Cosign Verify fails with azure akv intermittent

[suryabaiarava]

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Hi Team,

We're encountering intermittent errors while using cosign verify in our container CICD pipelines. Where cosign verify fails, we receive the following error message:

main.go:69: error during command execution: no matching signatures: failed with vault verification.

Despite the error, we've noticed that the image digest value (SHA) remains unmodified, and the corresponding .sig file exists.

As a temporary workaround, resigning the image resolves the issue. However, we'd like to troubleshoot and resolve the underlying cause.

Cosign Version: v2.2.3 CLI Syntax: cosign verify --key azurekms:///keyname acrimage/repo:sha256:fdkkdkfdkfd

Could anyone provide guidance on how to troubleshoot this issue effectively?

Any assistance would be greatly appreciated.

Thank you!