ed25519_utils.go raw

   1  package jwt
   2  
   3  import (
   4  	"crypto"
   5  	"crypto/ed25519"
   6  	"crypto/x509"
   7  	"encoding/pem"
   8  	"errors"
   9  )
  10  
  11  var (
  12  	ErrNotEdPrivateKey = errors.New("key is not a valid Ed25519 private key")
  13  	ErrNotEdPublicKey  = errors.New("key is not a valid Ed25519 public key")
  14  )
  15  
  16  // ParseEdPrivateKeyFromPEM parses a PEM-encoded Edwards curve private key
  17  func ParseEdPrivateKeyFromPEM(key []byte) (crypto.PrivateKey, error) {
  18  	var err error
  19  
  20  	// Parse PEM block
  21  	var block *pem.Block
  22  	if block, _ = pem.Decode(key); block == nil {
  23  		return nil, ErrKeyMustBePEMEncoded
  24  	}
  25  
  26  	// Parse the key
  27  	var parsedKey any
  28  	if parsedKey, err = x509.ParsePKCS8PrivateKey(block.Bytes); err != nil {
  29  		return nil, err
  30  	}
  31  
  32  	var pkey ed25519.PrivateKey
  33  	var ok bool
  34  	if pkey, ok = parsedKey.(ed25519.PrivateKey); !ok {
  35  		return nil, ErrNotEdPrivateKey
  36  	}
  37  
  38  	return pkey, nil
  39  }
  40  
  41  // ParseEdPublicKeyFromPEM parses a PEM-encoded Edwards curve public key
  42  func ParseEdPublicKeyFromPEM(key []byte) (crypto.PublicKey, error) {
  43  	var err error
  44  
  45  	// Parse PEM block
  46  	var block *pem.Block
  47  	if block, _ = pem.Decode(key); block == nil {
  48  		return nil, ErrKeyMustBePEMEncoded
  49  	}
  50  
  51  	// Parse the key
  52  	var parsedKey any
  53  	if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
  54  		return nil, err
  55  	}
  56  
  57  	var pkey ed25519.PublicKey
  58  	var ok bool
  59  	if pkey, ok = parsedKey.(ed25519.PublicKey); !ok {
  60  		return nil, ErrNotEdPublicKey
  61  	}
  62  
  63  	return pkey, nil
  64  }
  65