1 files changed, 97 insertions, 0 deletions
diff --git a/src/main/java/eu/siacs/conversations/services/AbstractConnectionManager.java b/src/main/java/eu/siacs/conversations/services/AbstractConnectionManager.java
index 676a09c9..b7e7c8d3 100644
--- a/src/main/java/eu/siacs/conversations/services/AbstractConnectionManager.java
+++ b/src/main/java/eu/siacs/conversations/services/AbstractConnectionManager.java
@@ -1,5 +1,33 @@
 package eu.siacs.conversations.services;
 
+import android.util.Log;
+import android.util.Pair;
+
+import org.bouncycastle.crypto.engines.AESEngine;
+import org.bouncycastle.crypto.modes.AEADBlockCipher;
+import org.bouncycastle.crypto.modes.GCMBlockCipher;
+import org.bouncycastle.crypto.params.AEADParameters;
+import org.bouncycastle.crypto.params.KeyParameter;
+
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.security.InvalidAlgorithmParameterException;
+import java.security.InvalidKeyException;
+import java.security.NoSuchAlgorithmException;
+
+import javax.crypto.Cipher;
+import javax.crypto.CipherInputStream;
+import javax.crypto.CipherOutputStream;
+import javax.crypto.NoSuchPaddingException;
+import javax.crypto.spec.IvParameterSpec;
+import javax.crypto.spec.SecretKeySpec;
+
+import eu.siacs.conversations.Config;
+import eu.siacs.conversations.entities.DownloadableFile;
+
 public class AbstractConnectionManager {
 	protected XmppConnectionService mXmppConnectionService;
 
@@ -20,4 +48,73 @@ public class AbstractConnectionManager {
 			return 524288;
 		}
 	}
+
+	public static Pair<InputStream,Integer> createInputStream(DownloadableFile file, boolean gcm) {
+		FileInputStream is;
+		int size;
+		try {
+			is = new FileInputStream(file);
+			size = (int) file.getSize();
+			if (file.getKey() == null) {
+				return new Pair<InputStream,Integer>(is,size);
+			}
+		} catch (FileNotFoundException e) {
+			return null;
+		}
+		try {
+			if (gcm) {
+				AEADBlockCipher cipher = new GCMBlockCipher(new AESEngine());
+				cipher.init(true, new AEADParameters(new KeyParameter(file.getKey()), 128, file.getIv()));
+				InputStream cis = new org.bouncycastle.crypto.io.CipherInputStream(is, cipher);
+				return new Pair<>(cis, cipher.getOutputSize(size));
+			} else {
+				IvParameterSpec ips = new IvParameterSpec(file.getIv());
+				Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+				cipher.init(Cipher.ENCRYPT_MODE, new SecretKeySpec(file.getKey(), "AES"), ips);
+				Log.d(Config.LOGTAG, "opening encrypted input stream");
+				return new Pair<InputStream,Integer>(new CipherInputStream(is, cipher),(size / 16 + 1) * 16);
+			}
+		} catch (InvalidKeyException e) {
+			return null;
+		} catch (NoSuchAlgorithmException e) {
+			return null;
+		} catch (NoSuchPaddingException e) {
+			return null;
+		} catch (InvalidAlgorithmParameterException e) {
+			return null;
+		}
+	}
+
+	public static OutputStream createOutputStream(DownloadableFile file, boolean gcm) {
+		FileOutputStream os;
+		try {
+			os = new FileOutputStream(file);
+			if (file.getKey() == null) {
+				return os;
+			}
+		} catch (FileNotFoundException e) {
+			return null;
+		}
+		try {
+			if (gcm) {
+				AEADBlockCipher cipher = new GCMBlockCipher(new AESEngine());
+				cipher.init(false, new AEADParameters(new KeyParameter(file.getKey()), 128, file.getIv()));
+				return new org.bouncycastle.crypto.io.CipherOutputStream(os, cipher);
+			} else {
+				IvParameterSpec ips = new IvParameterSpec(file.getIv());
+				Cipher cipher = Cipher.getInstance("AES/CBC/PKCS5Padding");
+				cipher.init(Cipher.DECRYPT_MODE, new SecretKeySpec(file.getKey(), "AES"), ips);
+				Log.d(Config.LOGTAG, "opening encrypted output stream");
+				return new CipherOutputStream(os, cipher);
+			}
+		} catch (InvalidKeyException e) {
+			return null;
+		} catch (NoSuchAlgorithmException e) {
+			return null;
+		} catch (NoSuchPaddingException e) {
+			return null;
+		} catch (InvalidAlgorithmParameterException e) {
+			return null;
+		}
+	}
 }