import org.bouncycastle.crypto.macs.HMac;
import org.bouncycastle.crypto.params.KDFCounterParameters;

/**
 * SMB3 SP800-108 Counter Mode Key Derivation
 *
 * @author mbechler
 *
 */
public final class Smb3KeyDerivation {

    private static final byte[] SIGNCONTEXT_300 = toCBytes("SmbSign");
    private static final byte[] SIGNLABEL_300 = toCBytes("SMB2AESCMAC");
    private static final byte[] SIGNLABEL_311 = toCBytes("SMBSigningKey");

        // When
        byte[] signingKey = Smb3KeyDerivation.deriveSigningKey(dialect, sessionKey, preauthIntegrity);
        byte[] appKey = Smb3KeyDerivation.dervieApplicationKey(dialect, sessionKey, preauthIntegrity);
        byte[] encKey = Smb3KeyDerivation.deriveEncryptionKey(dialect, sessionKey, preauthIntegrity);
        byte[] decKey = Smb3KeyDerivation.deriveDecryptionKey(dialect, sessionKey, preauthIntegrity);

        void testConstructorSmb300() throws GeneralSecurityException {
            try (MockedStatic<Smb3KeyDerivation> mockedKeyDerivation = mockStatic(Smb3KeyDerivation.class)) {
                byte[] derivedKey = new byte[16];
                Arrays.fill(derivedKey, (byte) 0xCC);
                mockedKeyDerivation.when(
                        () -> Smb3KeyDerivation.deriveSigningKey(eq(Smb2Constants.SMB2_DIALECT_0300), any(byte[].class), any(byte[].class)))

            this.signingKey = sessionKey.clone();
            break;
        case Smb2Constants.SMB2_DIALECT_0300:
        case Smb2Constants.SMB2_DIALECT_0302:
            this.signingKey = Smb3KeyDerivation.deriveSigningKey(dialect, sessionKey, new byte[0] /* unimplemented */);
            this.algorithmName = "AESCMAC";
            this.provider = Crypto.getProvider();
            break;

        final int dialectInt = dialect.getDialect();
        final byte[] newEncryptionKey = Smb3KeyDerivation.deriveEncryptionKey(dialectInt, modifiedSessionKey, preauthIntegrityHash);
        final byte[] newDecryptionKey = Smb3KeyDerivation.deriveDecryptionKey(dialectInt, modifiedSessionKey, preauthIntegrityHash);

        // Securely wipe the modified session key

        new SecureRandom().nextBytes(preauthHash);

        // Derive initial keys
        int dialectInt = DialectVersion.SMB311.getDialect();
        byte[] encKey = Smb3KeyDerivation.deriveEncryptionKey(dialectInt, sessionKey, preauthHash);
        byte[] decKey = Smb3KeyDerivation.deriveDecryptionKey(dialectInt, sessionKey, preauthHash);

        // Create context with session key for auto-rotation

            // Derive encryption and decryption keys using SMB3 KDF
            final int dialectInt = dialect.getDialect();
            final byte[] encryptionKey = Smb3KeyDerivation.deriveEncryptionKey(dialectInt, sessionKey, preauthHash);
            final byte[] decryptionKey = Smb3KeyDerivation.deriveDecryptionKey(dialectInt, sessionKey, preauthHash);

            // Pass session key and preauthHash to enable automatic key rotation