What is the difference between Aes and AesManaged

Question

I found two class in C# related to AES, and example code of them MSDN provides are similar, what is the difference between these two classes?

Aes Class

https://msdn.microsoft.com/en-us/library/system.security.cryptography.aes(v=vs.110).aspx

AesManaged Class

https://msdn.microsoft.com/en-us/library/system.security.cryptography.aesmanaged(v=vs.110).aspx

Answer 1

System.Security.Cryptography.Aes is an abstract class, representing merely the concept of AES-ness. AesManaged, AesCryptoServiceProvider, and AesCng are concrete implementations of AES in managed code, using Windows CAPI, and using Windows CNG (respectively). (On .NET Core that's a lie: AesManaged and AesCryptoServiceProvider both just use a automagic hidden class which uses Windows CNG, macOS Security.framework, or OpenSSL, as available)

If you're unclear on which one you want, you want to create an instance via Aes.Create() and only use the base type. The only real exception is when using AesCng with a named key (which is very rare).