uses WCrypt2........

................
var
  hCertStore: Pointer;
  pCertContext, pSignerCert: PCCERT_CONTEXT;
  subject: string;
begin
  // Open "MY" store
  hCertStore := CertOpenStore(CERT_STORE_PROV_SYSTEM, X509_ASN_ENCODING or PKCS_7_ASN_ENCODING,
                               0, CERT_SYSTEM_STORE_CURRENT_USER, PChar('MY'));

  pCertContext := nil;

  repeat
    pCertContext := CertEnumCertificatesInStore(hCertStore, pCertContext);
    if (pCertContext <> nil) then begin
      pSignerCert := CertDuplicateCertificateContext(pCertContext);

      Memo1.Lines.Add('HEX: ' + GetCertificateHEX2(pSignerCert));
      subject:=DecodeName(pSignerCert^.pCertInfo^.Subject);

      if Assigned(pSignerCert) then CertFreeCertificateContext(pSignerCert);
    end;
  until (pCertContext = nil);