hyperledger/fabric · critical

could not serialize the signing identity: %v

Error message

could not serialize the signing identity: %v

What it means

In the pluggable endorsement DefaultEndorsement.Endorse, signer.Serialize() converts the resolved signing identity into bytes for the Endorser field of the peer.Endorsement. This error indicates the identity exists but its serialized form could not be produced by the MSP/crypto layer.

Source

Thrown at core/handlers/endorsement/plugin/plugin.go:49

// DefaultEndorsement is an endorsement plugin that behaves as the default endorsement system chaincode
type DefaultEndorsement struct {
	identities.SigningIdentityFetcher
}

// Endorse signs the given payload(ProposalResponsePayload bytes), and optionally mutates it.
// Returns:
// The Endorsement: A signature over the payload, and an identity that is used to verify the signature
// The payload that was given as input (could be modified within this function)
// Or error on failure
func (e *DefaultEndorsement) Endorse(prpBytes []byte, sp *peer.SignedProposal) (*peer.Endorsement, []byte, error) {
	signer, err := e.SigningIdentityForRequest(sp)
	if err != nil {
		return nil, nil, fmt.Errorf("failed fetching signing identity: %v", err)
	}
	// serialize the signing identity
	identityBytes, err := signer.Serialize()
	if err != nil {
		return nil, nil, fmt.Errorf("could not serialize the signing identity: %v", err)
	}

	// sign the concatenation of the proposal response and the serialized endorser identity with this endorser's key
	signature, err := signer.Sign(append(prpBytes, identityBytes...))
	if err != nil {
		return nil, nil, fmt.Errorf("could not sign the proposal response payload: %v", err)
	}
	endorsement := &peer.Endorsement{Signature: signature, Endorser: identityBytes}
	return endorsement, prpBytes, nil
}

// Init injects dependencies into the instance of the Plugin
func (e *DefaultEndorsement) Init(dependencies ...endorsement.Dependency) error {
	for _, dep := range dependencies {
		sIDFetcher, isSigningIdentityFetcher := dep.(identities.SigningIdentityFetcher)
		if !isSigningIdentityFetcher {
			continue
		}

View on GitHub (pinned to 2736b63f8f)

Solutions

1. Inspect the wrapped serialization error from the peer/plugin log
2. Validate the local MSP tree (signcerts, keystore, cacerts, admincerts) is complete and well-formed PEM
3. Re-import or regenerate the peer's MSP material and recreate the plugin instance
4. When using an HSM, confirm the token allows the operations the crypto library needs

Example fix

// before: signcerts contains an empty/corrupt PEM
//   could not serialize the signing identity: ... asn1: structure error
// after: replace with a valid signer cert
// cp valid-cert.pem /var/hyperledger/msp/signcerts/cert.pem
// restart peer / recreate plugin with fresh SigningIdentityFetcher

signer, err := fetcher.SigningIdentityForRequest(sp)
if err != nil { return err }
if _, err := signer.Serialize(); err != nil {
    return fmt.Errorf("cannot serialize signing identity, check MSP material: %w", err)
}

func canSerialize(id msp.SigningIdentity) bool {
    b, err := id.Serialize()
    return err == nil && len(b) > 0
}

When it happens

Trigger: Endorse (invoked via EndorseWithPlugin or TestEndorsementPlugin) successfully fetched the signer but signer.Serialize() fails — corrupt/missing local MSP cert chain, BCCSP keystore problems, or an identity whose certificate bytes cannot be marshaled to the identity protobuf.

Common situations: Partial crypto material on disk (signcerts present but malformed); PKCS#11 HSM export restrictions; identity certificates regenerated under the peer while an old signer handle is cached in tests.

Related errors

• could not serialize the signing identity
• failed fetching signing identity: %v
• could not sign the proposal response payload: %v
• Unknown hashing algorithm type: %s
• error converting policy with reference '%s' on channel '%s'

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/b22c771bb0bb4984. Report an issue: GitHub.