Xbase++ 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. Xbase++

LOCAL nSuccess
LOCAL oZip
LOCAL oEntry
LOCAL cSharePhrase
LOCAL oBdXml
LOCAL oDsig
LOCAL oCert
LOCAL oPubKey
LOCAL nBVerifyReferenceDigests
LOCAL nBVerified
LOCAL oCrypt
LOCAL cStrToHash
LOCAL oBdHash
LOCAL nNumTimesToHash
LOCAL i
LOCAL cTmpStr
LOCAL oXml
LOCAL cM_hash
LOCAL cTmpStr
LOCAL cE_hash

nSuccess := 0

//  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".
oZip := CreateObject("Chilkat.Zip")
nSuccess := oZip:OpenZip("qa_data/xml_dsig/offline_paperless_kyc.zip")
IF (nSuccess == 0)
    ? oZip:LastErrorText
    oZip:destroy()
    RETURN
ENDIF

//  The .zip should contain 1 XML file.
oEntry := CreateObject("Chilkat.ZipEntry")
nSuccess := oZip:EntryAt(0, oEntry)
IF (nSuccess == 0)
    ? oZip:LastErrorText
    oZip:destroy()
    oEntry:destroy()
    RETURN
ENDIF

//  To get the contents, we need to specify the Share Phrase.
cSharePhrase := "Lock@487"
oZip:DecryptPassword := cSharePhrase

oBdXml := CreateObject("Chilkat.BinData")
//  The XML file will be unzipped into the bdXml object.
nSuccess := oEntry:UnzipToBd(oBdXml)
IF (nSuccess == 0)
    ? oEntry:LastErrorText
    oZip:destroy()
    oEntry:destroy()
    oBdXml:destroy()
    RETURN
ENDIF

//  First verify the XML digital signature.
oDsig := CreateObject("Chilkat.XmlDSig")
nSuccess := oDsig:LoadSignatureBd(oBdXml)
IF (nSuccess == 0)
    ? oDsig:LastErrorText
    oZip:destroy()
    oEntry:destroy()
    oBdXml:destroy()
    oDsig:destroy()
    RETURN
ENDIF

//  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.
oCert := CreateObject("Chilkat.Cert")
nSuccess := oCert:LoadFromFile("qa_data/xml_dsig/uidai_auth_sign_prod_2023.cer")
IF (nSuccess == 0)
    ? oCert:LastErrorText
    oZip:destroy()
    oEntry:destroy()
    oBdXml:destroy()
    oDsig:destroy()
    oCert:destroy()
    RETURN
ENDIF

//  Get the certificate's public key.
oPubKey := CreateObject("Chilkat.PublicKey")
oCert:GetPublicKey(oPubKey)

oDsig:SetPublicKey(oPubKey)

//  The XML in this example contains only 1 signature.
nBVerifyReferenceDigests := 1
nBVerified := oDsig:VerifySignature(nBVerifyReferenceDigests)
IF (nBVerified == 0)
    ? oDsig:LastErrorText
    ? "The signature was not valid."
    oZip:destroy()
    oEntry:destroy()
    oBdXml:destroy()
    oDsig:destroy()
    oCert:destroy()
    oPubKey:destroy()
    RETURN
ENDIF

? "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.

oCrypt := CreateObject("Chilkat.Crypt2")
oCrypt:HashAlgorithm := "sha256"
oCrypt:EncodingMode := "hexlower"

cStrToHash := "1234567890Lock@487"
oBdHash := CreateObject("Chilkat.BinData")
nSuccess := oBdHash:AppendString(cStrToHash, "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"
nNumTimesToHash := 9

FOR i := 1 TO nNumTimesToHash
    cTmpStr := oCrypt:HashBdENC(oBdHash)
    oBdHash:Clear()
    oBdHash:AppendString(cTmpStr, "utf-8")
NEXT

? "Computed Mobile hash = " + oBdHash:GetString("utf-8")

//  Let's get the mobile hash stored in the XML and compare it with our computed hash.
oXml := CreateObject("Chilkat.Xml")
nSuccess := oXml:LoadBd(oBdXml, 1)
cM_hash := oXml:ChilkatPath("UidData|Poi|(m)")

? "Stored Mobile hash   = " + cM_hash

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

cStrToHash := "abc@gm.comLock@487"
oBdHash:Clear()
nSuccess := oBdHash:AppendString(cStrToHash, "utf-8")

FOR i := 1 TO nNumTimesToHash
    cTmpStr := oCrypt:HashBdENC(oBdHash)
    oBdHash:Clear()
    oBdHash:AppendString(cTmpStr, "utf-8")
NEXT

? "Computed Email hash = " + oBdHash:GetString("utf-8")

cE_hash := oXml:ChilkatPath("UidData|Poi|(e)")
? "Stored Email hash   = " + cE_hash

oZip:destroy()
oEntry:destroy()
oBdXml:destroy()
oDsig:destroy()
oCert:destroy()
oPubKey:destroy()
oCrypt:destroy()
oBdHash:destroy()
oXml:destroy()