scripts, software images, containers, drivers and utilities, and firmware.

8 . The method of claim 1 , wherein the method is implemented by a cloud system with the HSM being managed by an entity separate from the developer.

9 . A Hardware Security Module (HSM) system comprising:

one or more HSM modules, each including circuitry configured to:

subsequent to storage of a private key of a developer in an HSM which is separate from the developer, receive a request to sign a digest of software from the developer;

receive, by manual actuation of a hardware token physically located with the developer, an approval from the developer to enable use of the private key, wherein the private key in the HSM is only usable subsequent to the approval, and wherein the approval comprises:

requires a second nuance which is separate from the HSM and the hardware token, wherein the secondary nuance for the approval includes any of a time sensitive passcode and a push notification to a pre-enrolled application;

allows access, based on both the hardware token and the secondary nuance, to the private key in the HSM; and

responsive to the approval, encrypt and sign the digest utilizing the private key to attest the software is from the developer.

10 . The HSM system of claim 9 , wherein the circuitry is further configured to:

responsive to failing to receive the approval, deny the request.

11 . The HSM system of claim 9 , wherein the HSM is a physically safeguarded, hardened, and tamper-resistant computing device hosted by an entity separate from the developer.

12 . The HSM system of claim 9 , wherein the hardware token is a Universal Serial Bus (USB) token.

13 . The HSM system of claim 9 , wherein the hardware token provides a one-time password (OTP) for the approval.

14 . The HSM system of claim 9 , wherein the private key is associated with a code signing certificate for the developer and from a Certificate Authority.

15 . The HSM system of claim 9 , wherein the software includes any of software applications made available for download from websites, internal Information Technology (IT) applications, mobile applications, Extensible Markup Language (XML) files, scripts, software images, containers, drivers and utilities, and firmware.

16 . A non-transitory computer-readable medium comprising instructions that, when executed, cause one or more processors in a Hardware Security Module (HSM) to perform steps of:

subsequent to storing a private key of a developer in the HSM which is hosted separately from the developer, receiving a request to sign a digest of software from the developer;

subsequent to the request, one or more of waiting for an approval from the developer by manual actuation of a hardware token physically located with the developer, to enable use of the private key and providing a notification to the developer for the approval, wherein the private key in the HSM is only usable subsequent to the approval, and wherein the approval comprises:

requiring a secondary nuance which is separate from the HSM and the hardware token, wherein the secondary nuance for the approval includes any of a time sensitive passcode and a push notification to a pre-enrolled application;

allowing access, based on both the hardware token and the secondary nuance, to the private key in the HSM; and

subsequent to receiving the approval from the developer to enable use of the private key, encrypting and signing the digest utilizing the private key to attest the software is from the developer.

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 24, 2023
From: HOJJATI, AVESTA
To: DIGICERT, INC.
Reel/Frame 062468/0469 →