ahoj,
muzes si pocist neco na vfp forum
https://groups.google.com/forum/#!forum/foxprokonkretni jednoduchy priklad
X509Certificate2 uidCert = new X509Certificate2("e:\\work\\eet\\Cert\\01000003.p12", "eet"
, X509KeyStorageFlags.Exportable);
RSACryptoServiceProvider csp = (RSACryptoServiceProvider)uidCert.PrivateKey;
RSACryptoServiceProvider privateKey1 = new RSACryptoServiceProvider();
privateKey1.ImportParameters(csp.ExportParameters(true));
//pkp
byte[] data = Encoding.UTF8.GetBytes(plaintext);
byte[] signature = privateKey1.SignData(data, "SHA256");
var pom = System.Convert.ToBase64String(signature);
String sPkp = System.Convert.ToBase64String(signature);
//bkp
SHA1 sha = new SHA1CryptoServiceProvider();
byte[] resSha = sha.ComputeHash(signature);
String sBkp = Regex.Replace(BitConverter.ToString(resSha).Replace("-", string.Empty), ".{8}(?!$)", "$0-");
//konec generovani pkp a bkp
jinak nejakou specifikaci mas tady
pro me byl spis hacek to podepisovani xml