Java 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.) Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.PublicKey;
import com.chilkatsoft.chilkat2.StringBuilder;
import com.chilkatsoft.chilkat2.Xml;

public class ChilkatExample {

    public static void main(String[] args) {
        // For this example, I have a certificate in raw base64 format (not PEM),
        // that looks like this:  "MIIGkDCCBHigAwIBAgIUMDA ... s/iqLsLA=="
        StringBuilder sbCertBase64 = new StringBuilder();
        sbCertBase64.loadFile("qa_data/certs/base64Cert.txt", "utf-8");

        Cert cert = new Cert();
        try {
            cert.loadFromBase64(sbCertBase64.getAsString());
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // Get the public key.
        PublicKey pubKey = new PublicKey();
        cert.getPublicKey(pubKey);

        int numBits = pubKey.getKeySize();
        System.out.println("Number of bits = " + numBits);

        // If using an older version of Chilkat, the key size can be obtained like this:
        Xml xml = new Xml();
        xml.loadXml(pubKey.getXml());

        BinData binDat = new BinData();
        binDat.appendEncoded(xml.getChildContent("Modulus"), "base64");

        numBits = 8 * binDat.getNumBytes();
        System.out.println("Number of bits = " + numBits);
    }
}