agent

type AddedKey struct {
	// PrivateKey must be a *rsa.PrivateKey, *dsa.PrivateKey,
	// ed25519.PrivateKey or *ecdsa.PrivateKey, which will be inserted into the
	// agent.
	PrivateKey interface{}
	// Certificate, if not nil, is communicated to the agent and will be
	// stored with the key.
	Certificate *ssh.Certificate
	// Comment is an optional, free-form string.
	Comment string
	// LifetimeSecs, if not zero, is the number of seconds that the
	// agent will store the key for.
	LifetimeSecs uint32
	// ConfirmBeforeUse, if true, requests that the agent confirm with the
	// user before each use of this key.
	ConfirmBeforeUse bool
	// ConstraintExtensions are the experimental or private-use constraints
	// defined by users.
	ConstraintExtensions []ConstraintExtension
}

type Agent interface {
	// List returns the identities known to the agent.
	List() ([]*Key, error)

	// Sign has the agent sign the data using a protocol 2 key as defined
	// in [PROTOCOL.agent] section 2.6.2.
	Sign(key ssh.PublicKey, data []byte) (*ssh.Signature, error)

	// Add adds a private key to the agent.
	Add(key AddedKey) error

	// Remove removes all identities with the given public key.
	Remove(key ssh.PublicKey) error

	// RemoveAll removes all identities.
	RemoveAll() error

	// Lock locks the agent. Sign and Remove will fail, and List will empty an empty list.
	Lock(passphrase []byte) error

	// Unlock undoes the effect of Lock
	Unlock(passphrase []byte) error

	// Signers returns signers for all the known keys.
	Signers() ([]ssh.Signer, error)
}

type ConstraintExtension struct {
	// ExtensionName consist of a UTF-8 string suffixed by the
	// implementation domain following the naming scheme defined
	// in Section 4.2 of RFC 4251, e.g.  "foo@example.com".
	ExtensionName string
	// ExtensionDetails contains the actual content of the extended
	// constraint.
	ExtensionDetails []byte
}

type ExtendedAgent interface {
	Agent

	// SignWithFlags signs like Sign, but allows for additional flags to be sent/received
	SignWithFlags(key ssh.PublicKey, data []byte, flags SignatureFlags) (*ssh.Signature, error)

	// Extension processes a custom extension request. Standard-compliant agents are not
	// required to support any extensions, but this method allows agents to implement
	// vendor-specific methods or add experimental features. See [PROTOCOL.agent] section 4.7.
	// If agent extensions are unsupported entirely this method MUST return an
	// ErrExtensionUnsupported error. Similarly, if just the specific extensionType in
	// the request is unsupported by the agent then ErrExtensionUnsupported MUST be
	// returned.
	//
	// In the case of success, since [PROTOCOL.agent] section 4.7 specifies that the contents
	// of the response are unspecified (including the type of the message), the complete
	// response will be returned as a []byte slice, including the "type" byte of the message.
	Extension(extensionType string, contents []byte) ([]byte, error)
}

type Key struct {
	Format  string
	Blob    []byte
	Comment string
}

type SignatureFlags uint32