specified padding mode is not valid for this algorithm

[Itsathere]

I have a project in vb.net framework version 4.5. I am upgrading my project to ASP.Net Core 1.1 and trying to decry-pt the same encrypted code of framework 4.5 in ASP.Net Core and getting exception

"specified padding mode is not valid for this algorithm"
I have used the Rijndael algorithm for encryption/decryption of data in Asp.Net Framework 4.5 and still using Rijndael in ASP.Net Core for encryption/decryption but getting issue.

Can anyone help me to find-out the reason behind this issue.

Thanks

[JasonPierce]

@Itsathere are you using this lib, Rijndael256, when experiencing this error during encryption, or a different implementation of the Rijndael algorithm (e.g., System.Security.Cryptography)?

[Itsathere]

Yes