Swift

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. Swift

func chilkatTest() {
    var success: Bool = 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".
    let zip = CkoZip()!
    success = zip.open(zipPath: "qa_data/xml_dsig/offline_paperless_kyc.zip")
    if success == false {
        print("\(zip.lastErrorText!)")
        return
    }

    // The .zip should contain 1 XML file.
    let entry = CkoZipEntry()!
    success = zip.entry(at: 0, entry: entry)
    if success == false {
        print("\(zip.lastErrorText!)")
        return
    }

    // To get the contents, we need to specify the Share Phrase.
    var sharePhrase: String? = "Lock@487"
    zip.decryptPassword = sharePhrase

    let bdXml = CkoBinData()!
    // The XML file will be unzipped into the bdXml object.
    success = entry.unzip(toBd: bdXml)
    if success == false {
        print("\(entry.lastErrorText!)")
        return
    }

    // First verify the XML digital signature.
    let dsig = CkoXmlDSig()!
    success = dsig.loadSignatureBd(binData: bdXml)
    if success == false {
        print("\(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.
    let cert = CkoCert()!
    success = cert.load(fromFile: "qa_data/xml_dsig/uidai_auth_sign_prod_2023.cer")
    if success == false {
        print("\(cert.lastErrorText!)")
        return
    }

    // Get the certificate's public key.
    let pubKey = CkoPublicKey()!
    cert.getPublicKey(pubKey: pubKey)

    dsig.setPublicKey(pubKey: pubKey)

    // The XML in this example contains only 1 signature.
    var bVerifyReferenceDigests: Bool = true
    var bVerified: Bool = dsig.verifySignature(verifyReferenceDigests: bVerifyReferenceDigests)
    if bVerified == false {
        print("\(dsig.lastErrorText!)")
        print("The signature was not valid.")
        return
    }

    print("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.

    let crypt = CkoCrypt2()!
    crypt.hashAlgorithm = "sha256"
    crypt.encodingMode = "hexlower"

    var strToHash: String? = "1234567890Lock@487"
    let bdHash = CkoBinData()!
    success = bdHash.appendString(str: strToHash, charset: "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: Int = 9
    var i: Int
    for i = 1; i <= numTimesToHash; i++ {
        var tmpStr: String? = crypt.hashBdENC(bd: bdHash)
        bdHash.clear()
        bdHash.appendString(str: tmpStr, charset: "utf-8")
    }

    print("Computed Mobile hash = \(bdHash.getString(charset: "utf-8")!)")

    // Let's get the mobile hash stored in the XML and compare it with our computed hash.
    let xml = CkoXml()!
    success = xml.loadBd(bd: bdXml, autoTrim: true)
    var m_hash: String? = xml.chilkatPath(cmd: "UidData|Poi|(m)")

    print("Stored Mobile hash   = \(m_hash!)")

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

    strToHash = "abc@gm.comLock@487"
    bdHash.clear()
    success = bdHash.appendString(str: strToHash, charset: "utf-8")

    for i = 1; i <= numTimesToHash; i++ {
        var tmpStr: String? = crypt.hashBdENC(bd: bdHash)
        bdHash.clear()
        bdHash.appendString(str: tmpStr, charset: "utf-8")
    }

    print("Computed Email hash = \(bdHash.getString(charset: "utf-8")!)")

    var e_hash: String? = xml.chilkatPath(cmd: "UidData|Poi|(e)")
    print("Stored Email hash   = \(e_hash!)")

}