SQL SERVER – Explanation of WITH ENCRYPTION clause for Stored Procedure and User Defined Functions

This article is written to answer following two questions I have received in last one week.

Questions 1) How to hide code of my Stored Procedure that no one can see it? 2) Our DBA has left the job and one of the function which retrieves important information is encrypted, how can we decrypt it and find original code?

Answers 1) Use WITH ENCRYPTION while creating Stored Procedure or User Defined Function. 2) Sorry, unfortunately there is no simple way to decrypt the code. Hard way is too hard to even attempt.

Explanations of WITH ENCRYPTION clause If SP or UDF are created WITH ENCRYPTION it is one way street and it is not possible to decrypt it using SQL Server commands. It is always advised to save a copy of the script used to create the SP or UDF on other media than SQL Server. There is no way to get the original source code once it is executed on Server. Only privileged users who can access system tables over the DAC port or directly access database files as well as can attach a debugger to the server process can retrieve the decrypted procedure from memory at runtime.

CLR SP and UDF can not be encrypted. SQL Server replication can not replicate encrypted SP or UDF.

I believe in fair programming techniques and strongly recommend against encryption. There should be no need to encrypt any code. If there is need to hide any code from certain users in that case user should be restricted using user login permissions.

Reference : Pinal Dave (https://blog.sqlauthority.com)

SQL Function, SQL Server Encryption, SQL Stored Procedure
Previous Post
SQL SERVER – Fix : Error : Server: Msg 131, Level 15, State 3, Line 1 The size () given to the type ‘varchar’ exceeds the maximum allowed for any data type (8000)
Next Post
SQL SERVER – 2005 Comparison SP_EXECUTESQL vs EXECUTE/EXEC

Related Posts

37 Comments. Leave new

  • Hi,
    I am working on SQL 2000 n 2005,Can you plz send me the major differences b/w them. And when will the cold fusion be applicable..Wat kind of scenarios

    Reply
  • Hi EvilSoul,

    Please explain what you are suggesting. I am interesting to learn.

    Regards,
    Pinal Dave ( https://blog.sqlauthority.com/ )

    Reply
  • Answers
    1) Use WITH ENCRYPTION while creating Stored Procedure or User Defined Function.
    2) Sorry, unfortunately there is no simple way to decrypt the code. Hard way is too hard to even attempt.

    ————————————————

    No2, I have a simple code for this, I’m not sure about Micro$oft Security.

    In fact, I’ve spend alot of money for this buG.

    Reply
  • Well, in my opinion. Instead of encrypt ur stored with FULL and CLEAR code, you need have a “key unlock” column, and a “indexed filter” column. Use “key column” with random algorithms on “indexed filter column” when you do criteria thing. Remember “RANDOM”.

    Problem IS: how to genarate Key Col and Indx Col? Depend your decide.

    Sorry about my bad English.

    Reply
  • Mike Dimmick
    May 29, 2008 6:25 pm

    In fact, due to a flaw in how SQL Server encrypts an altered procedure, decrypting the original procedure text is easy.

    SQL Server uses the RC4 cipher algorithm to encrypt the procedure text. This algorithm generates a stream of key data (called the keystream) from a starting key, then encrypts the plaintext by using the XOR operation. The beauty of the XOR operation is that to reverse it, you simply XOR the ciphertext with the keystream.

    Unfortunately, when you use ALTER PROCEDURE, SQL Server encrypts the new text using the same key as it did when encrypting the original text. This means it uses the same keystream. To recover the keystream when you know the ciphertext and the plaintext, you can simply XOR the ciphertext and plaintext together. You can then recover the original plaintext by XORing the recovered keystream with the original ciphertext.

    You can find copies of scripts that do this in numerous places, for example at .

    I’m not sure how SQL Server decides what the encryption key should be – it may be as simple as deriving a key from the procedure’s objectid.

    SQL Server 2005’s documentation describes the result as ‘obfuscated text’ rather than ‘encrypted’.

    Reply
  • Hello,

    There is a tool which can decrypt the encrypted stored procedure. Is there any way with which we can restrict decryption of stored procedures? In my situation the database would be in the client side and I would like to enrypt the Stored procedure. Please help.

    Thanks,
    Abhilash

    Reply
  • Hi,

    Is there anyway of encrypting more than 10 stored procedures at a time?????

    Please suggest…….

    Thanks in Advance

    Reply
  • Hi Vinay,

    Yes, Use the code provided above (copyright prevents redistribution so you’ll need to sign up and download the code yourself):

    .

    and wrap this up in a cursor or loop. You can even call this using xp_cmdshell ‘SQLCMD…’ via a batch file if you wanted to pass in other params (multiple db’s, serverinstance, etc).

    All the best,

    Matt.

    Reply
  • Hai
    can anyone tell me how to create a stored procedure with an encryption and password to decrypt it back again when ever requrired.

    Reply
  • Hai
    can anyone tell me how to create a stored procedure with an encryption and password to decrypt it back again when ever requrired.

    Reply
  • how to protect table from viewing its data and columns in sql server 2005, we can encrypt SP’s and UDF, what abt table, i read an article on this but its for data encryption in table, but i want to encrypt table columns itself, i want to restrict the user from seeing its design

    Reply
    • Hi Giri,

      Did you get any solution for encrypting table structures (not table data)? Please forward me here.

      Thanks in Advance.

      Reply
  • please tel me how to hide the created storde procedurs from user

    Reply
  • Hello Krishna,

    In user database set the user’s property to remove the View Definition permision on selected or all stored procedures. You can also remove the Execute permission on stored procedures. For this go to database > Security > Users > right click a user > Properties > Securables > here add object and set the permissions on that object.

    Regards,
    Pinal Dave

    Reply
  • Hi,
    How do we encrypt multiple stored procedures in one go? (Surely, keeping source copy in another database )

    Reply
  • Hi Pinal,

    Only privileged users who can access system tables over the DAC port or directly access database files as well as can attach a debugger to the server process can retrieve the decrypted procedure from memory at runtime.

    Is that mean administrator can view the decrypted procedure? Is there any way to hide or prevent from retrieving the decryted script from the administrator?

    I also read on some articles that there are some softwares to decrypt the encrypted SQL scripts. Can we prevent such softwares from decrypting the encrypted SQL scripts?

    Reply
  • Hi Pinal Dave,
    If i create one encrypted SP then please tale me how to give permission to selected login user like sa or other user which i created

    Reply
  • Hi Pinal Dave,
    I understand the risk of Encrypting the sp’s, but As i am experiencing the security risk of my database as it can be easily copied to other system and get attached to another instance, I feel need of encryption. Even creating the user won’t help in these conditions.
    Though i am new to MS SQL, I strongly fee that MS should incorporate the user specific database files for strong security of the database.

    Reply
  • how can i decrypt view in sql server 2008

    Reply
  • Hello guys,
    We strongly recommend NOT to use WITH ENCRYPTION option, because as easy to encrypt, as easy to decrypt. Unfortunatelly, SQL Server uses database’s GUID and object’s ID as a key for deprecated RC4, and then simple byte-wise XOR. We hope Microsoft SQL Server’s team will eliminate this flaw or just desist support this option. As a solution we provide our FREEWARE named SQL Decryptor. Check it out on our web-site.

    Reply
  • Narendra Thakur, Karsog, Himachal Pradesh
    October 23, 2010 12:38 pm

    Dear Sir,

    I have my StoredProcedure encrypted using “WITH ENCRYPTION”.
    Now how can I make changes in this stored procedure.

    Reply Soon!!!

    Regards,

    NarendraThakur

    Reply

Leave a Reply