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Digital SignatureThe term digital signature describes different methods to sign documents, in order to definitely identify the creator of document and to confirm the correctness and the validity of the document content.

Examples of technologies for digital signatures are User Identification and Passwords, digital signatures via smart cards and usage of biometrical procedures.

A digital signature should be the electronic pendant to a handwritten signature.

Features of a Digital Signature

The digital signature of a document is an encrypted fingerprint of the document content with the private key of the sender.

The digital signature ensures the integrity of the document and the identity of the signer.

Indeed a manipulation of the document during transit cannot be prevented, but the receiver can recogn1ize the manipulation doubtlessly.

The signed document can be changed neither by the signer nor by the receiver without a trace.

Technical Computing of the Digital Signature

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Functionality of a Digital Signature

Characteristics of a digital Signature

Authenticity

o A digital signature must clearly proof the Identity of the sender. This is

the case, when only theo Creator of the document is able to create the digital signature.

Integrity/Non-transferability

o The transmitted data are protected against intended or

unintended manipulation. The digital signature is valid only in connection with the document, i.e. it cannot be transferred to another document.

Liability

o The sender can deny the creatorship. Therefore a legally

binding communication must be guaranteed.

Verifiability

o The receiver of a document can doubtlessly check the digital signature,

i.e. verify or falsify.

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Digital Signatures in Forms 

UseSignatures can be used in forms on both the client side and, if implemented by the application, on the server side. A client-side signature gives the end user the option of signing a completed form in a signature field. A signature refers to the entire form at the time it is signed and guarantees the integrity of all data in the form. A signature is assigned to the document version in which it was set. Any changes to the data of this version invalidate the signature. If data is subsequently entered in the input fields, you are informed when the signature is checked. The check can be made on the server side or on the client side.

PrerequisitesServer-Side and Client-Side Signatures

The same prerequisites apply as for certification.

Client-Side SignaturesThe following additional prerequisites apply to client-side signatures:

To sign a form, you use Adobe Acrobat or Adobe Reader. To enable a user to set a signature when using Adobe Reader, the

appropriate Reader usage rights must be set in the form. Any interactive forms created with Web Dynpro for Java or ABAP have Reader usage rights automatically.

If the form is also certified, then the permitted changes must be set so that the certification is not invalidated when the form is signed. For more information, see features in Certification of Forms.

FeaturesSigning a Form

You set a signature in a form in a signature field. If a form contains multiple signature fields, then multiple signatures are possible.

Depending on the signature fields used when the form layout is created in Adobe LiveCycle Designer, the form can function in one of the following ways. The developer of the form determines which of these methods is used:5 | P a g e

After the form has been signed, all form fields are then locked against further input. Nor can you set any further signatures. If multiple signatures are used, this guarantees that the last signature protects all previously entered data and signatures from being deleted from the form.

After the form has been signed, only form fields are locked against further input of data. You can still enter data in any signature fields in the form. This enables you to set further (multiple) signatures.

In both previous options, it is possible to exclude input fields from being locked. After the form has been signed, only certain input fields (individual fields or groups of fields) are then locked against further input or changes.

You can sign a form on either the server side or the client side.

Signing a Form on the Server Side When you sign a form on the server side, you are prompted to specify

the name of the certificate. However, the application can also select the certificate automatically; this means that you do not need to access certificates as an end user.

Signing a Form on the Client Side To set a client-side signature (that is, your personal signature) use

Adobe Acrobat or Adobe Reader and your own certificates. For more information, see the online help for Adobe Acrobat or Adobe Reader.

 

Checking the Signature

You can check whether the signature of a form is valid or invalid. If a form contains multiple signatures, the check gives you a result for each signature.

Checking Signatures on the Server Side This function is enabled if your application implements server-side

checks on signatures in forms. The result of the check is a message about the status of the signature.

Client-Side Signature Check by the End User You can display information about signatures in the form and their

validity in Adobe Acrobat or Adobe Reader. For more information, see the online help for Adobe Acrobat or Adobe Reader.

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Digital signature in Adobe forms configuration.

A digital signature is a security mechanism for protecting digital data. The digital signature does the same function for processing digital data as hand written signature does for the paper based documents.  

Step1: SFP is the transaction to create adobe form. Provide the interface name and click on create button.  

  

Provide the description and save it.

Activate the interface and come back to initial screen of form builder.  

Step2: Provide the form name and click on create button.  

  

Provide the interface name and form description.  

Select the radio button ‘windows certification store’    

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The following Add Digital ID screen will appear when click on Next button and fill the related information.  

Now click on finish button.

Click on sign button as shown below.  

  

Now the created signature will appear on the signatory field as shown below.  

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Click on signature field, you will get the pop up box as shown below.

If you want to check the signature properties then click on signature properties button.  

If the signature is valid then you will get 'Signed and all signatures are valid' message appear at the top of the window.  

Here we can also change the field entries even after the signature field has been filled. When saving the form after we modified the any of the field entries in the form,

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you will get the following message at the top ‘Signed and all signatures are valid, but with unsigned changes after the last signature’.  

Click on signature panel at the top right side corner (Shown on above picture), there you can find the log as shown below.

When you click on highlighted statement under Form Fields Filled In, it would show the modified value of the field. And also you can check the value before modification in the Click to view this version under signature details.  

  

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Step3: Drag and drop the system field date to context tab.  

Step4: Go to layout tab,  

Drag the date field to layout editor.

Drag the signature field from library to layout editor as shown.  

Activate the form.  

Step5: Execute the form.  

Sign icon (Marked as Yellow color) as shown in tool bar is in disable mode. After the signature has been filled this icon becomes enable mode.  

Step6: Steps to create digital signature  

Click on signature field.

The following screen appears.  

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Now select the radio button ‘A new digital ID I want to create now’ and click on next button.  

Clicking on next button, the following screen appears as shown below.      

               

When selected New PKCS#12 digital ID file:  

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Click on Next button.  

Provide the required information and press Next button as shown below.

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We get the following screen. It asks for password. Provide the password and press finish button.  

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We get the following screen.  

  

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After providing the password only you can able to sign in. Suppose if you press the sign button without giving password, it asks for password saying that ‘A password is required to use this digital ID’.  

Now press the sign button. The signature would be appeared in signature field.  

In the above two cases, we can able to change the field entries after the signature field is filled in the form. But, we can also have an option to avoid / restrict making changes to the content of the fields (‘Date’ in this case) once the signature field is filled.  

Now go to library tab-Web Dynpro native. Drag and drop the signature-sign and lock to layout editor.  

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Save and activate the form.  

Execute the form.  

Click on signature lock field. The following screen appears. Select the existing id or create new id as shown below.  

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Select ID Phani

  

Click on sign button.  

Now the date field becomes locked. We can’t modify the value. In this way we can lock the fields after the signature has been done.

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