github.com/aarzilli/tools@v0.0.0-20151123112009-0d27094f75e0/appengine/login/googlesignin/jwt-go/ecdsa_utils.go (about)

     1  package jwt
     2  
     3  import (
     4  	"crypto/ecdsa"
     5  	"crypto/x509"
     6  	"encoding/pem"
     7  	"errors"
     8  )
     9  
    10  var (
    11  	ErrNotECPublicKey  = errors.New("Key is not a valid ECDSA public key")
    12  	ErrNotECPrivateKey = errors.New("Key is not a valid ECDSA private key")
    13  )
    14  
    15  // Parse PEM encoded Elliptic Curve Private Key Structure
    16  func ParseECPrivateKeyFromPEM(key []byte) (*ecdsa.PrivateKey, error) {
    17  	var err error
    18  
    19  	// Parse PEM block
    20  	var block *pem.Block
    21  	if block, _ = pem.Decode(key); block == nil {
    22  		return nil, ErrKeyMustBePEMEncoded
    23  	}
    24  
    25  	// Parse the key
    26  	var parsedKey interface{}
    27  	if parsedKey, err = x509.ParseECPrivateKey(block.Bytes); err != nil {
    28  		return nil, err
    29  	}
    30  
    31  	var pkey *ecdsa.PrivateKey
    32  	var ok bool
    33  	if pkey, ok = parsedKey.(*ecdsa.PrivateKey); !ok {
    34  		return nil, ErrNotECPrivateKey
    35  	}
    36  
    37  	return pkey, nil
    38  }
    39  
    40  // Parse PEM encoded PKCS1 or PKCS8 public key
    41  func ParseECPublicKeyFromPEM(key []byte) (*ecdsa.PublicKey, error) {
    42  	var err error
    43  
    44  	// Parse PEM block
    45  	var block *pem.Block
    46  	if block, _ = pem.Decode(key); block == nil {
    47  		return nil, ErrKeyMustBePEMEncoded
    48  	}
    49  
    50  	// Parse the key
    51  	var parsedKey interface{}
    52  	if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err != nil {
    53  		if cert, err := x509.ParseCertificate(block.Bytes); err == nil {
    54  			parsedKey = cert.PublicKey
    55  		} else {
    56  			return nil, err
    57  		}
    58  	}
    59  
    60  	var pkey *ecdsa.PublicKey
    61  	var ok bool
    62  	if pkey, ok = parsedKey.(*ecdsa.PublicKey); !ok {
    63  		return nil, ErrNotECPublicKey
    64  	}
    65  
    66  	return pkey, nil
    67  }