verifiable_public_key_fetcher.go

package bertyvcissuer

import (
	"crypto/ed25519"
	"fmt"
	"strings"

	"github.com/hyperledger/aries-framework-go/pkg/doc/signature/verifier"
	"github.com/hyperledger/aries-framework-go/pkg/kms"
	"github.com/multiformats/go-multibase"

	"berty.tech/berty/v2/go/pkg/errcode"
)

func embeddedPublicKeyFetcher(issuerID string) (*verifier.PublicKey, error) {
	_, rawData, err := multibase.Decode(issuerID[8:])
	if err != nil {
		return nil, err
	}

	if len(rawData) != ed25519.PublicKeySize+2 {
		return nil, errcode.ErrInvalidInput
	}

	return &verifier.PublicKey{
		Type:  kms.ED25519,
		Value: rawData[2:],
		JWK:   nil,
	}, nil
}

func EmbeddedPublicKeyFetcher(issuerID, keyID string) (*verifier.PublicKey, error) {
	if !strings.HasPrefix(issuerID, "did:key:z6Mk") {
		return nil, fmt.Errorf("unexpected key format")
	}

	return embeddedPublicKeyFetcher(issuerID)
}

func EmbeddedPublicKeyFetcherAllowList(allowList []string) func(issuerID, keyID string) (*verifier.PublicKey, error) {
	return func(issuerID, keyID string) (*verifier.PublicKey, error) {
		if !strings.HasPrefix(issuerID, "did:key:z6Mk") {
			return nil, fmt.Errorf("unexpected key format")
		}

		return embeddedPublicKeyFetcher(issuerID)
	}
}