source: osm/applications/editors/josm/plugins/native-password-manager/src/org/netbeans/modules/keyring/fallback/FallbackProvider.java@ 26335

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 * Portions Copyrighted 2009 Sun Microsystems, Inc.
 */

package org.netbeans.modules.keyring.fallback;

import java.util.UUID;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.netbeans.modules.keyring.impl.Utils;
import org.netbeans.modules.keyring.spi.EncryptionProvider;
import org.netbeans.spi.keyring.KeyringProvider;

/**
 * Platform-independent keyring provider using a master password and the user directory.
 */
public class FallbackProvider implements KeyringProvider {

    private static final Logger LOG = Logger.getLogger(FallbackProvider.class.getName());
    private static final String DESCRIPTION = ".description";
    private static final String SAMPLE_KEY = "__sample__";

    private EncryptionProvider encryption;
    private IPreferences pre;
    
    // simple interface for a generic preferences store
    public interface IPreferences {
        String get(String key, String def);
        void put(String key, String val);
        void remove(String key);
    }

    public FallbackProvider(EncryptionProvider encryption, IPreferences pref) {
        this.encryption = encryption;
        this.pre = pref;
    }
    
    public boolean enabled() {
        if (encryption.enabled()) {
            if (testSampleKey()) {
                LOG.log(Level.FINE, "Using provider: {0}", encryption);
                return true;
            }
        }
        LOG.fine("No provider");
        return false;
    }
    
    private boolean testSampleKey() {
        encryption.freshKeyring(true);
        if (_save(SAMPLE_KEY, (SAMPLE_KEY + UUID.randomUUID()).toCharArray(),
                "Sample value ensuring that decryption is working.")) {
            LOG.fine("saved sample key");
            return true;
        } else {
            LOG.fine("could not save sample key");
            return false;
        }
    }

    public char[] read(String key) {
        String ciphertext_string = pre.get(key, null);
        byte[] ciphertext = ciphertext_string == null ? null : Utils.chars2Bytes(ciphertext_string.toCharArray());
        if (ciphertext == null) {
            return null;
        }
        try {
            return encryption.decrypt(ciphertext);
        } catch (Exception x) {
            LOG.log(Level.FINE, "failed to decrypt password for " + key, x);
        }
        return null;
    }

    public void save(String key, char[] password, String description) {
        _save(key, password, description);
    }
    private boolean _save(String key, char[] password, String description) {
        try {
            byte[] encryptedPasswordByteArray = encryption.encrypt(password);
            String encryptedPassword = encryptedPasswordByteArray == null ? null : String.valueOf(Utils.bytes2Chars(encryptedPasswordByteArray));
            pre.put(key, encryptedPassword);
        } catch (Exception x) {
            LOG.log(Level.FINE, "failed to encrypt password for " + key, x);
            return false;
        }
        if (description != null) {
            // Preferences interface gives no access to *.properties comments, so:
            pre.put(key + DESCRIPTION, description);
        }
        return true;
    }

    public void delete(String key) {
        pre.remove(key);
        pre.remove(key + DESCRIPTION);
    }

}