Tcl

Google Authenticator Algorithm

See more Encryption Examples

Example code implementing the Google Authenticator algorithm. Tcl

load ./chilkat.dll

# This example assumes the Chilkat API to have been previously unlocked.
# See Global Unlock Sample for sample code.

# Generating TOTP Base32 Secret: 
# When you enable 2FA with a TOTP-based authenticator app, Google will provide you with a QR code
# that you can scan using the app. This QR code contains a TOTP base32 secret.
# You can also choose to view and copy the secret manually.

set secretBase32 "JBSWY3DPEHPK3PXP"

# Do the following to calculate the 6-digit decimal Google authenticator token for a base32 secret,
# given the current system date/time.
set crypt [new_CkCrypt2]

set otp [CkCrypt2_totp $crypt $secretBase32 "base32" "0" "" 30 6 -1 "sha1"]

puts "6-digit decimal token = $otp"

delete_CkCrypt2 $crypt