jwt/rs256.go

55 lines
1.2 KiB
Go

package jwt
import (
"errors"
"encoding/base64"
"encoding/pem"
"crypto"
"crypto/x509"
"crypto/rsa"
"crypto/sha256"
)
type SigningMethodRS256 struct {}
func init() {
RegisterSigningMethod("RS256", func() SigningMethod {
return new(SigningMethodRS256)
})
}
func (m *SigningMethodRS256) Verify(signingString, signature string, key []byte)(err error) {
// len % 4
switch len(signature) % 4 {
case 2:
signature = signature + "=="
case 3:
signature = signature + "==="
}
// Key
var sig []byte
if sig, err = base64.URLEncoding.DecodeString(signature); err == nil {
var block *pem.Block
if block, _ = pem.Decode(key); block != nil {
var parsedKey interface{}
if parsedKey, err = x509.ParsePKIXPublicKey(block.Bytes); err == nil {
if rsaKey, ok := parsedKey.(*rsa.PublicKey); ok {
hasher := sha256.New()
hasher.Write([]byte(signingString))
err = rsa.VerifyPKCS1v15(rsaKey, crypto.SHA256, hasher.Sum(nil), sig)
} else {
err = errors.New("Key is not a valid RSA public key")
}
}
} else {
err = errors.New("Could not parse key data")
}
}
return
}
func (m *SigningMethodRS256) Sign(token, key []byte)error {
return nil
}