altCrypt
A highly flexible symmetric file encryption/decryption library for .NET. No messing around with streams - this library does that for you! (but you're welcome to continue using them too).
The library can be used in your own applications. Or you can use the command line utility to encrypt your files and directories manually.
Sample Usage
IFile file = new LocalFile(@"C:\temp\MyFile.txt"); //1. Select a file to be encrypted
IKey key = new Key("Pass@w0rd1"); //2. Create a key
IIV iv = new RandomIV(); //3. Choose how you want an IV / nonce to be generated per file
using(SymmetricAlgorithm algorithm = Aes.Create()){ //4. Choose the algorithm you would like to use
var encryptor = new FileEncryptor(key, iv, algorithm); //5. Create the encryptor
await encryptor.EncryptAsync(file); //6. Encrypt the file
await encryptor.DecryptAsync(file); //7. Decrypt the file
}