I was thinking that may be you will be able to help for my excel document as it is very important for me lots of data will lost.

Can you suggest me a software that i can u to decrypt my excel doc.

MS-OFFCRYPTO is Microsoft’s paper specification of the encryption methods used in Office products.

The downloads on the blog are an implementation of some of the specifications using C# and are only useful to other programmers working with Microsoft’s .NET framework.

You don’t say if you are programmer.

However, it likely will not matter. You will not be able de-crypt a 2007 workbook encypted using the 2007 encryption options if you have lost or forgotten the password.

Bill

True speaking am a bit lost with MS-OFFCRYPTO is it a program or somethg that we need to modify, i dont know

Can u please help me urgently; as i have an excel doc which has been encrypted in excel 2007 n i have forgotten the password.

i hve downloaded the file liquidity.oleStorage.dll where should i use it or if better i send the file an d decrypt the password.

How do you know you decrypted the stream successfully? It could be that the call to decrypt completed without error but the resulting stream contained garbage. OOXML documents are .zip files so if the decryption is successful the first two characters of the stream you try to open should be ‘PK’. What do you see?

It could also be the package encrypted is an binary file (the Office 2007 equivalent of the 2003 file format which can’t be opened with the packaging API (because they are OLE Storage files).

If the first two bytes are not PK then check to see if the first 8 bytes are the OLE storage signature bytes.

Thanks, Joe

This comment is being added to the blog post so anyone else reading the comments will be able to see if the same solution works.

J-B’s spreadsheet was encrypted but used the ‘internal’ or default password of VelvetSweatshop. This password is used by Excel 2003 when it encrypts a document. It seems to be retained in Excel 2007 when it saves a .xls to a xlsx or .xlsm. As a result, the workbook is encrypted but a password is not required when it is opened in Excel 2007.

However this is because Excel 2007 is silently passing this password to the decryption algorithm it uses. Because Excel does it, we must also do it.

When I use the default password to decrypt J-B’s workbook it works as expected.

My file is encrypted because I’m using OLE Storage. Since I didn’t set a password on the file, there is no way to know the desencryption key to decode the file content (I try with the password of workbook protection).

Thanks a lot

If you have an encrypted file then either it was encrypted by something other than an Office product (why would my version of Office behave differently to yours) or the file is not encrypted.