src/jdk.crypto.mscapi/windows/classes/sun/security/mscapi/CKeyPairGenerator.java

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package sun.security.mscapi;

import java.util.UUID;
import java.security.*;
import java.security.spec.AlgorithmParameterSpec;
import java.security.spec.RSAKeyGenParameterSpec;

import sun.security.rsa.RSAKeyFactory;
import static sun.security.util.SecurityProviderConstants.DEF_RSA_KEY_SIZE;

/**
 * RSA keypair generator.
 *
 * Standard algorithm, minimum key length is 512 bit, maximum is 16,384.
 * Generates a private key that is exportable.
 *
 * @since 1.6
 */
public abstract class CKeyPairGenerator extends KeyPairGeneratorSpi {

    protected String keyAlg;

    public CKeyPairGenerator(String keyAlg) {
        this.keyAlg = keyAlg;
    }

    public static class RSA extends CKeyPairGenerator {
        public RSA() {
            super("RSA");
            // initialize to default in case the app does not call initialize()
            initialize(DEF_RSA_KEY_SIZE, null);
        }

        // Supported by Microsoft Base, Strong and Enhanced Cryptographic Providers
        static final int KEY_SIZE_MIN = 512; // disallow MSCAPI min. of 384
        static final int KEY_SIZE_MAX = 16384;

        // size of the key to generate, KEY_SIZE_MIN <= keySize <= KEY_SIZE_MAX
        private int keySize;

        // initialize the generator. See JCA doc
        // random is always ignored
        @Override
        public void initialize(int keySize, SecureRandom random) {

            try {
                RSAKeyFactory.checkKeyLengths(keySize, null,
                        KEY_SIZE_MIN, KEY_SIZE_MAX);
            } catch (InvalidKeyException e) {
                throw new InvalidParameterException(e);
            }

            this.keySize = keySize;
        }

        // second initialize method. See JCA doc
        // random and exponent are always ignored
        @Override
        public void initialize(AlgorithmParameterSpec params, SecureRandom random)
                throws InvalidAlgorithmParameterException {

            int tmpSize;
            if (params == null) {
                tmpSize = DEF_RSA_KEY_SIZE;
            } else if (params instanceof RSAKeyGenParameterSpec) {

                if (((RSAKeyGenParameterSpec) params).getPublicExponent() != null) {
                    throw new InvalidAlgorithmParameterException
                            ("Exponent parameter is not supported");
                }
                tmpSize = ((RSAKeyGenParameterSpec) params).getKeysize();

            } else {
                throw new InvalidAlgorithmParameterException
                        ("Params must be an instance of RSAKeyGenParameterSpec");
            }

            try {
                RSAKeyFactory.checkKeyLengths(tmpSize, null,
                        KEY_SIZE_MIN, KEY_SIZE_MAX);
            } catch (InvalidKeyException e) {
                throw new InvalidAlgorithmParameterException(
                        "Invalid Key sizes", e);
            }

            this.keySize = tmpSize;
        }

        // generate the keypair. See JCA doc
        @Override
        public KeyPair generateKeyPair() {

            try {
                // Generate each keypair in a unique key container
                CKeyPair keys =
                        generateCKeyPair(keyAlg, keySize,
                                "{" + UUID.randomUUID().toString() + "}");
                return new KeyPair(keys.getPublic(), keys.getPrivate());

            } catch (KeyException e) {
                throw new ProviderException(e);
            }
        }

        private static native CKeyPair generateCKeyPair(String alg, int keySize,
                String keyContainerName) throws KeyException;
    }
}