How to encrypt databse file

Question

I am using sql server express 2005 for my project along with visual studio
i have created databse file for my project, i wnt to encrypt dthose files using
cryptography technology available in .net framework..i knw it can be done, but dont knw how to do it

if anybody know how to encrypt file, please give me detailes step or link to any such article

thanks in advance

Jorge L Fernandez · Answer

Hi I have corrected both method to make them work. Try this public void EncryptFile(string input string output RijndaelManaged alg1) { FileStream inputStream = new FileStream(inputFileMode.OpenFileAccess.Read); FileStream outputStream = new FileStream(outputFileMode.OpenOrCreateFileAccess.Write); SymmetricAlgorithm alg = new RijndaelManaged(); alg.Key = alg1.Key; alg.IV = alg1.IV; // READ THE DB FILE byte[] data = new byte[inputStream.Length]; inputStream.Read(data0(int)data.Length); ICryptoTransform encryptor = alg.CreateEncryptor(); CryptoStream stream = new CryptoStream(outputStreamencryptorCryptoStreamMode.Write); // WRITE THE DATA ENCRYPTING stream.Write(data0data.Length); // CLOSE SEGMENT stream.Close(); inputStream.Close(); outputStream.Close(); } public void DecryptFile(string input string output RijndaelManaged alg1) { FileStream inputStream = new FileStream(inputFileMode.OpenFileAccess.Read); FileStream outputStream = new FileStream(outputFileMode.OpenOrCreateFileAccess.Write); SymmetricAlgorithm alg = new RijndaelManaged(); alg.Key = alg1.Key; alg.IV = alg1.IV; ICryptoTransform decryptor = alg.CreateDecryptor(); CryptoStream stream = new CryptoStream(inputStreamdecryptorCryptoStreamMode.Read); // READ THE ECRYPTED FILE byte[] data = new byte[inputStream.Length]; // DECRYPT DATA stream.Read(data0(int)inputStream.Length); // WRITE DECRYTED DATA outputStream.Write(data0(int)inputStream.Length); // CLOSE SEGMENT stream.Close(); inputStream.Close(); outputStream.Close(); } Create a file called plain.txt in your exe folder just for testing. Bellow is a test code to test those functions RijndaelManaged alg1 = new RijndaelManaged(); EncryptFile(plain.txtencrypted.txtalg1); DecryptFile(encrypted.txtdecrypted.txtalg1);

kassim · Answer

hey dude thanx for ur reply..it worked for me i just encrypted imp fields of db rather dan db file thanks once again cheers!!!

Jorge L Fernandez · Answer

Hi Kassim You are right. In the code the output variable should be used in here FileStream outputStream = new FileStream(outputFileMode.OpenOrCreateFileAccess.Write); output is the path to save the encrypted file. The key is exaclty that a key that both party (encryptor and decryptor) should know. For example // Encrypt Plain text -> encrypt using key=my key -> encrypted text = lkjljlkjlkjlkjl // Decrypt lkjljlkjlkjlkjl -> decrypt using key=my key -> Plain text if the key is other than my key then we would not be able to get the result back. The longer the key the more difficult to hack due to more possible combinations. Please in decrypt method you should also change the use of output variable. Usually the key is a string converted to a byte array. This both method are usefull to encrypt and decrypt files. You should consider what you really want if fields of databases encrypted or if you want the db files encrypted itself. If you want to encrypt for example a field that stores passwords then you may consider a Hash Algorithm rather than encrypt the whole db file. Hope this helps.

kassim · Answer

thanx for your code it help me to sum extend..but i dint understood sum part of the in encrypt method u dint used output and key variable which is a parameter and what is the role of key in this encryption and waht value i should to use as a key so whenevr i want to load db in appliction i hav to call Decrypt method evrytime???

Amit Choudhary · Answer

hi friend Here is some basic code for encrypting data by using a symmetric key in SQL Server 2005. OPEN SYMMETRIC KEY PrivateData DECRYPTION BY PASSWORD ='Password' CREATE TABLE UserData (Data VARBINARY(255)) DECLARE @Key_GUID UNIQUEIDENTIFIER SELECT @Key_GUID = Key_GUID FROM sys.symmetric_keys WHERE Name = 'PrivateData' INSERT INTO UserData (Data) VALUES (EncryptByKey(@Key_Guid 'RawData' 1)) SELECT Data FROM UserData SELECT CONVERT(VARCHAR(20) DecryptByKey(UserData.Data 1)) AS Data FROM UserData DROP TABLE UserData CLOSE SYMMETRIC KEY PrivateData Enjoy Coding..... =========================================== Don't Forget to mark it as answer :)

Sam Hobbs · Answer

Does How to: Encrypt a Column of Data help?

Jorge L Fernandez · Answer

Hi Since you need to encrypt and decrypt the file representing your DB you may use a symmetric encryption algorithm. The .NET framework provides classes representing such algorithms see System.Security.Cryptography namespace. Basically you will have an input (will by the byte[] representing your file) a key (requiered to decrypt in a latter time) and the byte[] output than can be stored in as a file. check this sample code. It should solve your problem. // ENCRYPT public void EncryptFile(string input string output byte[] key) { FileStream inputStream = new FileStream(inputFileMode.OpenFileAccess.Read); FileStream outputStream = new FileStream(inputFileMode.OpenOrCreateFileAccess.Write); SymmetricAlgorithm alg = new RijndaelManaged(); alg.Key = key; // READ THE DB FILE byte[] data = new byte[inputStream.Length]; inputStream.Read(data0(int)data.Length); ICryptoTransform encryptor = alg.CreateEncryptor(); CryptoStream stream = new CryptoStream(outputStreamencryptorCryptoStreamMode.Write); // WRITE THE DATA ENCRYPTING stream.Write(data0data.Length); // CLOSE SEGMENT stream.Close(); inputStream.Close(); outputStream.Close(); } // DECRYPT public void DecryptFile(string input string output byte[] key) { FileStream inputStream = new FileStream(inputFileMode.OpenFileAccess.Read); FileStream outputStream = new FileStream(inputFileMode.OpenOrCreateFileAccess.Write); SymmetricAlgorithm alg = new RijndaelManaged(); alg.Key = key; // READ THE ECRYPTED FILE byte[] data = new byte[inputStream.Length]; inputStream.Read(data0(int)data.Length); ICryptoTransform decryptor = alg.CreateDecryptor(); CryptoStream stream = new CryptoStream(inputStreamdecryptorCryptoStreamMode.Read); // WRITE THE DATA ENCRYPTING stream.Read(data0data.Length); // CLOSE SEGMENT stream.Close(); inputStream.Close(); outputStream.Close(); } If this solve your problem please mark this question as answered by this reply. Keep coding and we keep learning. Thanks