signer

type Algorithm interface {
	Type() string
	Sign(ctx context.Context, base string) ([]byte, error)
	// ContentDigest specifies the HTTP body digest algorithm
	// to use when covering the 'content-digest' component
	// on an HTTP request.
	ContentDigest() contentdigest.Digester
}

type Labeler interface {
	Label(existingCount int) string
}

type Transport struct {
	// KeyID is the identifier for the key to use for signing requests.
	KeyID string

	// Tag is an application-specific tag for the signature as a String value.
	// This value is used by applications to help identify signatures relevant for specific applications or protocols.
	// See: https://www.rfc-editor.org/rfc/rfc9421.html#section-2.3-4.12
	Tag string

	// Alg is the signing algorithm to use.
	Alg Algorithm

	// CoveredComponents specify the components of the request
	// to be covered with the signature.
	//
	// An ordered set of HTTP message component identifiers for fields (Section 2.1)
	// and derived components (Section 2.2) that indicates the set of message components
	// covered by the signature, never including the @signature-params identifier itself.
	// The order of this set is preserved and communicated between the signer and verifier
	// to facilitate reconstruction of the signature base.
	//
	// See: https://www.rfc-editor.org/rfc/rfc9421.html#section-1.1-7.18.1
	CoveredComponents []string

	// GetNonce can optionally be provided to override the built-in
	// nonce generation function. If the provided Nonce function
	// returns an empty string, a nonce will not be included
	// in the signed request.
	//
	// If Nonce is not provided, a random 32 byte string
	// will be used as the nonce.
	//
	// Including a nonce is recommended. We do not recommend
	// overriding the default behaviour here.
	//
	// See: https://www.rfc-editor.org/rfc/rfc9421.html#section-2.3-4.6
	GetNonce func() (string, error)

	// BaseTransport is the underlying HTTP transport to use
	// for sending requests after they have been signed.
	//
	// If nil, http.DefaultTransport is used.
	BaseTransport http.RoundTripper

	// OnDeriveSigningString is a hook which can be used to log
	// the string to sign.
	//
	// This can be useful for debugging signature errors,
	// as you can compare the base signing string between the client
	// and server.
	OnDeriveSigningString func(ctx context.Context, stringToSign string)
}