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package jose
import (
"errors"
"crypto/rsa"
"crypto/rand"
"hash"
"crypto/sha1"
"crypto/sha256"
"github.com/dvsekhvalnov/jose2go/arrays"
)
// RS-AES using OAEP key management algorithm implementation
func init() {
RegisterJwa(&RsaOaep {shaSizeBits:1})
RegisterJwa(&RsaOaep {shaSizeBits:256})
}
type RsaOaep struct{
shaSizeBits int
// func shaF() hash.Hash
}
func (alg *RsaOaep) Name() string {
switch alg.shaSizeBits {
case 1: return RSA_OAEP
default: return RSA_OAEP_256
}
}
func (alg *RsaOaep) WrapNewKey(cekSizeBits int, key interface{}, header map[string]interface{}) (cek []byte, encryptedCek []byte, err error) {
if pubKey,ok:=key.(*rsa.PublicKey);ok {
if cek,err = arrays.Random(cekSizeBits>>3);err==nil {
encryptedCek,err=rsa.EncryptOAEP(alg.sha(),rand.Reader,pubKey,cek,nil)
return
}
return nil,nil,err
}
return nil,nil,errors.New("RsaOaep.WrapNewKey(): expected key to be '*rsa.PublicKey'")
}
func (alg *RsaOaep) Unwrap(encryptedCek []byte, key interface{}, cekSizeBits int, header map[string]interface{}) (cek []byte, err error) {
if privKey,ok:=key.(*rsa.PrivateKey);ok {
return rsa.DecryptOAEP(alg.sha(), rand.Reader, privKey, encryptedCek, nil)
}
return nil,errors.New("RsaOaep.Unwrap(): expected key to be '*rsa.PrivateKey'")
}
func (alg *RsaOaep) sha() hash.Hash {
switch alg.shaSizeBits {
case 1: return sha1.New()
default: return sha256.New()
}
}
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