SPMS_API/SPMS.Infrastructure/Security/AesEncryption.cs

using System.Security.Cryptography;

namespace SPMS.Infrastructure.Security;

public static class AesEncryption
{
    public static byte[] Encrypt(byte[] plaintext, byte[] key, byte[] iv)
    {
        using var aes = Aes.Create();
        aes.Key = key;
        aes.IV = iv;
        aes.Mode = CipherMode.CBC;
        aes.Padding = PaddingMode.PKCS7;

        using var encryptor = aes.CreateEncryptor();
        return encryptor.TransformFinalBlock(plaintext, 0, plaintext.Length);
    }

    public static byte[] Decrypt(byte[] ciphertext, byte[] key, byte[] iv)
    {
        using var aes = Aes.Create();
        aes.Key = key;
        aes.IV = iv;
        aes.Mode = CipherMode.CBC;
        aes.Padding = PaddingMode.PKCS7;

        using var decryptor = aes.CreateDecryptor();
        return decryptor.TransformFinalBlock(ciphertext, 0, ciphertext.Length);
    }

    public static byte[] GenerateKey()
    {
        var key = new byte[32];
        RandomNumberGenerator.Fill(key);
        return key;
    }

    public static byte[] GenerateIv()
    {
        var iv = new byte[16];
        RandomNumberGenerator.Fill(iv);
        return iv;
    }
}