我正在使用SQLiteCipher来加密我的数据库。以前，我使用的是db.execsql()语句，效果很好。现在，我将查询更改为SQLStatment。
这是我的代码
private static void encrypt(Context ctxt) {
File originalFile = ctxt.getDatabasePath(DBNAME);
if (originalFile.exists()) {
File newFile;
try {
newFile = File.createTempFile("sqlcipherutils", "tmp", ctxt.getCacheDir());
SQLiteDatabase db = SQLiteDatabase.openDatabase(originalFile.getAbsolutePath(), "", null, SQLiteDatabase.OPEN_READWRITE);
SQLiteStatement preparedStatement = db.compileStatement("ATTACH DATABASE ? AS encrypted KEY ?");
preparedStatement.bindString(1, newFile.getAbsolutePath());
preparedStatement.bindString(2, DataControllers.getDbKey());
preparedStatement.execute();
SQLiteStatement preparedStatement1= db.compileStatement("SELECT sqlcipher_export('encrypted')");
preparedStatement1.execute();
SQLiteStatement preparedStatement2= db.compileStatement("DETACH DATABASE encrypted");
preparedStatement2.execute();
int version = db.getVersion();
db.close();
db = SQLiteDatabase.openDatabase(newFile.getAbsolutePath(), DataControllers.getDbKey(), null, SQLiteDatabase.OPEN_READWRITE);
db.setVersion(version);
db.close();
originalFile.delete();
newFile.renameTo(originalFile);
} catch (IOException e) {
e.printStackTrace();
}
}
}
第一个执行语句运行，但是第二个执行语句抛出异常。
这是堆栈跟踪
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.package/com.package.ui.Dashboard}: net.sqlcipher.database.SQLiteException: error code 100: another row available
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2327)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2392)
at android.app.ActivityThread.access$800(ActivityThread.java:153)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1305)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5293)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:903)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:698)
Caused by: net.sqlcipher.database.SQLiteException: error code 100: another row available
at net.sqlcipher.database.SQLiteStatement.native_execute(Native Method)
at net.sqlcipher.database.SQLiteStatement.execute(SQLiteStatement.java:58)
at com.package.dbconnections.DatabaseOpenHelper.encrypt(DatabaseOpenHelper.java:172)
at com.package.dbconnections.DatabaseOpenHelper.isDbEncrypted(DatabaseOpenHelper.java:151)
at com.package.dbconnections.DatabaseOpenHelper.getInstance(DatabaseOpenHelper.java:136)
at com.package.dbconnections.DatabaseOpenHelper.getUrls(DatabaseOpenHelper.java:605)
答案 0 :(得分：1)
我认为唯一的解决方法是使用专门创建的 rawExecSQL 方法。
不能使用。由于安全性问题而未处理或rawExecSQL
使用此方法没有安全性问题，因为没有用户输入，因此没有机会进行SQL注入。也许见SQL injection。
我认为问题在于，通常exec / execute允许有限的结果，rawQuery / query将返回Cursor。我相信该转换可能会生成SQL，通过对数据进行加密来对其进行修改，然后将所得的SQL作为语句流执行（因此，尝试使用execute时，错误代码为100）。需要一种特殊的方法（因此 rawExecSQL ），因为大多数内置方法只允许运行一条语句。
这是一个可行的示例，其他尝试都将结果注释掉（如果尝试使用 SQLiteStatement ，则包括错误代码100）
。该示例创建了 normal 数据库，加载了一些数据，提取并转储了这些数据（以进行比较/验证），并使用现有的android SQLiteDatabase方法将其关闭。
然后使用SQlCipher openorcreate方法创建加密的数据库，然后立即将其关闭（从而创建文件）。
然后使用SQLCipher方法打开 normal 数据库，然后附加新创建的空 encrypted 数据库，然后进行转换并进行 encrypted 数据库已分离。然后 normal 关闭。
最后，打开新的加密数据库，提取并转储数据（用于比较/验证）。
代码是：-
public class MainActivity extends AppCompatActivity {
String normaldbname = "mydb";
String encrypteddbname = "myencrypteddb";
String password = "thepassword";
String tablename = "mytable";
String idcolumn = BaseColumns._ID;
String namecolumn = "name";
String[] namelist = new String[]{
"Fred","Anne","Jane","John",
};
SQLiteDatabase normaldb;
net.sqlcipher.database.SQLiteDatabase normal_for_encryption;
net.sqlcipher.database.SQLiteDatabase encrypteddb;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
net.sqlcipher.database.SQLiteDatabase.loadLibs(this);
normaldb = SQLiteDatabase.openOrCreateDatabase(this.getDatabasePath(normaldbname).getPath(),null);
normaldb.execSQL("CREATE TABLE IF NOT EXISTS " + tablename + " (" +
idcolumn +
" INTEGER PRIMARY KEY, " +
namecolumn +
" TEXT)");
ContentValues cv = new ContentValues();
normaldb.beginTransaction();
//for (int i=0; i < 1000; i++) { for larger test
for (String name : namelist) {
cv.clear();
cv.put(namecolumn, name);
normaldb.insert(tablename, null, cv);
}
//}
normaldb.setTransactionSuccessful();
normaldb.endTransaction();
DatabaseUtils.dumpCursor(
normaldb.query(tablename,null,null,null,null,null,null)
);
normaldb.close();
net.sqlcipher.database.SQLiteDatabase.openOrCreateDatabase(this.getDatabasePath(encrypteddbname).getPath(),password,null).close();
normal_for_encryption = net.sqlcipher.database.SQLiteDatabase.openDatabase(
this.getDatabasePath(normaldbname).getPath(),
"",null,
net.sqlcipher.database.SQLiteDatabase.OPEN_READWRITE
);
net.sqlcipher.database.SQLiteStatement stmnt = normal_for_encryption.compileStatement("ATTACH DATABASE ? AS encrypted KEY ?");
stmnt.bindString(1,this.getDatabasePath(encrypteddbname).getPath());
stmnt.bindString(2,password);
stmnt.execute();
/* Ouch net.sqlcipher.database.SQLiteException: error code 100: another row available
net.sqlcipher.database.SQLiteStatement stmnt2 = normal_for_encryption.compileStatement("SELECT sqlcipher_export('encrypted')");
stmnt2.execute();
*/
//normal_for_encryption.rawQuery("SELECT sqlcipher_export('encrypted')",null); //<<<<<<<<< Ouch no such table: mytable: , while compiling: SELECT * FROM mytable
//normal_for_encryption.execSQL("SELECT sqlcipher_export('encrypted')"); //<<<<<<<<< Ouch net.sqlcipher.database.SQLiteException: unknown error: Queries cannot be performed using execSQL(), use query() instead.
normal_for_encryption.rawExecSQL("SELECT sqlcipher_export('encrypted')"); //<<<<<<<<< WORKS >>>>>>>>>>
normal_for_encryption.execSQL("DETACH DATABASE encrypted");
normal_for_encryption.close();
encrypteddb = net.sqlcipher.database.SQLiteDatabase.openDatabase(
this.getDatabasePath(encrypteddbname).getPath(),
password,null,
net.sqlcipher.database.SQLiteDatabase.OPEN_READWRITE
);
net.sqlcipher.DatabaseUtils.dumpCursor(
encrypteddb.query(tablename,null,null,null,null,null,null)
);
encrypteddb.close();
}
}
2019-05-14 21:10:54.032 I/System.out: >>>>> Dumping cursor android.database.sqlite.SQLiteCursor@c237ffc
2019-05-14 21:10:54.032 I/System.out: 0 {
2019-05-14 21:10:54.032 I/System.out: _id=1
2019-05-14 21:10:54.032 I/System.out: name=Fred
2019-05-14 21:10:54.032 I/System.out: }
2019-05-14 21:10:54.032 I/System.out: 1 {
2019-05-14 21:10:54.032 I/System.out: _id=2
2019-05-14 21:10:54.033 I/System.out: name=Anne
2019-05-14 21:10:54.033 I/System.out: }
2019-05-14 21:10:54.033 I/System.out: 2 {
2019-05-14 21:10:54.033 I/System.out: _id=3
2019-05-14 21:10:54.033 I/System.out: name=Jane
2019-05-14 21:10:54.033 I/System.out: }
2019-05-14 21:10:54.033 I/System.out: 3 {
2019-05-14 21:10:54.034 I/System.out: _id=4
2019-05-14 21:10:54.034 I/System.out: name=John
2019-05-14 21:10:54.034 I/System.out: }
2019-05-14 21:10:54.034 I/System.out: <<<<<
2019-05-14 21:10:54.871 I/System.out: >>>>> Dumping cursor net.sqlcipher.CrossProcessCursorWrapper@1bff13d
2019-05-14 21:10:54.872 I/System.out: 0 {
2019-05-14 21:10:54.872 I/System.out: _id=1
2019-05-14 21:10:54.872 I/System.out: name=Fred
2019-05-14 21:10:54.872 I/System.out: }
2019-05-14 21:10:54.872 I/System.out: 1 {
2019-05-14 21:10:54.872 I/System.out: _id=2
2019-05-14 21:10:54.872 I/System.out: name=Anne
2019-05-14 21:10:54.872 I/System.out: }
2019-05-14 21:10:54.872 I/System.out: 2 {
2019-05-14 21:10:54.872 I/System.out: _id=3
2019-05-14 21:10:54.872 I/System.out: name=Jane
2019-05-14 21:10:54.872 I/System.out: }
2019-05-14 21:10:54.873 I/System.out: 3 {
2019-05-14 21:10:54.873 I/System.out: _id=4
2019-05-14 21:10:54.873 I/System.out: name=John
2019-05-14 21:10:54.873 I/System.out: }
2019-05-14 21:10:54.873 I/System.out: <<<<<