Producing an AES Cipher To Match OpenSSL in C#

I received a strange question over the weekend:

“Why is my code always producing the same cipher, no matter the passphrase and salt?” I use C#, and it is not producing the same output as OpenSSL.

Well, the solution was clear. It is all about how OpenSSL does its formating and key generation. The ciphertext was actually changing, but the first part of it was…