protected <T extends KeySpec> T engineGetKeySpec(Key key, Class<T> keySpec)
throws InvalidKeySpecException {
try {
// convert key to one of our keys
// this also verifies that the key is a valid RSA key and ensures
// that the encoding is X.509/PKCS#8 for public/private keys
key = engineTranslateKey(key);
} catch (InvalidKeyException e) {
throw new InvalidKeySpecException(e);
}
if (key instanceof RSAPublicKey) {
RSAPublicKey rsaKey = (RSAPublicKey) key;
if (rsaPublicKeySpecClass.isAssignableFrom(keySpec)) {
return keySpec.cast(new RSAPublicKeySpec(rsaKey.getModulus(), rsaKey.getPublicExponent()));
} else if (x509KeySpecClass.isAssignableFrom(keySpec)) {
return keySpec.cast(new X509EncodedKeySpec(key.getEncoded()));
} else {
throw new InvalidKeySpecException(
"KeySpec must be RSAPublicKeySpec or " + "X509EncodedKeySpec for RSA public keys");
}
} else if (key instanceof RSAPrivateKey) {
if (pkcs8KeySpecClass.isAssignableFrom(keySpec)) {
return keySpec.cast(new PKCS8EncodedKeySpec(key.getEncoded()));
} else if (rsaPrivateCrtKeySpecClass.isAssignableFrom(keySpec)) {
if (key instanceof RSAPrivateCrtKey) {
RSAPrivateCrtKey crtKey = (RSAPrivateCrtKey) key;
return keySpec.cast(
new RSAPrivateCrtKeySpec(
crtKey.getModulus(),
crtKey.getPublicExponent(),
crtKey.getPrivateExponent(),
crtKey.getPrimeP(),
crtKey.getPrimeQ(),
crtKey.getPrimeExponentP(),
crtKey.getPrimeExponentQ(),
crtKey.getCrtCoefficient()));
} else {
throw new InvalidKeySpecException("RSAPrivateCrtKeySpec can only be used with CRT keys");
}
} else if (rsaPrivateKeySpecClass.isAssignableFrom(keySpec)) {
RSAPrivateKey rsaKey = (RSAPrivateKey) key;
return keySpec.cast(
new RSAPrivateKeySpec(rsaKey.getModulus(), rsaKey.getPrivateExponent()));
} else {
throw new InvalidKeySpecException(
"KeySpec must be RSAPrivate(Crt)KeySpec or "
+ "PKCS8EncodedKeySpec for RSA private keys");
}
} else {
// should not occur, caught in engineTranslateKey()
throw new InvalidKeySpecException("Neither public nor private key");
}
}
// internal implementation of translateKey() for public keys. See JCA doc
private PublicKey translatePublicKey(PublicKey key) throws InvalidKeyException {
if (key instanceof RSAPublicKey) {
if (key instanceof RSAPublicKeyImpl) {
return key;
}
RSAPublicKey rsaKey = (RSAPublicKey) key;
try {
return new RSAPublicKeyImpl(rsaKey.getModulus(), rsaKey.getPublicExponent());
} catch (RuntimeException e) {
// catch providers that incorrectly implement RSAPublicKey
throw new InvalidKeyException("Invalid key", e);
}
} else if ("X.509".equals(key.getFormat())) {
byte[] encoded = key.getEncoded();
return new RSAPublicKeyImpl(encoded);
} else {
throw new InvalidKeyException(
"Public keys must be instance " + "of RSAPublicKey or have X.509 encoding");
}
}