HSM Migration Using Link Certificates Without Private Key Access

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Solution Overview

Problem

Existing methods for migrating Hardware Security Modules (HSMs) face challenges as they require access to the private key, which is not readable by administrators, especially during transitions to new HSMs or different vendors, leading to security and compatibility issues.

Innovation Solution

A method involving the generation of a second certificate by the new HSM, signed by the old HSM's private key, creating a link certificate that allows seamless migration without accessing the private key, ensuring security and compatibility across different HSM systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the old HSM's private key is accessed to create a link certificate, then migration between HSMs is enabled, but the security principle of private key inaccessibility is violated

Engineering Contradiction:
ImproveHSM migration capabilityVSAvoidprivate key security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent introduces a public key as an intermediary element that enables HSM migration without accessing the private key. The old HSM's public key acts as a mediator to create a link certificate that validates the new HSM, allowing migration while maintaining private key security. This resolves the contradiction by providing a migration mechanism that does not require compromising the fundamental security principle of private key inaccessibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If a new HSM with a different vendor is used, then hardware upgrades and vendor changes are enabled, but compatibility with existing certificates is lost

Engineering Contradiction:
Improvevendor interchangeabilityVSAvoidcertificate validity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The link certificate serves as an intermediary that bridges the old and new HSMs from different vendors. It contains the old HSM's public key and signatures that validate the new HSM's identity, enabling vendor interchangeability while maintaining certificate validity. This allows organizations to upgrade hardware or change vendors without invalidating existing digital identities.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs preliminary actions by having the old HSM sign the new HSM's public key before migration is complete. This creates a pre-established trust relationship that enables seamless vendor interchangeability. The link certificate is prepared in advance with the necessary signatures, ensuring that certificate validity is maintained during and after the vendor transition.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If the private key is extracted from the HSM for migration purposes, then migration can be performed, but the HSM's self-destruct mechanism is triggered

Engineering Contradiction:
ImproveHSM replaceabilityVSAvoidprivate key loss
Core Design Contradiction:
Adaptability or versatilityVSObject-generated harmful factors

Solution Approach 1:

The public key serves as a safe intermediary that enables HSM replaceability without triggering the self-destruct mechanism. Since the public key can be freely extracted and used for creating link certificates, it provides the necessary migration capability without compromising the private key. This resolves the contradiction by offering a migration path that avoids the harmful effect of private key loss entirely.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4250636B1Method for hsm migration
Publication Date: 2025.09.03 BUNDESDRUCKEREI GMBH
  • EP4250636B1 patent drawingFigure 1
  • EP4250636B1 patent drawingFigure 2
  • EP4250636B1 patent drawingFigure 3

AI summary

The invention relates to a method for migration from a first HSM (140; 101A) to a second HSM (101B), wherein the first HSM is provided with a first asymmetric cryptographic key pair comprising a first private key (142; 142A) and a first public key (147A) and a first certificate containing the first public key (144;144A), with the following steps: - Generation of a second asymmetric cryptographic key pair with a second private key (142B) and a second public key (191B) and a second certificate (190B) containing the second public key by the second HSM, - Transfer of the second certificate (190B) containing the second public key from the second HSM to the first HSM, and - Generation of a third certificate (144B) by the first HSM by signing the second public key with the first private key, whereby certificate verification of the second certificate is possible using a certificate chain containing the first and third certificates.;