Rijndael.Create in Main

Why do you create Rijndael in Main? I think we do not need an instance of Rijndael to pass a key and a IV to the EncryptStringToBytes and DecryptStringFromBytes because these methods create own Rijndael's instances.

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#### Document Details

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* ID: f75dbabb-9969-e85c-1195-153fb2b6fe92
* Version Independent ID: 4c73e392-1752-fc6a-75fd-36f005e92bd6
* Content: [Rijndael Class (System.Security.Cryptography)](https://docs.microsoft.com/en-us/dotnet/api/system.security.cryptography.rijndael?view=netframework-4.7.2)
* Content Source: [xml/System.Security.Cryptography/Rijndael.xml](https://github.com/dotnet/dotnet-api-docs/blob/master/xml/System.Security.Cryptography/Rijndael.xml)
* Product: **dotnet-api**
* GitHub Login: @mairaw
* Microsoft Alias: **mairaw**