hyperledger/fabric · critical

could not serialize the signing identity

Error message

could not serialize the signing identity

What it means

In Fabric's default endorsement plugin, after the signing identity for the proposal is fetched, it must be serialized into bytes (the endorser's certificate chain) to be embedded in the endorsement. This error wraps the failure of signer.Serialize(), meaning the local MSP membership provider could not produce a serialized identity for this peer's signer.

Source

Thrown at core/handlers/endorsement/builtin/default_endorsement.go:43

// 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, errors.Wrap(err, "failed fetching signing identity")
	}
	// serialize the signing identity
	identityBytes, err := signer.Serialize()
	if err != nil {
		return nil, nil, errors.Wrapf(err, "could not serialize the signing identity")
	}

	// 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, errors.Wrapf(err, "could not sign the proposal response payload")
	}
	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. Verify the peer's local MSP directory (core.yaml: peer.mspConfigPath) contains valid signcerts, keystore, and cacerts and restart the peer
2. Regenerate the crypto material for this peer's organization and redeploy the peer
3. Check crypto library configuration (BCCSP: SW vs PKCS#11) matches the keystore format actually on disk
4. Inspect the wrapped inner error in the peer log for the underlying serialization cause

Example fix

// before: peer launched with stale MSP after cert rotation
//   ERROR ... could not serialize the signing identity: pem import failed
// after: point peer at regenerated MSP and restart
// core.yaml
peer:
  mspConfigPath: /var/hyperledger/msp/signcerts-regenerated
// then: docker restart peer0.org1.example.com

signer, err := fetcher.SigningIdentityForRequest(sp)
if err != nil { return err }
if _, err := signer.Serialize(); err != nil {
    return fmt.Errorf("peer signing identity not serializable: %w", err)
}

func isSerializable(signer msp.SigningIdentity) bool {
    _, err := signer.Serialize()
    return err == nil
}

When it happens

Trigger: Calling Endorse on the builtin default endorsement plugin (DefaultEndorsement.Endorse) when signer.Serialize() fails — typically because the peer's local MSP identity material is missing, malformed, or the crypto material cannot be marshaled into the MSProtobuf identity form.

Common situations: Peer started with a corrupted or incomplete mspConfigPath/adminCerts configuration; crypto material regenerated by 'cryptogen' or an HSM after the peer cached it; expired or mismatched certificates in the local MSP folder; hardware security module (PKCS#11) keystore errors during identity export.

Related errors

• could not serialize the signing identity: %v
• implicit policy evaluation failed - %d sub-policies were sat
• error converting policy with reference '%s' on channel '%s'
• collection-name: %s -- collection member '%s' is not part of
• collection-name: %s -- contains an identity that is not part

AI-assisted analysis of hyperledger/fabric@2736b63f8f (2026-09-04). Data as JSON: /api/errors/53f9854a608f06c1. Report an issue: GitHub.