PKCS7 padding in .Net vs PKCS5 padding in Java

Question

I have scenario where my existing encryption that is written .Net (C#) is not getting decrypting by Java service (using RSACryptoServiceProvider). The issue identified is that .Net environment support PKCS7 padding but java expecting PkCS5 format.

Can someone please explain me how to make sure .Net RSACryptoServiceProvider encryption with PKCS7 is able to decrypt in Java. Do i need to change my .Net implementation?

Answer 1

You've posted in the wpf forum.

This is a c# question since there is no wpf technology involvement.

c# is over here:

https://social.msdn.microsoft.com/Forums/vstudio/en-US/home?forum=csharpgeneral

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Hope that helps.

Technet articles: WPF: MVVM Step 1; All my Technet Articles

Answer 2

Hi TechoNeto,

The difference between the PKCS#5 and PKCS#7 padding mechanisms is the block size; PKCS#5 padding is defined for 8-byte block sizes, PKCS#7 padding would work for any block size from 1 to 255 bytes. So fundamentally PKCS#5 padding is a subset of PKCS#7 padding for 8 byte block sizes.

so, data encrypted with PKCS#5 is able to decrypt with PKCS#7, but data encrypted with PKCS#7 may not be able to decrypt with PKCS#5.

Best Regards,
Jerry

Answer 3

Is it True?