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RC4- Microsoft Enhanced Cryptographic Provider 1.0 128-bit


We have a client who was previously receiving Excel statements encrypted by another application using “RC4,
Microsoft Enhanced Cryptographic Provider 1.0 128-bit encryption.” They have an automated process which decrypts the file expecting this algorithm.

We are now using Apose.Cells to encrypt the files using the following call:

workbook.setEncryptionOption(EncryptionType.STONG_CRYPTOGRAPHIC_PROVIDER, 128);

It appears that this uses (RC4,Microsoft Strong Cryptographic Provider), and this is only encryption option available.

Question: Is “RC4, Microsoft Enhanced Cryptographic Provider 1.0 128-bit” encryption supported in Aspose.Cells?


Based on this following article. I can say, Aspose.Cells for Java supports the encryption with the desired algorithm for xls files.

Setting Strong Encryption Type

Below is a code to open any password protected file. I have tested it, it works with xls files but not xlsx files. It seems encryption is not supported for xlsx files. I have attached the sample xls file and the you can see the output below. The password is 007.


String filePath = “F:\Shak-Data-RW\Downloads\source.xls”;

LoadOptions opts =new LoadOptions();


Workbook workbook = new Workbook(filePath, opts);

Worksheet worksheet = workbook.getWorksheets().get(0);

Cell cell = worksheet.getCells().get(“A1”);




Please read my post again carefully. The article mentions only

RC4,Microsoft Strong Cryptographic Provider

What I am interested in is

RC4, Microsoft Enhanced Cryptographic Provider

Can you please tell me if this is supported, and if so, how to select it? I see that EncryptionType class seems to only support
Strong , as mentioned in the article.


Will you please provide me your sample file so that I could check it if it is supported.


I don’t believe you need a sample file. Please take any xls file (93-2007) and try and encrypt it using RC4 Microsoft Enhanced Cryptographic Provider algorithm. It this is possible, please provide me with the API to use.



Yes, it is supported as I found, Aspose.Cells for Java was able to open it. I am attaching the source xls file which ran successful with the above code.

I am not trying to decrypt/open the file using Aspose.

I am trying to encrypt it using it RC4, Microsoft Enhanced Cryptographic Provider 1.0 128-bit.

Can you please show me how to do the following using Aspose API:

1. Take a sample unprotected XLS like your source1.xls
2. Show me the Aspose API used to encrypt this file using: RC4, Microsoft Enhanced Cryptographic Provider 1.0 128-bit.
3. Check in Excel that in fact the cryptographic provider used to encrypt the file is
RC4, Microsoft Enhanced Cryptographic Provider 1.0 128-bit.



I am afraid, this feature is not available. So I have added a new feature request for this issue in our database.

Once, we will get some update regarding it, we will let you know asap.

This issue has been logged as CELLSJAVA-31192.

The issues you have found earlier (filed as 31192) have been fixed in this update.

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