(JavaScript) Aadhaar Paperless Offline e-kyc

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.

Note: This example requires Chilkat v11.0.0 or greater.

For more information, see https://uidai.gov.in/ecosystem/authentication-devices-documents/about-aadhaar-paperless-offline-e-kyc.html

Note

This example is intended for running within a Chilkat.Js embedded JavaScript engine. All Chilkat JavaScript examples require Chilkat v11.4.0 or greater.

var success = false;

// 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".
var zip = new CkZip();
success = zip.OpenZip("qa_data/xml_dsig/offline_paperless_kyc.zip");
if (success == false) {
    console.log(zip.LastErrorText);
    return;
}

// The .zip should contain 1 XML file.
var entry = new CkZipEntry();
success = zip.EntryAt(0,entry);
if (success == false) {
    console.log(zip.LastErrorText);
    return;
}

// To get the contents, we need to specify the Share Phrase.
var sharePhrase = "Lock@487";
zip.DecryptPassword = sharePhrase;

var bdXml = new CkBinData();
// The XML file will be unzipped into the bdXml object.
success = entry.UnzipToBd(bdXml);
if (success == false) {
    console.log(entry.LastErrorText);
    return;
}

// First verify the XML digital signature.
var dsig = new CkXmlDSig();
success = dsig.LoadSignatureBd(bdXml);
if (success == false) {
    console.log(dsig.LastErrorText);
    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.
var cert = new CkCert();
success = cert.LoadFromFile("qa_data/xml_dsig/uidai_auth_sign_prod_2023.cer");
if (success == false) {
    console.log(cert.LastErrorText);
    return;
}

// Get the certificate's public key.
var pubKey = new CkPublicKey();
cert.GetPublicKey(pubKey);

dsig.SetPublicKey(pubKey);

// The XML in this example contains only 1 signature.
var bVerifyReferenceDigests = true;
var bVerified = dsig.VerifySignature(bVerifyReferenceDigests);
if (bVerified == false) {
    console.log(dsig.LastErrorText);
    console.log("The signature was not valid.");
    return;
}

console.log("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.

var crypt = new CkCrypt2();
crypt.HashAlgorithm = "sha256";
crypt.EncodingMode = "hexlower";

var strToHash = "1234567890Lock@487";
var bdHash = new CkBinData();
success = 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"
var numTimesToHash = 9;
var i;
for (i = 1; i <= numTimesToHash; i++) {
    var tmpStr = crypt.HashBdENC(bdHash);
    bdHash.Clear();
    bdHash.AppendString(tmpStr,"utf-8");
}

console.log("Computed Mobile hash = " + bdHash.GetString("utf-8"));

// Let's get the mobile hash stored in the XML and compare it with our computed hash.
var xml = new CkXml();
success = xml.LoadBd(bdXml,true);
var m_hash = xml.ChilkatPath("UidData|Poi|(m)");

console.log("Stored Mobile hash   = " + m_hash);

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

strToHash = "abc@gm.comLock@487";
bdHash.Clear();
success = bdHash.AppendString(strToHash,"utf-8");

for (i = 1; i <= numTimesToHash; i++) {
    var tmpStr = crypt.HashBdENC(bdHash);
    bdHash.Clear();
    bdHash.AppendString(tmpStr,"utf-8");
}

console.log("Computed Email hash = " + bdHash.GetString("utf-8"));

var e_hash = xml.ChilkatPath("UidData|Poi|(e)");
console.log("Stored Email hash   = " + e_hash);