Delphi ActiveX Requires Chilkat v11.0.0+

Get a Certificate's Key Size

See more Certificates Examples

Demonstrates how to get the RSA key size of a certificate (for example, 1024-bit, 2048-bit, etc.) Delphi ActiveX

var
success: Integer;
sbCertBase64: TChilkatStringBuilder;
cert: TChilkatCert;
pubKey: TPublicKey;
numBits: Integer;
xml: TChilkatXml;
binDat: TChilkatBinData;

begin
success := 0;

//  For this example, I have a certificate in raw base64 format (not PEM),
//  that looks like this:  "MIIGkDCCBHigAwIBAgIUMDA ... s/iqLsLA=="
sbCertBase64 := TChilkatStringBuilder.Create(Self);
success := sbCertBase64.LoadFile('qa_data/certs/base64Cert.txt','utf-8');

cert := TChilkatCert.Create(Self);
success := cert.LoadFromBase64(sbCertBase64.GetAsString());
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;

//  Get the public key.
pubKey := TPublicKey.Create(Self);
cert.GetPublicKey(pubKey.ControlInterface);

numBits := pubKey.KeySize;
Memo1.Lines.Add('Number of bits = ' + IntToStr(numBits));

//  If using an older version of Chilkat, the key size can be obtained like this:
xml := TChilkatXml.Create(Self);
xml.LoadXml(pubKey.GetXml());

binDat := TChilkatBinData.Create(Self);
binDat.AppendEncoded(xml.GetChildContent('Modulus'),'base64');

numBits := 8 * binDat.NumBytes;
Memo1.Lines.Add('Number of bits = ' + IntToStr(numBits));