public sealed class CryptoService : ICryptoService
{
public async Task<byte[]> SignFile(Stream document, CancellationToken cancellationToken = default)
{
if (document is null || document == Stream.Null || !document.CanSeek)
throw new CryptoSignerException("Stream входных данных для подписания невозможно редактировать!", StatusCode.InvalidRequest);

byte[] documentBuffer;

//создаём свой Stream документа
if (document is MemoryStream documentStream)
{
documentStream.Seek(0, SeekOrigin.Begin);
documentBuffer = documentStream.ToArray();
await documentStream.DisposeAsync();
}
else
await using (documentStream = new MemoryStream())
{
await document.CopyToAsync(documentStream, cancellationToken);
documentStream.Seek(0, SeekOrigin.Begin);
documentBuffer = documentStream.ToArray();
}

//получение сертификата
var storeMy = new X509Store(StoreName.My,
StoreLocation.CurrentUser);
storeMy.Open(OpenFlags.ReadOnly);
var certColl =
storeMy.Certificates.Find(X509FindType.FindBySerialNumber, "0166E7A50000B04C8049C2C3CBE96039B4", false);
using var x509Certificate = certColl[0];
var contentInfo = new ContentInfo(documentBuffer);
var signedCms = new SignedCms(contentInfo, true);
var cmsSigner = new CmsSigner(x509Certificate);
//подпись файла
signedCms.ComputeSignature(cmsSigner);
var signedCmsBuffer = signedCms.Encode();
signedCms.Decode(signedCmsBuffer);
//проверка подписи
signedCms.CheckSignature(false);
return signedCmsBuffer;
}
}

System.Security.Cryptography.CryptographicException: Could not determine signature algorithm for the signer certificate.
at System.Security.Cryptography.Pkcs.CmsSigner.Sign(ReadOnlyMemory`1 data, String contentTypeOid, Boolean silent, X509Certificate2Collection& chainCerts)
at System.Security.Cryptography.Pkcs.SignedCms.ComputeSignature(CmsSigner signer, Boolean silent)
at System.Security.Cryptography.Pkcs.SignedCms.ComputeSignature(CmsSigner signer)
at Gz.Invest.CryptoSigner.Services.CryptoService.SignFile(Stream document, CancellationToken cancellationToken) in C:\Uniteller\crypto-signer\src\Gz.Invest.CryptoSigner.Services\CryptoService.cs:line 48