WalletDataVault.java

package org.ripple.power.wallet;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.Key;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.security.Provider;

import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

import org.ripple.bouncycastle.jce.provider.BouncyCastleProvider;

public class WalletDataVault {

	public static final String CIPHER_ALGORITHM = "AES";
	public static final String KEY_ALGORITHM = "AES";
	public static final String PASSWORD_HASH_ALGORITHM = "SHA-256";

	private File file;
	private Provider provider;

	public WalletDataVault(File file) {
		this.file = file;
		this.provider = new BouncyCastleProvider();
	}

	public InputStream getInputStream(char[] password)
			throws NoSuchAlgorithmException, NoSuchPaddingException,
			FileNotFoundException, InvalidKeyException,
			UnsupportedEncodingException {
		Cipher cipher = buildCipher(password, Cipher.DECRYPT_MODE);
		return new CipherInputStream(new FileInputStream(file), cipher);
	}

	public OutputStream getOutputStream(char[] password)
			throws NoSuchAlgorithmException, NoSuchPaddingException,
			FileNotFoundException, InvalidKeyException,
			UnsupportedEncodingException {
		Cipher cipher = buildCipher(password, Cipher.ENCRYPT_MODE);
		return new CipherOutputStream(new FileOutputStream(file), cipher);
	}

	private Cipher buildCipher(char[] password, int mode)
			throws NoSuchAlgorithmException, NoSuchPaddingException,
			InvalidKeyException, UnsupportedEncodingException {
		Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM, provider);
		Key key = buildKey(password);
		cipher.init(mode, key);
		return cipher;
	}

	private Key buildKey(char[] password) throws NoSuchAlgorithmException,
			UnsupportedEncodingException {
		MessageDigest digester = MessageDigest.getInstance(
				PASSWORD_HASH_ALGORITHM, provider);
		digester.update(String.valueOf(password).getBytes("UTF-8"));
		byte[] key = digester.digest();
		SecretKeySpec spec = new SecretKeySpec(key, KEY_ALGORITHM);
		return spec;
	}
}