(Ruby) 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

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

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".
zip = Chilkat::CkZip.new()
success = zip.OpenZip("qa_data/xml_dsig/offline_paperless_kyc.zip")
if (success == false)
    print zip.lastErrorText() + "\n";
    exit
end

# The .zip should contain 1 XML file.
entry = Chilkat::CkZipEntry.new()
success = zip.EntryAt(0,entry)
if (success == false)
    print zip.lastErrorText() + "\n";
    exit
end

# To get the contents, we need to specify the Share Phrase.
sharePhrase = "Lock@487"
zip.put_DecryptPassword(sharePhrase)

bdXml = Chilkat::CkBinData.new()
# The XML file will be unzipped into the bdXml object.
success = entry.UnzipToBd(bdXml)
if (success == false)
    print entry.lastErrorText() + "\n";
    exit
end

# First verify the XML digital signature.
dsig = Chilkat::CkXmlDSig.new()
success = dsig.LoadSignatureBd(bdXml)
if (success == false)
    print dsig.lastErrorText() + "\n";
    exit
end

# 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 = Chilkat::CkCert.new()
success = cert.LoadFromFile("qa_data/xml_dsig/uidai_auth_sign_prod_2023.cer")
if (success == false)
    print cert.lastErrorText() + "\n";
    exit
end

# Get the certificate's public key.
pubKey = Chilkat::CkPublicKey.new()
cert.GetPublicKey(pubKey)

dsig.SetPublicKey(pubKey)

# The XML in this example contains only 1 signature.
bVerifyReferenceDigests = true
bVerified = dsig.VerifySignature(bVerifyReferenceDigests)
if (bVerified == false)
    print dsig.lastErrorText() + "\n";
    print "The signature was not valid." + "\n";
    exit
end

print "The XML digital signature is valid." + "\n";

# 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.

crypt = Chilkat::CkCrypt2.new()
crypt.put_HashAlgorithm("sha256")
crypt.put_EncodingMode("hexlower")

strToHash = "1234567890Lock@487"
bdHash = Chilkat::CkBinData.new()
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"
numTimesToHash = 9

for i in 1 .. numTimesToHash
    tmpStr = crypt.hashBdENC(bdHash)
    bdHash.Clear()
    bdHash.AppendString(tmpStr,"utf-8")
end

print "Computed Mobile hash = " + bdHash.getString("utf-8") + "\n";

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

print "Stored Mobile hash   = " + m_hash + "\n";

# Now do the same thing for the email hash:

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

for i in 1 .. numTimesToHash
    tmpStr = crypt.hashBdENC(bdHash)
    bdHash.Clear()
    bdHash.AppendString(tmpStr,"utf-8")
end

print "Computed Email hash = " + bdHash.getString("utf-8") + "\n";

e_hash = xml.chilkatPath("UidData|Poi|(e)")
print "Stored Email hash   = " + e_hash + "\n";