Files
did-it/did-key/key.go
2025-03-13 11:26:39 +01:00

92 lines
1.9 KiB
Go

package did_key
import (
"fmt"
"net/url"
"strings"
mbase "github.com/multiformats/go-multibase"
"github.com/multiformats/go-varint"
"github.com/INFURA/go-did"
"github.com/INFURA/go-did/verifications/ed25519"
)
// Specification: https://w3c-ccg.github.io/did-method-key/
func Decode(identifier string) (did.DID, error) {
const keyPrefix = "did:key:"
if !strings.HasPrefix(identifier, keyPrefix) {
return nil, fmt.Errorf("must start with 'did:key'")
}
baseCodec, bytes, err := mbase.Decode(identifier[len(keyPrefix):])
if err != nil {
return nil, fmt.Errorf("%w: %w", did.ErrInvalidDid, err)
}
// the specification enforces that encoding
if baseCodec != mbase.Base58BTC {
return nil, fmt.Errorf("%w: not Base58BTC encoded", did.ErrInvalidDid)
}
code, read, err := varint.FromUvarint(bytes)
if err != nil {
return nil, fmt.Errorf("%w: %w", did.ErrInvalidDid, err)
}
d := DidKey{identifier: identifier}
switch code {
case ed25519.MultibaseCode:
d.verification, err = ed25519.NewVerificationKey2020(identifier, bytes[read:], d)
// case P256: // TODO
// case Secp256k1: // TODO
// case RSA: // TODO
default:
return nil, fmt.Errorf("%w: unsupported did:key multicodec: 0x%x", did.ErrInvalidDid, code)
}
if err != nil {
return nil, fmt.Errorf("%w: %w", did.ErrInvalidDid, err)
}
return d, nil
}
func init() {
did.RegisterMethod("key", Decode)
}
var _ did.DID = &DidKey{}
type DidKey struct {
identifier string // cached value
verification did.VerificationMethod
}
func (d DidKey) Method() string {
return "key"
}
func (d DidKey) Path() string {
return ""
}
func (d DidKey) Query() url.Values {
return nil
}
func (d DidKey) Fragment() string {
return ""
}
func (d DidKey) Document() (did.Document, error) {
return document{
id: d,
verification: d.verification,
}, nil
}
func (d DidKey) String() string {
return d.identifier
}