zitadel-oidc/pkg/crypto/key.go
2024-07-09 15:55:50 +02:00

45 lines
1.1 KiB
Go

package crypto
import (
"crypto"
"crypto/ecdsa"
"crypto/ed25519"
"crypto/rsa"
"crypto/x509"
"encoding/pem"
"errors"
"github.com/go-jose/go-jose/v4"
)
var (
ErrPEMDecode = errors.New("PEM decode failed")
ErrUnsupportedFormat = errors.New("key is neither in PKCS#1 nor PKCS#8 format")
ErrUnsupportedPrivateKey = errors.New("unsupported key type, must be RSA, ECDSA or ED25519 private key")
)
func BytesToPrivateKey(b []byte) (crypto.PublicKey, jose.SignatureAlgorithm, error) {
block, _ := pem.Decode(b)
if block == nil {
return nil, "", ErrPEMDecode
}
privateKey, err := x509.ParsePKCS1PrivateKey(block.Bytes)
if err == nil {
return privateKey, jose.RS256, nil
}
key, err := x509.ParsePKCS8PrivateKey(block.Bytes)
if err != nil {
return nil, "", ErrUnsupportedFormat
}
switch privateKey := key.(type) {
case *rsa.PrivateKey:
return privateKey, jose.RS256, nil
case ed25519.PrivateKey:
return privateKey, jose.EdDSA, nil
case *ecdsa.PrivateKey:
return privateKey, jose.ES256, nil
default:
return nil, "", ErrUnsupportedPrivateKey
}
}