无法解密MS日历事件信息的丰富通知？

Question

我创建了一个订阅来接收有关创建和修改日历事件的通知。问题是，当我解密通知中的详细信息（例如标题、开始日期和结束日期）时，特定长度的初始部分无法正确解密。

Decrypted data: x�������p��\ud14c\uc2a4\ud2b8123","start":{"@odata.type":"#microsoft.graph.dateTimeTimeZone","dateTime":"2024-03-27T03:00:00.0000000Z","timeZone":"tzone://Microsoft/Utc"},"end":{"@odata.type":"#microsoft.graph.dateTimeTimeZone","dateTime":"2024-03-27T03:30:00.0000000Z","timeZone":"tzone://Microsoft/Utc"},"organizer":{"@odata.type":"#microsoft.graph.recipient","emailAddress":{"@odata.type":"#microsoft.graph.emailAddress","name":"\uad00\ub9ac\uc790","address":"[email protected]"}}

我的解密代码是：

DirectoryInfo currentDirectory = new DirectoryInfo(System.IO.Directory.GetCurrentDirectory());

var pfxCertificateFile = currentDirectory.GetFiles("*.pfx").First();

X509Certificate2 certificate = new X509Certificate2(pfxCertificateFile.Name, {MYPW}, X509KeyStorageFlags.MachineKeySet);

var privateKey = certificate.GetRSAPrivateKey();

byte[] encryptedSymmetricKey = Convert.FromBase64String(encryptedKey);  

var decryptedSymmetricKey = privateKey.Decrypt(encryptedSymmetricKey, RSAEncryptionPadding.OaepSHA1);

byte[] encryptedPayload = Convert.FromBase64String(encryptedData);

string decryptedResourceData = null;

using (HMACSHA256 hmac = new HMACSHA256(decryptedSymmetricKey))
{
    byte[] actualSignature = hmac.ComputeHash(encryptedPayload);
    byte[] expectedSignature = Convert.FromBase64String(dataSignature);

    if (actualSignature.SequenceEqual(expectedSignature))
    {
        AesCryptoServiceProvider aesProvider = new AesCryptoServiceProvider
        {
            Key = decryptedSymmetricKey,
            Padding = PaddingMode.PKCS7,
            Mode = CipherMode.CBC
        };

        aesProvider.IV = new byte[16];

        Array.Copy(decryptedSymmetricKey, aesProvider.IV, aesProvider.IV.Length);

        using (var decryptor = aesProvider.CreateDecryptor())
        using (MemoryStream msDecrypt = new MemoryStream(encryptedPayload))
        using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
        {
            using (var ms = new MemoryStream())
            {
                csDecrypt.CopyTo(ms);

                byte[] decryptedbytes = ms.ToArray();

                string base64decrypteddata = Convert.ToBase64String(decryptedbytes);

                _logger.LogInformation($"decrypted raw data (base64): {base64decrypteddata}");

                ms.Seek(0, SeekOrigin.Begin);

                using (StreamReader srdecrypt = new StreamReader(ms))
                {
                    decryptedResourceData = srdecrypt.ReadToEnd();
                }
            }
        }
    }
}

我使用如下选项进行了订阅。

DirectoryInfo currentDirectory = new DirectoryInfo(System.IO.Directory.GetCurrentDirectory());

var pfxCertificateFile = currentDirectory.GetFiles("*.pfx").First();

X509Certificate2 certificate = new X509Certificate2(pfxCertificateFile.Name, {MYPW}, X509KeyStorageFlags.MachineKeySet);

string publicKeyBase64 = Convert.ToBase64String(certificate.RawData);

var subscription = new Subscription
{
    ChangeType = "created,updated",
    NotificationUrl = "https://example.com/CalanderSync/notifications",
    Resource = $"users/{userId}/events?$select=subject,start,end,organizer",
    ExpirationDateTime = DateTimeOffset.UtcNow.AddHours(8),
    ClientState = Guid.NewGuid().ToString(),
    IncludeResourceData = true,
    EncryptionCertificate = publicKeyBase64,
    EncryptionCertificateId = "{CERTIDOFAPP}"
};

我改变了paddingmode，但是没有用。我找不到这个问题的原因。

我希望解密的数据以

开头

{ "subject": "test 

不是

x�������p��

解密数据：

x�������p��*\ud14c\uc2a4\ud2b8123","start":`{"@odata.type":"#microsoft.graph.dateTimeTimeZone","dateTime":"2024-03-27T03:00:00.0000000Z","timeZone":"tzone://Microsoft/Utc"},"end":{"@odata.type":"#microsoft.graph.dateTimeTimeZone","dateTime":"2024-03-27T03:30:00.0000000Z","timeZone":"tzone://Microsoft/Utc"},"organizer":{"@odata.type":"#microsoft.graph.recipient","emailAddress":{"@odata.type":"#microsoft.graph.emailAddress","name":"\uad00\ub9ac\uc790","address":"[email protected]"}}`

Answer 1

Graph SDK 支持在 https://github.com/microsoftgraph/msgraph-sdk-dotnet-core/blob/dev/src/Microsoft.Graph.Core/Extensions/IDecryptableContentExtensions.cs

中解密通知

您可以提取并测试该代码，并使用他们编写的单元测试代码来比较您使用的内容，例如

// See https://aka.ms/new-console-template for more information
using System.Data;
using System.Security;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using static System.Runtime.InteropServices.JavaScript.JSType;

var certificateString = "MIIQagIBAzCCEDAGCSqGSIb3DQEHAaCCECEEghAdMIIQGTCCBg8GCSqGSIb3DQEHBqCCBgAwggX8AgEAMIIF9QYJKoZIhvcNAQcBMBwGCiqGSIb3DQEMAQYwDgQIEAk4/VMAFtsCAggAgIIFyAXxkPPBcl1MbwgA3SSTHD3WBxi" +
                        "qiGVC9+0ufNW70SoIyx7V9ZVP/eFXb/moZD7BEir30WCdqqZCvh3aHvoL1SlreKXFmYqLzUViqBsHl3GIox2f/Ic7CS486JCoLHMoTHPcC3Y40zr8HX+Zc0SJs1cT4KFN3UJnoKwD+lWgn7XOiyzKWC6zksqM2spnc5W6+I5eHo" +
                        "SDEkgPa6mDYtB+0/9bPSV8XkDu9MWGUhq+bNBlenMwAF+QeWBbaTskiEHgloJPzqVop8aT/KRsKLNBrWQ64JJ5dYG/yjqg0/oA//T8/cCDqhTuc0FiS4IRzmKnTsOuVgbwJ8t3vvd6lHRfFZXTYnMmRLuZ62xvzsAIRCg6+CUmU" +
                        "fJB9SZodYMD1dC3ScIHoNbbgJUfbUOriC9lL6kLPdxBOAmICMy+47t1PvmFpFJe0fzz8M26Lg5Bbc+pVdwKBDXa2+15Dw/vSiTZuEq1e5C/EJwZDzKU9cskqONGeegxSMDlY12vJR2eY6m/fVrpu58QTAi9kkl5+U4naQp4WXMy" +
                        "9EydbqNWge1Y3CFxZBldktC6PajhjAF83mMaohAZ+91SfTLx2bar8vxWxCTePSwci2vyZDrzSCvogaNa4CMJViz7Vfbzof4WOTw5tYin9cCNHQuw47hLDVZtIevavAkwruwmXNbd1l7lr9433AdBRh9iiG6uMpwJYAPwj8lkGDU" +
                        "1H0MFBYjvWMVdh3S4KUkN6kIZPCryFcBKWvqmZn0tVpCbtIlCARXEoz2iYR+VydRW0C5+BlnYCCL60rylirKlRQSm4yzY6vr3wFjWxtEn4SMdR8HUhT7EqAel6AIYO9ZFsJ76GK994l/QMy++pjd4HRIw3SSNoshzQA+y9+MWcP" +
                        "sUMUj0gS+9NXr/GZ/G4m1gWnuFOnulUWXYD1CctimampvaPwdcWKrUKnzUeMFYxMkMdycEkfePPw4oTYHw5/OgBv4/3PNuuIDBwA0XNop9ixrcNtT+O2eqyITIJLZ6xcxS8aVvrGeGcKs+u0CC4mqvKKVXPLYJ7qN1lznHVEMB7" +
                        "97JM3SQyhGcYXOqDRV4GlXbAPYbH7P7pbepTF/Y2TascDkcpmX3UeglK6L/zcNG2X+RdjVrJpeNCYVHt9xgQ2eIb9O+6U5eBt25UeUjqa1JBcHf1/XcMIp5+Tf0xO00xV+faI9vXFk5C3DuEOQh6E7Gmp+aPa/s9H/4yV2teuYJ" +
                        "SxXkszbTvy5bC0C00rD9qFsQORNnZM1MePzbQ0CNAadNiDzdOluDRruwKAGWtxjnjqzMOxfRBZwx2AJfc7EO2zgUaUpoCQQ+Aznnt1zHoWsTP1HcloE3MginzLi76PwwEMbvnc6U2stqsbkENqX6O1OahqeP9C98qlXt12j8vmV" +
                        "xbFbLRFJYEDkv3hEIOkZmfIUZZ7PtQG6pcz4MXy8VNubgrz1BKd1FDiajGEN9w0z18sszjVRogiTIuST47eN473PmeqMuQDKf4w+nFsQbPYC7Ldxd+DHCdDVXpEeF3ImtmB5cvZnL8VSnCit8Uarws9tj8NCL0RaCJa5aAWGdkb" +
                        "9+Se4A1sBLn60lODQ0VLGg6M3GQYlLKkGFDNZ13SfBlEzehOE3yIPo+BD2kFoR0Tp1ITMj5CX88EZ30CY1u0vDtjHlFnvCcUcCxA5Ck8QaVR+3ghdUCFyZWjc7pd6ivRnH1AUO3f3HJq+UYbBHvKEG6UYviPGypijsH+4utOdxU" +
                        "sLCp7Xo06ieotorfbTLMkLcp6G0PykLbT7D+B5f+XNfB5pvjIzB5qo7b9tq4KzVVm67aBCRWF9UQP59/XbHpTL8UCHPB5StAkZNSfaqFIetiJFbYhRK40G5eOiUShX3SZnwxejRb91TrR4in3HuiB8VvAxxzozqJrFBT02XiNuG" +
                        "3EzW215isLunbU7o3w2ZVrspwWDNJV1kWv0gtg4rls+vt/jSQ+lhwGiZHHVw7WPlnzMwggoCBgkqhkiG9w0BBwGgggnzBIIJ7zCCCeswggnnBgsqhkiG9w0BDAoBAqCCCW4wgglqMBwGCiqGSIb3DQEMAQMwDgQIAE5+HZYwEY8" +
                        "CAggABIIJSEPsDMNEgZJkFSZUJZ8cuCA1E2e9/jJUu3RPzhoUMRjx++17zprL5LVF4vfQ2Dgd16pQ/IdP2yhK+YHfWvjYvo9E/xPx2V6qXzC7r1VyO0qZSmYuYhVIlMo+vrexuT0UeWQvjXX72DLVcixCGWrUf8qt9CqofChyjn" +
                        "UddsD9hdoWgNSTgBMi6aNFxlFFfeJMOeTfUbFOGAnUFwySWUnwA3Lx7NrcKWLngmvmyo/zl8++M528SeEGAT7jeZ3NdkI8OqCWlE77ybmZYHXJRgq4D01oVdiQAgnd3Wj8sKmrjIByc23IdIrusHgM5b9BYXdsiEo3seJ6H4V4B" +
                        "tG5KOPFpM3m2KwZDtlLfgj4Od/XbyZwtRkLOVvOA8ARtDPlfIR8nW+ptFpMlaWGX72oreMm6utQ3OWJtjx+xFKm+VgVhJpJrt1NC1U1vnVp3apwcSXB66nf6gxfipQoUubUoFqUbIBA6lVECVN2XQcO9oHF4exOxAXA0/R45dMm" +
                        "UIRAc81x6B5I/sRWxYybwtWDUvilLdpjmgzjrQZM8S7EiG13r8mRbYXgtAHFxDv80DYZuywutclEYrFEVoXLGmXBXqlw/uFRQq9ee9xFbrYet8nYCIsUhPc5xF3bLG5bNaIhNrey3+53PlX6ralAfDmCFUHFor2pVnMP0HxG7bq" +
                        "8ylUNzIVbcliDFIeukdF0fBc0L7VtGaXKLKSZPx7QE4W3dzGRkBPTuG13wOf7batwdV5AwBUoNXLKqbvzqj/M6LgCTdtZ0Qlf7MKH1Av2aYxIV9m/053CKL3tmCj06EkuTWhmMQcfckrnMoInVrmgOpsjX0nQ1EaxkglJtpm2u0" +
                        "MKN7f9liXOzg5x1aUvIIEddJUxTnpbcl8AEGnPuZvScsQ9JajbRA8v+0gv+qLIgh4esC+AV4ufRV01HOjA/30S1WTAykU+HPvLq/goz8SwtLVmD9F1n5ppWULLYbQObKVUmGiJWjvFDdVtuR4XA1SpBO6nC4wL/Qe2CG360uj9s" +
                        "zvgDXYVF108/Xr/pJqwHhyb3dujsPre73zS2AWjKPRC/qbe+LZw+Yj4KVD3MslFg14CkS/TPK1zdUyBEnNJIBatbp28/NNX3bMd2TaB7mIlr4T2iSQI4yf5U5gxnPXGOUeqLqKbi7iUbHHk6407PkyIZPyBxUaSIi/KtpUkGvY+" +
                        "aTAtLLA5F6tKp6FpsvbGBUkOCBcAMLc36Se9GG6UfBf6ZIFtZBpugp4+aZlKxzzigEF+8S4v4/4lm4HcLE7dC8ChD+fPtAQqqMjWmJnrp1Jm20URW//8mk7WVzNTEPuRIeFXTLw52pRtO6E51V085lX3cvEvNgcN3GiCnztb5W7" +
                        "Tx5eYFGbkXKhmc8OSbNZ1QfAlWwPyVumFujC7bLiCp6V9R0MMUlGY6BiJwFNGM0Isoz7v3Y2DLlYdztdNto9I1+73mMXsCnsCmQTE4pqjGX4imva64pIELuQ2AE2ecAZ7/J/v3DXhsgUXkAnjZIvqnAr/UOBkDDjLc7xByGEkzD" +
                        "D0PFQclF4ehxo8s8ttUT9VXmLuWgj1inbIU7gcTWaVZFA+4cTeuKDfOCQ+LNaYrv3EZ96FuEO/Dj0Eo+7iiIvWm13ggN+39Bmbp+nerB2r0geAOO6QiPIRD8v2Slwv2Pv3CrBhSX9mVAFt195ZFd3sojhGgqlcJ4tRdV/pGb5At" +
                        "4T4D0qcRop3aOQ9UST5e1Gmc2w3+z07tCEBsp+teQurAVjX7laEHhA2oavJii9DGAau94X63lURBEQmX8EE6b/9k432dTw5evCkzzO3XMyssvXuEHeuSPnFnLkHFrn9IuHh9LkZvTkQbXRuVVhjnmrfy8Hgq9hK/Tgfax0vow8G" +
                        "v3CVPptYxL6uo+N4aHHROU4IkOiaV8hUIRFeKh6uE8ILDxWKo+QT5i1iwsm6mhm4cZno7NxCseIXmveU47qhJ/FuwMRVzUfvIzeanEoNUUEEyurqgDSJWqtZLHa9N2FbHHbR30YF7HekH48mvB7MXcHywHEcgMo8rL4I1F820Bd" +
                        "tLL4xXc1g0NoFWpnrBavoi6mCNcqc4eULIcF5MPg9k1xE663Sw6xlrVKEgXDHHivsv4Y0D5EYRxcqeOkkQ4AwH0a7Y7ps2ZsUxVenXtBqSeaGgY5tY4GX55+ko9tyyOkVV9XT6JcBfCxPtwEeyV+oVlMRg9alVCiw7scMeFFDiH" +
                        "+4a6CI/J0hyluBjuChypu6i1UjJDC+GloiyiiRktBw1b7Hytg5w8u9tTMNCVNHWLuvGSmzPyYymAIiRSqrCtVH/APv+SWtGC+eNh5+mZc0hz7hHi6gmc7zB/58+VVOdm0vqGaQx28uv5Pht5yw7KgKgtFt//0KvAsCKYso6FsTU" +
                        "4IzJL3uBPp20xb5Vka4I69c3ysd8Jcx2Y3fykech34fhRLIqJRBo42+ekhAEkF5nZTVFBYgOFv6jir4gTxI4Bax6ukBNDQYDY9VL+dIDU1/PPtepHRNB6lqlKX4Y5T6tqn8u5UbeMVug+ket0oaQ4SObAOkrJdgyE1aGXfSYGoD" +
                        "vOYz8OCFWNJjDECCrZgniKbV+fxgcOExbXD1Au9W0wgHnagT+uoik0rshi6nsIel4XmVv/MiQowK35s6Olq4mrdRPoOwoePuo3/CEL+BwRlX0aJhFgRS5O0L/zD8Hc8EPR6CO9+8jbkbBQ80KnVsS25ArgoA45CSFCrmqRxFnnp" +
                        "R6Dvlr0EmlDfGOnFlnZXZNIuPYZZT6UbH0ObaxDKYMPZ2NRbfETfdDHM+WBPuqGVc6OiMqa7PFkHjispf7saXtSrcpL+UYvNzX4PQwpUi8frl0Aq7w7c8GKosmaNp3VYiTc9cAcd/JlX5dAZK2yndVpmQlUeA028j5Lyc9Hm9Gn" +
                        "T6wjPT4x2lYvXd+AwOBY/3CY2eAslCN+4nmoRZnovDH4Ffp2bnId9FrsViBDWLKWV63yN2OTnTPJxj7ZQEC6T78sdqEpw5vKdi3xYYj2MhBXNohE0lK3Ig4ijsB9P16bXA8PcKaIwhnpeTKsLcdBPwVapuDku24u4u/Z/A+Q3Ls" +
                        "lbEJdiRhGrHv6I+MJd2Gx/1qBU6VO4N/vC/VL3uv5VY/zRcA4r4ff7m7nfsuwyz5JsLMIcQEx0LuKyy74XmayhpdDE1RlovO0+JkzFmMCMGCSqGSIb3DQEJFTEWBBRLlTU+CGrTcZZgas+DShRTLwPm2zA/BgkqhkiG9w0BCRQx" +
                        "Mh4wAHIAaQBjAGgAbgBvAHQAaQBmAGkAYwBhAHQAaQBvAG4AcwBhAHAAcAAuAGMAbwBtMDEwITAJBgUrDgMCGgUABBShhhfLZmAOmqGltImT+9krDrQGAgQId7jD11L05jECAggA";
var secureString = new SecureString();
secureString.AppendChar('r');
secureString.AppendChar('i');
secureString.AppendChar('c');
secureString.AppendChar('h');

var data = "FFYlP1Bgb/fWW2kHMZiq4Y98E+XL0QTWEnGogTF6RRS+i3KqlXw35yy5ax8fEOzJbLc10ky24Ij+5ei2Hwqkzhph35XdLIsVsJZlQNYBwOu4jKvYbbhc1uHpQ/QBbs" +
                      "4IcdtWKCojqnDYcJmhwkzOZYHUr6XFHHD0GbO3y/wE0BKxMG6d5gNMfbT08OSWl+bhETeGVif8GTgZ0CNA6j7Xlq2T9Jd512cEBtEbXgJoISJVyOo4YzSirrb4R9xr" +
                      "lw9ASdz+oEzKZeUh0NSKfihjvevg90f7r5ZCHH1bP13Fxi/9NxASS7Sv28kvQbl+bqjNvCXK/Ol7rQr4DfMXPG82BGYU8n5AmWBztTY4mZLR59896coFz4CCDai4aS" +
                      "WDO1ldldvW9eqsnWTukQSwef3nHMMwTNxGge5YRMFKfVjOKr55xI7bevi2pZ6iZm8Kp8F+Gi+5V1uDpUFqeeFG3z03e7TfqczNIHdIjqxFpdYlrh/7ySd3L3q4D3TT" +
                      "vVCRdrbjuJ4oZeuFG4PQbAmJBcMwLrWDBmAykTRtrMT1Y1Ur1lX6lTiikGkrlV1VPizykLZmkq6jeoJOnMVLDWpNlQSKKfDicHRWoBHxDHc/g0aPs1g9Jd0I06YsVi" +
                      "JsEhvRz5Kwp4jAbyDff1XVExYPKRA07EfbOl5dLReE6ATcJGBr1dI4VVECRS7yW+uYTxoUUyePUOGIPGgpCBzJGYoRXKpBibcRib4Xs6WHVrEwNkN2RTHneh7NdzUm" +
                      "Piv5RoTSBFKRgysb5pWt1aUwIOnvjxLPIvTJmOob6nYvR/qCkfczEDzofYjG8H/7m2n/tqVvrs73QH7bIgapSU6GMhg41+Sizkjo4NRaIg2xrn7KM9NRJpjhsw5IyP" +
                      "Df2VgJlO9CruoCOHnbSlXCMeQUXATmXc7+bp4Zg18D2IXDryHhmc5GaBgrhzKjZtfvFzkLjY57VXODrsUB5Erya39RaX5bkqDXgzxHR3LWXZPlfuXCPKG5sPc1fGcP" +
                      "nS3+xONICej5xGxzdEo/t9esmGPWCSv3EyxBY+r7PIsNQ2gzwE5WERiRE83NHXrM1sYoSg83NqL5yZ/ohhR8lU3MTJ4xypnAglh+UdYIwqKaO4LKXaSO1Wg2MXWFAH" +
                      "BNVAYY64OrxUwm4kUS5T8CPypGKm5qHWJsWZ2dryGTwEoAKfVM5kWfhQ+56jpwN0AxCtgvGBvt7FX0S5UFa9rMf3EYgsXDQLw+o6N6W9LRC+nmQX+HTyl1mgHf/aGx" +
                      "8EW3DH3Ho52WgBf5IJ/TsvhLpDF6SKZrKLa1qm9PzShR0CGkLl+39pOT9bvcYhVW9I/mI6qv/84ben4NC0nDV31DdGTlB/pY7pIpmQuqSUQi+QAOQqO6oAYP5hh8Ey" +
                      "SQWapIyGdLE3R5HXEQJNVRYZM3BFlQ68HdPOi45KOp3PUAll3GNyxvjzE4UfeSTNGLMEll4Q2V3DlP1JcfIQNBi2SrVPtdq2A7l5NjyPoLnxKF8aoDWfunp0dAJcl" +
                      "eZNecO1YSXliGeisSiuumCTBKoLlx18XUZ4lfimtFChOnqC80RoVGSMTkM4anng99IHLUp/cOwRvnPmThGeTJX294ZsGlxrjmS3p/6DACHZKzy15GHYwhioMUDmcmX" +
                      "VYC2EkN/QPFd/nGUi6KM/dMpJ3mqXxyqP+F4d4b+Dv64QBijF5OFUffc9c46r5aoh0enIdY3TmC/hFloCQlHcrU83LBO2880TKnJI5xPbjjtZZxjA==";


var dataKey = "PfUrKAM9G3k7Bx3XUAQ7jJwvceKrJwO7immbL6c+cFU2RCRicRAAA35C5c2iuEItNxQoXEHBei9aalToPg6XaOVqU7Y2U0vYZ/OPJ9+7gXRk4zYdLTWQgZMeXaa" +
          "NgJIE0xc8BCuYKacT/iB6aY9JHmj2rbR6EDbMTKWkVBe+Z/qtQFhJFq9WBLXsh719qLl/MQarYCDrTNQtryF0WXn0UuLh2OIJYV9T8eSv4j1ZM0WDKw0X9MLaqF" +
          "PZsZ0SXX4t2EArdnrCBf5duPPCcmfhnvrimqiynSJPDQT0e63oLlpW1z37TvZTeyORY1YTQRmaKWD91fiYtuVmSSVVy2vg+Fm7UIG082bc8y7LT241Qd5RosJaf" +
          "1w+JPZbttjm7I6uT22XOzaNRouQWx5UxRvWllm46F3pFNq0dn0lztdsW0QckAV4M86wwObVZbqUbnDZ8YloHz0XRRg7cU0H1K60fPMAo7PUoMV+bJC9HzB5O8jp" +
          "TScDd4yOYZPB1liV2PHRHuIB23lVUARe3MuMo4i+hAc/ftK9s7yvREBuBSD0wi9R6qCygZ09YwrqfXZjRlKcFnz6EE7sqT1tzs4OxdT8XgAdveV6PU968kQhema" +
          "TsSSrmpvsVn46mMb1le2YY5PUukxZoUFiDMZb036C56HAQ2cyWZkNweDxDQXdHOvvfmU=";

X509Certificate2 certificate = new X509Certificate2(Convert.FromBase64String(certificateString), secureString);
using var rsaPrivateKey = certificate.GetRSAPrivateKey();
var decryptedSymmetricKey = rsaPrivateKey.Decrypt(Convert.FromBase64String(dataKey), RSAEncryptionPadding.OaepSHA1);

var decypted = AesDecrypt(Convert.FromBase64String(data), decryptedSymmetricKey);
Console.WriteLine(System.Text.UTF8Encoding.UTF8.GetString(decypted));

static byte[] AesDecrypt(byte[] dataToDecrypt, byte[] key)
{
    try
    {
        using var cryptoServiceProvider = new AesCryptoServiceProvider
        {
            Mode = CipherMode.CBC,
            Padding = PaddingMode.PKCS7,
            Key = key
        };
        var numArray = new byte[16]; //16 is the IV size for the decryption provider required by specification
        Array.Copy(key, numArray, numArray.Length);
        cryptoServiceProvider.IV = numArray;
        using var memoryStream = new MemoryStream();
        using var cryptoStream = new CryptoStream(memoryStream, cryptoServiceProvider.CreateDecryptor(), CryptoStreamMode.Write);
        cryptoStream.Write(dataToDecrypt, 0, dataToDecrypt.Length);
        cryptoStream.FlushFinalBlock();
        return memoryStream.ToArray();
    }
    catch (Exception ex)
    {
        throw new ApplicationException("Unexpected error occurred while trying to decrypt the input", ex);
    }
}