Sign certificates with an external CA signer - #59
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SshCertificateBuilder.SignWith signed with the CA key's embedded private material, so a CA whose private key lives outside the process — in a TPM or HSM — could not sign a certificate: the public-only Key has no private part. Add SignWith(KeyHostAlgorithm), which signs through the algorithm's own signer and never needs the private key; SignWith(Key) delegates to it, so existing behaviour is unchanged. Bump to 2024.2.0.5.
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Why
SshCertificateBuilder.SignWithsigns with the CA key's embedded private material — it rebuilds a signature from theKey. So a CA whose private key lives outside the process (a TPM or HSM) cannot sign a certificate: the exported public-onlyKeyhas no private part, and signing throwsmissing private key.Changes
SignWith(KeyHostAlgorithm caAlgorithm)— new overload that signs through the algorithm's own signer, so the CA key is never exported. Pass, for example, the first entry of anIPrivateKeySource.HostKeyAlgorithmsbacked by a TPM/HSM signer.Sign(KeyHostAlgorithm);SignWith(Key)now delegates to it viaCaHostAlgorithm(caKey), so existing behaviour (including an RSA CA signing withrsa-sha2-512) is unchanged.SignWithHostAlgorithmSelfVerifiesover RSA/ECDSA/ED25519 CAs, driving the external-signer path.Testing
Full certificate suite (28 tests) passes on net48 and net8.0, including the
ssh-keygen -Linterop cases.Version
2024.2.0.4 → 2024.2.0.5.