Decrypt a SQLCipher database to a Plaintext Database

[chen li]

hi, i have a problem while follow the link as:

http://sqlcipher.net/sqlcipher-api/#key

and

http://sqlcipher.net/sqlcipher-for-android/

while executing

database.execSQL("ATTACH DATABASE '/data/data/com.SqlcipherSample/
databases/plaintext.db' AS plaintext KEY '';");

it keeping telling me that


05-04 19:00:02.312: ERROR/AndroidRuntime(16691): Caused by:
info.guardianproject.database.sqlcipher.SQLiteException: unable to
open database: plaintext.db: ATTACH DATABASE 'plaintext.db' AS
plaintext KEY '';

below is my complete file, is there any way to fix it?

Thanks very much.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

package com.SqlcipherSample;

import java.io.File;
import java.io.IOException;

import android.app.Activity;
import info.guardianproject.database.sqlcipher.SQLiteDatabase;
import android.os.Bundle;

public class main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
InitializeSQLCipher();
}

private void InitializeSQLCipher() {
SQLiteDatabase.loadLibs(this);
File databaseFile = getDatabasePath("demo.db");
databaseFile.mkdirs();
databaseFile.delete();
SQLiteDatabase database =
SQLiteDatabase.openOrCreateDatabase(databaseFile, "test123", null);
database.execSQL("create table t1(a, b)");
database.execSQL("insert into t1(a, b) values(?, ?)", new
Object[]{"one for the money",

"two for the show"});

File plaintextFile = getDatabasePath("plaintext.db");
try {
plaintextFile.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
database.execSQL("PRAGMA key = 'test123'");
database.execSQL("ATTACH DATABASE '/data/data/
com.SqlcipherSample/databases/plaintext.db' AS plaintext KEY '';");
database.execSQL("SELECT sqlcipher_export('plaintext'); ");
database.execSQL("DETACH DATABASE plaintext;");
}
}

[Nick Parker]

Hi Chen,

You shouldn't need to call createNewFile() on the File provided from
getDatabasePath(...). We have a couple of examples attaching both an
existing database as well as attaching with a non-existent database
[1][2]. Also, to use the sqlcipher_export convenience function, you
would need to upgrade your libraries from the 1.1 version you are using
to the 2.0, currently RC5. You can get those binaries here [3].


1.
https://github.com/sqlcipher/sqlcipher-android-tests/blob/master/src/main/java/net/zetetic/tests/AttachExistingDatabaseTest.java
2.
https://github.com/sqlcipher/sqlcipher-android-tests/blob/master/src/main/java/net/zetetic/tests/AttachNewDatabaseTest.java
3.
https://github.com/downloads/sqlcipher/android-database-sqlcipher/SQLCipher%20for%20Android%202.0.0-RC5.zip

--
Nick Parker

[chen li]

So Great, Nick, you are wonderful!!

i follow what you said, and it works. I will try some big sqlite
legacy database (>1mb) for our development. any good suggestions?

BTW, below is my code:

~~~~~~~~~~~~~~~~~~~~~

package com.SqlcipherSample;

import java.io.File;
import java.io.IOException;

import net.sqlcipher.database.SQLiteDatabase;

import android.app.Activity;

import android.os.Bundle;

public class main extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
InitializeSQLCipher();
}

private void InitializeSQLCipher() {
SQLiteDatabase.loadLibs(this);
File databaseFile = getDatabasePath("demo.db");
databaseFile.mkdirs();
databaseFile.delete();
SQLiteDatabase database =
SQLiteDatabase.openOrCreateDatabase(databaseFile, "test123", null);
database.execSQL("create table t1(a, b)");
database.execSQL("insert into t1(a, b) values(?, ?)", new
Object[]{"one for the money",

"two for the show"});

/*

File plaintextFile = getDatabasePath("plaintext.db");
try {
plaintextFile.createNewFile();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();

}*/

database.execSQL("PRAGMA key = 'test123'");
database.execSQL("ATTACH DATABASE '/data/data/
com.SqlcipherSample/databases/plaintext.db' AS plaintext KEY '';");

database.rawQuery("SELECT sqlcipher_export('plaintext');",
null);

> 1.https://github.com/sqlcipher/sqlcipher-android-tests/blob/master/src/...
> 2.https://github.com/sqlcipher/sqlcipher-android-tests/blob/master/src/...
> 3.https://github.com/downloads/sqlcipher/android-database-sqlcipher/SQL...

[chen li]

Problems again...

Above, i had successfully migrate a new created encrypted database to
non-encryted database.

but when i tried migrating a legacy sqlite to encrypted, it shows no
errors, but the new db file is 0 byte...

is there any problems, please?

below is my code:

~~~~~~~~~~~~~~~~~~~~~~~

private void create(Context c){
//db=null;
try
{
String dirName="/data/data/"+c.getPackageName() + "/";//
getString(R.string.DATABASE_PATH);
String databaseFileName = "1.db"; // the existing sqlite,
400k
if (!sDatabaseFileName.equals("")){
databaseFileName = sDatabaseFileName;
}
sDatabaseFileName = databaseFileName;
File dbFile = c.getDatabasePath(databaseFileName);
String fullDBName = dbFile.getAbsolutePath();
if(!dbFile.exists()){
dbFile.createNewFile();

InputStream is =
c.getResources().openRawResource(R.raw.laiqian);
FileOutputStream fos = new FileOutputStream(fullDBName);
byte[] buffer = new byte[8192];
int count=0;
while((count=is.read(buffer))>0)
{
fos.write(buffer,0,count);
}
fos.close();
is.close();
}

//SQLiteDatabase.loadLibs(c);
db = SQLiteDatabase.openOrCreateDatabase(fullDBName,"",null);
//db.rawExecSQL("PRAGMA key = ''");
Cursor c1 = db.rawQuery("SELECT count(*) FROM t_string;", null);
c1.moveToFirst();
Toast.makeText(c, c1.getString(0), Toast.LENGTH_SHORT).show();//
it works
//move it to a new encrypted database
//db.execSQL("PRAGMA key = ''");
File newDatabasePath = c.getDatabasePath("encryted.db");
//db.rawExecSQL("pragma cipher_default_use_hmac = off");
db.execSQL("PRAGMA key = '';");
db.execSQL("ATTACH DATABASE '"+newDatabasePath.getAbsolutePath()
+"' AS encrypt1 KEY '123456';");
db.rawQuery("SELECT sqlcipher_export('encrypt1');", null);
db.execSQL("DETACH DATABASE encrypt1;");
}
catch (Exception e){
e.printStackTrace();

[Georgie Casey]

Chen,

You're getting pretty good, quick, and *free* support already so I
wouldn't double post because you didn't get a reply within 3 hours.

I didn't go through all your code, it looks like it was copied and
pasted from various corner of the Internet. But I do see straightaway
that you attach a database called 'encryted.db' then try and export a
database called 'encrypt1' so fix that first of all and come back with
the inevitable errors. And you've a catch in your code so your code
won't crash but there should be something in your LogCat, copy that
here as well if you want help.

Georgie

[Nick Parker]

Hi Chen,

Since you are now using the 2.0 RC version of the libraries, we have
included a class method off the SQLiteDatabase class called
upgradeDatabaseFormatFromVersion1To2, you should consider using that to
perform a migration to a new encrypted database. If you choose not to
do so, you may consider calling rawExecSQL when executing the
sqlcipher_export convenience method. This will keep certain SQL queries
from bubbling up an exception when sqlite3_step does not return
SQLITE_ROW. Finally can you confirm that your source database contains
data to migrate before the upgrade process. Thanks!

--
Nick Parker