Convert to gradle build system

1 files changed, 205 insertions, 0 deletions

diff --git a/app/src/main/java/org/connectbot/util/Encryptor.java b/app/src/main/java/org/connectbot/util/Encryptor.java
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+++ b/app/src/main/java/org/connectbot/util/Encryptor.java
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+/*
+ * ConnectBot: simple, powerful, open-source SSH client for Android
+ * Copyright 2007 Kenny Root, Jeffrey Sharkey
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.connectbot.util;
+
+/**
+ * This class is from:
+ *
+ * Encryptor.java
+ * Copyright 2008 Zach Scrivena
+ * zachscrivena@gmail.com
+ * http://zs.freeshell.org/
+ */
+
+import java.security.MessageDigest;
+import java.security.SecureRandom;
+import java.util.Arrays;
+
+import javax.crypto.Cipher;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+
+/**
+ * Perform AES-128 encryption.
+ */
+public final class Encryptor
+{
+	/** name of the character set to use for converting between characters and bytes */
+	private static final String CHARSET_NAME = "UTF-8";
+
+	/** random number generator algorithm */
+	private static final String RNG_ALGORITHM = "SHA1PRNG";
+
+	/** message digest algorithm (must be sufficiently long to provide the key and initialization vector) */
+	private static final String DIGEST_ALGORITHM = "SHA-256";
+
+	/** key algorithm (must be compatible with CIPHER_ALGORITHM) */
+	private static final String KEY_ALGORITHM = "AES";
+
+	/** cipher algorithm (must be compatible with KEY_ALGORITHM) */
+	private static final String CIPHER_ALGORITHM = "AES/CBC/PKCS5Padding";
+
+
+	/**
+	* Private constructor that should never be called.
+	*/
+	private Encryptor()
+	{}
+
+
+	/**
+	* Encrypt the specified cleartext using the given password.
+	* With the correct salt, number of iterations, and password, the decrypt() method reverses
+	* the effect of this method.
+	* This method generates and uses a random salt, and the user-specified number of iterations
+	* and password to create a 16-byte secret key and 16-byte initialization vector.
+	* The secret key and initialization vector are then used in the AES-128 cipher to encrypt
+	* the given cleartext.
+	*
+	* @param salt
+	*	  salt that was used in the encryption (to be populated)
+	* @param iterations
+	*	  number of iterations to use in salting
+	* @param password
+	*	  password to be used for encryption
+	* @param cleartext
+	*	  cleartext to be encrypted
+	* @return
+	*	  ciphertext
+	* @throws Exception
+	*	  on any error encountered in encryption
+	*/
+	public static byte[] encrypt(
+			final byte[] salt,
+			final int iterations,
+			final String password,
+			final byte[] cleartext)
+			throws Exception
+	{
+		/* generate salt randomly */
+		SecureRandom.getInstance(RNG_ALGORITHM).nextBytes(salt);
+
+		/* compute key and initialization vector */
+		final MessageDigest shaDigest = MessageDigest.getInstance(DIGEST_ALGORITHM);
+		byte[] pw = password.getBytes(CHARSET_NAME);
+
+		for (int i = 0; i < iterations; i++)
+		{
+			/* add salt */
+			final byte[] salted = new byte[pw.length + salt.length];
+			System.arraycopy(pw, 0, salted, 0, pw.length);
+			System.arraycopy(salt, 0, salted, pw.length, salt.length);
+			Arrays.fill(pw, (byte) 0x00);
+
+			/* compute SHA-256 digest */
+			shaDigest.reset();
+			pw = shaDigest.digest(salted);
+			Arrays.fill(salted, (byte) 0x00);
+		}
+
+		/* extract the 16-byte key and initialization vector from the SHA-256 digest */
+		final byte[] key = new byte[16];
+		final byte[] iv = new byte[16];
+		System.arraycopy(pw, 0, key, 0, 16);
+		System.arraycopy(pw, 16, iv, 0, 16);
+		Arrays.fill(pw, (byte) 0x00);
+
+		/* perform AES-128 encryption */
+		final Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
+
+		cipher.init(
+				Cipher.ENCRYPT_MODE,
+				new SecretKeySpec(key, KEY_ALGORITHM),
+				new IvParameterSpec(iv));
+
+		Arrays.fill(key, (byte) 0x00);
+		Arrays.fill(iv, (byte) 0x00);
+
+		return cipher.doFinal(cleartext);
+	}
+
+
+	/**
+	* Decrypt the specified ciphertext using the given password.
+	* With the correct salt, number of iterations, and password, this method reverses the effect
+	* of the encrypt() method.
+	* This method uses the user-specified salt, number of iterations, and password
+	* to recreate the 16-byte secret key and 16-byte initialization vector.
+	* The secret key and initialization vector are then used in the AES-128 cipher to decrypt
+	* the given ciphertext.
+	*
+	* @param salt
+	*	  salt to be used in decryption
+	* @param iterations
+	*	  number of iterations to use in salting
+	* @param password
+	*	  password to be used for decryption
+	* @param ciphertext
+	*	  ciphertext to be decrypted
+	* @return
+	*	  cleartext
+	* @throws Exception
+	*	  on any error encountered in decryption
+	*/
+	public static byte[] decrypt(
+			final byte[] salt,
+			final int iterations,
+			final String password,
+			final byte[] ciphertext)
+			throws Exception
+	{
+		/* compute key and initialization vector */
+		final MessageDigest shaDigest = MessageDigest.getInstance(DIGEST_ALGORITHM);
+		byte[] pw = password.getBytes(CHARSET_NAME);
+
+		for (int i = 0; i < iterations; i++)
+		{
+			/* add salt */
+			final byte[] salted = new byte[pw.length + salt.length];
+			System.arraycopy(pw, 0, salted, 0, pw.length);
+			System.arraycopy(salt, 0, salted, pw.length, salt.length);
+			Arrays.fill(pw, (byte) 0x00);
+
+			/* compute SHA-256 digest */
+			shaDigest.reset();
+			pw = shaDigest.digest(salted);
+			Arrays.fill(salted, (byte) 0x00);
+		}
+
+		/* extract the 16-byte key and initialization vector from the SHA-256 digest */
+		final byte[] key = new byte[16];
+		final byte[] iv = new byte[16];
+		System.arraycopy(pw, 0, key, 0, 16);
+		System.arraycopy(pw, 16, iv, 0, 16);
+		Arrays.fill(pw, (byte) 0x00);
+
+		/* perform AES-128 decryption */
+		final Cipher cipher = Cipher.getInstance(CIPHER_ALGORITHM);
+
+		cipher.init(
+				Cipher.DECRYPT_MODE,
+				new SecretKeySpec(key, KEY_ALGORITHM),
+				new IvParameterSpec(iv));
+
+		Arrays.fill(key, (byte) 0x00);
+		Arrays.fill(iv, (byte) 0x00);
+
+		return cipher.doFinal(ciphertext);
+	}
+}