Hello, thank you for an answer. Sorry, maybe I did not make myself clear. I mean that for uwp this code with Rebex.Legacy.Cryptography works fine, but my point is to transport ecrypted byte array to the web api and decrypt it there. I'm using same code in web api, but instead of Rebex.Legacy.Cryptography i'm using System.Security.Cryptography, because , it is not possible to use Rebex.Legacy.Cryptography in web api. I proceeded from the fact that Rebex.Legacy.Cryptography it is wrapping above the Windows.Security.Cryptography and should have the same logic as System.Security.Cryptography. Is it possible at all to use such approach? If no, please, could you suggest me solution. Thank you.