ConnectBot SSH Library/org.connectbot.sshlib/AuthHandler/onSignatureRequest

onSignatureRequest

abstract suspend fun onSignatureRequest(key: AuthPublicKey, dataToSign: ByteArray): ByteArray?(source)

Called only for keys the server accepted (PK_OK). Return the signature over dataToSign, or null to skip this key.

The returned bytes are written verbatim into the publickey SSH_MSG_USERAUTH_REQUEST signature field — the library does not decode or repackage them. This makes the callback a clean extension point for externally-signed keys.

Use cases:

Local private key: call SshSigning.sign.
SSH agent: forward dataToSign to your agent and return its response.
FIDO2 / Security Key (sk-ssh-ed25519@openssh.com, sk-ecdsa-sha2-nistp256@openssh.com): drive your CTAP2 stack with clientDataHash = SHA-256(dataToSign), then return org.connectbot.sshlib.sk.SkSignatureBlob.pack(algorithm, rawSignature, flags, counter). See org.connectbot.sshlib.sk.SkAuthHelpers for the matching public-key blob constructor.