Java Requires Chilkat v11.0.0+

Aadhaar Paperless Offline e-kyc

See more XML Digital Signatures Examples

Opens an encrypted .zip containing Aadhaar Paperless Offline e-KYC XML. Gets the XML and validates the digital signature. Then computes the hash for the mobile number and Email ID. Chilkat2 Java

import com.chilkatsoft.chilkat2.BinData;
import com.chilkatsoft.chilkat2.Cert;
import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Crypt2;
import com.chilkatsoft.chilkat2.PublicKey;
import com.chilkatsoft.chilkat2.Xml;
import com.chilkatsoft.chilkat2.XmlDSig;
import com.chilkatsoft.chilkat2.Zip;
import com.chilkatsoft.chilkat2.ZipEntry;

public class ChilkatExample {

    public static void main(String[] args) {
        // This example requires the Chilkat API to have been previously unlocked.
        // See Global Unlock Sample for sample code.

        // Open the .zip containing the Aadhaar Paperless Offline e-KYC XML.
        // The .zip is encrypted using the "Share Phrase".
        Zip zip = new Zip();
        try {
            zip.openZip("qa_data/xml_dsig/offline_paperless_kyc.zip");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // The .zip should contain 1 XML file.
        ZipEntry entry = new ZipEntry();
        try {
            zip.entryAt(0, entry);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // To get the contents, we need to specify the Share Phrase.
        String sharePhrase = "Lock@487";
        zip.setDecryptPassword(sharePhrase);

        BinData bdXml = new BinData();
        // The XML file will be unzipped into the bdXml object.
        try {
            entry.unzipToBd(bdXml);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // First verify the XML digital signature.
        XmlDSig dsig = new XmlDSig();
        try {
            dsig.loadSignatureBd(bdXml);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        // The UIDAI XML signature does not contain the KeyInfo, so we must load the uidai certificate
        // and indicate that its public key is to be used for verifying the signature.
        Cert cert = new Cert();
        try {
            cert.loadFromFile("qa_data/xml_dsig/uidai_auth_sign_prod_2023.cer");
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

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

        dsig.setPublicKey(pubKey);

        // The XML in this example contains only 1 signature.
        boolean bVerifyReferenceDigests = true;
        try {
            dsig.verifySignature(bVerifyReferenceDigests);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            System.out.println("The signature was not valid.");
            return;
        }

        System.out.println("The XML digital signature is valid.");

        // Let's compute the hash for the Mobile Number.

        //     Hashing logic for Mobile Number :
        //     Sha256(Sha256(Mobile+SharePhrase))*number of times last digit of Aadhaar number
        //     (Ref ID field contains last 4 digits).
        //
        //     Example :
        //     Mobile: 1234567890
        //     Aadhaar Number:XXXX XXXX 3632
        //     Passcode : Lock@487
        //     Hash: Sha256(Sha256(1234567890Lock@487))*2
        //     In case of Aadhaar number ends with Zero we will hashed one time.

        Crypt2 crypt = new Crypt2();
        crypt.setHashAlgorithm("sha256");
        crypt.setEncodingMode("hexlower");

        String strToHash = "1234567890Lock@487";
        BinData bdHash = new BinData();
        bdHash.appendString(strToHash, "utf-8");

        // Hash a number of times equal to the last digit of your Aadhaar number.
        // If the Aadhaar number ends with 0, then hash one time.
        // For this example, we'll just set the number of times to hash
        // for the case where an Aadhaar number ends in "9"
        int numTimesToHash = 9;
        for (int i = 1; i <= numTimesToHash; i++) {
            String tmpStr = crypt.hashBdENC(bdHash);
            bdHash.clear();
            bdHash.appendString(tmpStr, "utf-8");
        }

        System.out.println("Computed Mobile hash = " + bdHash.getString("utf-8"));

        // Let's get the mobile hash stored in the XML and compare it with our computed hash.
        Xml xml = new Xml();
        xml.loadBd(bdXml, true);
        String m_hash = xml.chilkatPath("UidData|Poi|(m)");

        System.out.println("Stored Mobile hash   = " + m_hash);

        // Now do the same thing for the email hash:

        strToHash = "abc@gm.comLock@487";
        bdHash.clear();
        bdHash.appendString(strToHash, "utf-8");

        for (int i = 1; i <= numTimesToHash; i++) {
            String tmpStr = crypt.hashBdENC(bdHash);
            bdHash.clear();
            bdHash.appendString(tmpStr, "utf-8");
        }

        System.out.println("Computed Email hash = " + bdHash.getString("utf-8"));

        String e_hash = xml.chilkatPath("UidData|Poi|(e)");
        System.out.println("Stored Email hash   = " + e_hash);
    }
}