text: package jwt
  
  import (
  	"crypto/ecdsa"
  	"crypto/x509"
  	"encoding/pem"
  	"errors"
  )
  
  var (
  	ErrNotECPublicKey  = errors.New("Key is not a valid ECDSA public key")
  	ErrNotECPrivateKey = errors.New("Key is not a valid ECDSA private key")
  )
  
  // Parse PEM encoded Elliptic Curve Private Key Structure
  func ParseECPrivateKeyFromPEM(key []byte) (*ecdsa.PrivateKey, error) {
  	var err error
  
  	// Parse PEM block
  	var block *pem.Block
  	if block, _ = pem.Decode(key); block == nil {
  		return nil, ErrKeyMustBePEMEncoded
  	}
  
  	// Parse the key
  	var parsedKey interface{}
  	if parsedKey, err = x509.ParseECPrivateKey(block.Bytes); err != nil {
  		return nil, err
  	}
  
  	var pkey *ecdsa.PrivateKey
  	var ok bool
  	if pkey, ok = parsedKey.(*ecdsa.PrivateKey); !ok {
  		return nil, ErrNotECPrivateKey
  	}
  
  	return pkey, nil
  }
  
  // Parse PEM encoded PKCS1 or PKCS8 public key
  func ParseECPublicKeyFromPEM(key []byte) (*ecdsa.PublicKey, error) {
  	var err error
  
  	// Parse PEM block
  	var block *pem.Block
  	if block, _ = pem.Decode(key); block == nil {
  		return nil, ErrKeyMustBePEMEncoded
  	}
  
  	// Parse the key
  	var parsedKey interface{}
  	if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
  		if cert, err := x509.ParseCertificate(block.Bytes); err == nil {
  			parsedKey = cert.PublicKey
  		} else {
  			return nil, err
  		}
  	}
  
  	var pkey *ecdsa.PublicKey
  	var ok bool
  	if pkey, ok = parsedKey.(*ecdsa.PublicKey); !ok {
  		return nil, ErrNotECPublicKey
  	}
  
  	return pkey, nil
  }
  