TNVAT DSC User Manual
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Commercial Taxes Department
Government of Tamil Nadu
Tamil Nadu VAT Implementation,
Guide for Using Digital Signature Certificate (DSC)
January, 2015
Version 1.0
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Contents
1. Introduction ........................................................................................................ 6
1.1 Approach ................................................................................................................................. 6
1.2 Login ........................................................................................................................................ 6
2. Map Digital Certificate ....................................................................................... 8
3. E-registration ................................................................................................... 12
4. Login with Digital Signature ........................................................................... 16
5. Un Map Digital Certificate ............................................................................... 18
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List of Figures
Figure 1: Login Screen ............................................................................................................................ 7
Figure 2: Home Screen ........................................................................................................................... 7
Figure 3: Map Digital Certificate Screen ................................................................................................. 8
Figure 4: Applet Screen for Mapping Digital Certificate .......................................................................... 9
Figure 5: Provide Password for Mapping Digital Certificate ................................................................. 10
Figure 6: Certificate Details with Mapped Digital Certificate ................................................................. 10
Figure 7: List of Mapped Certificates .................................................................................................... 11
Figure 8: e-Registration Form Type Selection Screen .......................................................................... 12
Figure 9: e-Registration Screen ............................................................................................................ 13
Figure 10: List of mapped Digital Certificates on e-Registration Screen .............................................. 13
Figure 11: Applet to Sign XML .............................................................................................................. 14
Figure 12: Generated Signed XML ....................................................................................................... 15
Figure 13: Login Page ........................................................................................................................... 16
Figure 14: Popup to login with Digital Signature ................................................................................... 17
Figure 15: Home Page after Successful Login ..................................................................................... 17
Figure 16: List of all mapped Digital Certificates................................................................................... 18
Figure 17: Un Map Digital Certificate .................................................................................................... 19
Figure 18: Un Map Certificate Success page ....................................................................................... 19
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List of Abbreviations
Table 1: List of Abbreviations
Abbreviation
Description
LT
Luxury tax
TCS
Tata Consultancy Services Ltd
TIN
Tax Payer’s Identification Number
TN
Tamil Nadu
TNCTD
Tamil Nadu Commercial Taxes Department
TNSWAN
Tamil Nadu State Wide Area Network
VAT
Value Added Tax
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1. Introduction
Digital certificate is the electronic counterpart of an ID card, such as a driver's license or passport.
The validity of a digital certificate is based on similar systems to those used to issue physical ID
cards. The certification authority issues a digital certificate. The digital certificate contains
information about who the certificate was issued to, as well as the certifying authority that issued
it. Additionally, some certifying authorities may themselves be certified by a hierarchy of one or
more certifying authorities, and this information is also part of the certificate. When a digital
certificate is used to sign documents and software, this ID information is stored with the signed
item in a secure and verifiable form so that it can be displayed to a user to establish a trust
relationship.
Digital certificates use a cryptographic technology called public-key cryptography to sign software
publications and to verify the integrity of the certificate itself. Public key cryptography uses a
matched pair of encryption and decryption keys called a public key and a private key. The public-
key cryptography algorithms perform a one-way transformation of the data they are applied to, so
that data that is encrypted with one key can only be decrypted by the other key. Additionally,
each key uses a sufficiently large value to make it computationally infeasible to derive a private
key from its corresponding public key. For this reason, a public key can be made widely available
without posing a risk to security.
1.1 Approach
TCS shall provide an in-house component to provide digital certificate based solution. This
component shall be an applet which would be loaded in the browser and would perform various
operations like – mapping a digital certificate of the dealer, signing web form or signing an xml
document.
This component shall read the certificates from an e-token and display the certificate details
including Alias of the certificate, Serial Number, Subject, Issuer, type and the path of the
certificate.
The same component shall be used for mapping the dealer’s certificate in the database. In order
to map the certificate, the end user shall select the certificate and click on submit button. On
clicking the same, public key, serial number, issuer, subject and expiry date shall be stored in
database.
The component shall ask for various details including the file to be signed and the output directory
where the signed document is to be written.
Once the signing process is done, end user would be given the path of the final directory.
After the signed document gets uploaded, server shall verify the signature against the mapped
signature of the dealer.
1.2 Login
To get the access of Map Digital Signature functionality, the dealer needs to get logged in web
portal.
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Below are the steps to log in to TNVAT Portal.
1. Click on Portal Home Page Link for Login.
Figure 1: Login Screen
2. Home screen will be displayed after Login.
Figure 2: Home Screen
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2. Map Digital Certificate
Any dealer who wants to use Digital Certificate for logging in and/or for signing, needs to first map
that digital certificate with the portal. Once mapped, dealer can use that certificate for logging in
and/or for signing as selected.
Below are the steps to map digital certificate:
1. Click on General->Map Digital Certificate link from left pane. Below mentioned
screen appears after the dealer clicks on “Map Digital Certificate”.
Figure 3: Map Digital Certificate Screen
2. Select purpose.
If user selects Logging with signing then user can use it for logging and signing
both purposes.
If user selects Logging then user can use digital signature for logging in only.
If user select Signing then user can use digital signature as Signing only.
3. Click on 'Map Digital Certificate’ link provided on right side of purpose. An applet will
be displayed which allows the dealer to map the digital certificate.
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Figure 4: Applet Screen for Mapping Digital Certificate
4. Click on browse button under Token Settings tab. In order to map the digital
certificate, dealer needs to provide the path of the .dll file from the system for the
plugged in token. After selecting the same, system will ask for the password of the
token.
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Figure 5: Provide Password for Mapping Digital Certificate
5. If password gets validated, system will display Digital Certificate details.
Figure 6: Certificate Details with Mapped Digital Certificate
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6. Click on Submit button to Map the digital certificate. Dealer would be shown a
success page once the certificate gets mapped and it will be displayed on screen.
Figure 7: List of Mapped Certificates
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3. E-registration
If dealer wants to apply for registration with signed XML, he can use the already mapped
certificate and upload the signed XML.
Below are the steps to apply for e-Registration with digital certificate:
1. Click e-Registration link from the e-Services left menu pane. Below mentioned
screen shall appear for selecting appropriate tax type. Dealer selects the form type
and clicks on Next button.
Figure 8: e-Registration Form Type Selection Screen
2. The below mentioned screen displays the details which are captured during selected
registration. Dealer would be given an option to sign the XML which is to be
uploaded.
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Figure 9: e-Registration Screen
3. Select Yes in ‘Is application Digitally Signed?’ option. On selecting, a list of all the
certificates mapped with the logged in dealer will be displayed.
Figure 10: List of mapped Digital Certificates on e-Registration Screen
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4. To sign validated XML with the selected certificate, click “Click Here to Sign XML”
link. Dealer shall be displayed an applet to sign the XML as shown below.
Figure 11: Applet to Sign XML
5. Select the file (generated XML) which needs to be signed by clicking Browse button
against field Input File. Select Output Directory path for saving signed XML. Select
certificate against Library under Token Settings and click on Submit. On submit
the signed filed will be generated and saved at the selected Output Directory.
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Figure 12: Generated Signed XML
6. Dealer shall upload the signed XML to complete the registration process.
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4. Login with Digital Signature
Any dealer who wants to use Digital Certificate for logging in, needs to first map that digital
certificate with the portal. Once mapped, dealer can use that certificate for logging in.
Below are the steps to login with Digital Signature:
1. Select ‘Login with’ as Digital Signature in Login Screen.
Figure 13: Login Page
2. A popup is opened to select the certificate with which dealer wants to login and
which is mapped with purpose as Logging in by dealer.
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Figure 14: Popup to login with Digital Signature
3. Once dealer has selected valid certificate and has provided valid password, he/she
will be able to login successfully and will be redirected to home page as shown
below.
Figure 15: Home Page after Successful Login
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5. Un Map Digital Certificate
Un Map Digital Certificate functionality is used to remove existing mapped digital certificate from
the Web Portal. After that dealer cannot use that Digital Certificate for Logging and/or for Signing
the functionalities.
Below are the steps to un map Digital Certificate:
1. Click on General->Map Digital Certificate link in left page.
2. A list of all mapped Digital Certificate(s) will be displayed.
Figure 16: List of all mapped Digital Certificates
3. Select Digital Certificate which you want to un map from your account and click on
UnMap Certificate button.
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Figure 17: Un Map Digital Certificate
4. On submit, a success message will be displayed.
Figure 18: Un Map Certificate Success page
