(Swift 2) 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.

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

Chilkat Downloads for the Swift Programming Language MAC OS X (Cocoa) Objective-C/Swift Libs iOS Objective-C/Swift Libs

func chilkatTest() {
    // 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()
    var success: Bool = zip.OpenZip("qa_data/xml_dsig/offline_paperless_kyc.zip")
    if success == false {
        print("\(zip.LastErrorText)")
        return
    }

    // The .zip should contain 1 XML file.
    var entry: CkoZipEntry? = zip.GetEntryByIndex(0)
    if zip.LastMethodSuccess == 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!.UnzipToBd(bdXml)
    if success == false {
        print("\(entry!.LastErrorText)")
        entry = nil
        return
    }

    entry = nil

    // First verify the XML digital signature.
    let dsig = CkoXmlDSig()
    success = dsig.LoadSignatureBd(bdXml)
    if success != true {
        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.LoadFromFile("qa_data/xml_dsig/uidai_auth_sign_prod_2023.cer")
    if success != true {
        print("\(cert.LastErrorText)")
        return
    }

    // Get the certificate's public key.
    var pubKey: CkoPublicKey? = cert.ExportPublicKey()
    success = dsig.SetPublicKey(pubKey)
    pubKey = nil

    // The XML in this example contains only 1 signature.
    var bVerifyReferenceDigests: Bool = true
    var bVerified: Bool = dsig.VerifySignature(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(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(bdHash)
        bdHash.Clear()
        bdHash.AppendString(tmpStr, charset: "utf-8")
    }

    print("Computed Mobile hash = \(bdHash.GetString("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(bdXml, autoTrim: true)
    var m_hash: String? = xml.ChilkatPath("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(strToHash, charset: "utf-8")

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

    print("Computed Email hash = \(bdHash.GetString("utf-8"))")

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

}