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frevvo supports Digital Signatures. Authenticated users can digitally sign a section, lock it down and prevent tampering with the data. Versions, previous to 5.1, allowed the form designer to put a section in a form that could be signed using a text rendering of the user's name (user credentials) or a previously uploaded signature image. The user must be be authenticated to the frevvo Server.  Wet signature capture is now available in Version 5.1. A wet signature is a signature that is entered or created at the time of form entry.  Wet Signatures make it possible for the user to enter the signature using either a track pad/mouse, stylus or a touch screen in use mode. This feature becomes very important when designing frevvo for Mobile devices. Refer to the PageBreak control for more information on mobile forms.

Both authenticated and non-authenticated users may sign a form using a wet signature. If authentication is required, Signed Sections should be used.

No special hardware is required. All you need is a smartphone or a computer with a browser that supports HTML5. View this video about frevvo Electronic Signatures feature.

On This Page:

Signatures can be added to any form using one of the methods listed:

The signature control only captures a handwritten signature image. It does not create a digital signature.  A signed section that is set to wet signature both captures a handwritten signature image and creates a digital signature over the contents of the section. See below.

Wet Signature Control

You can use the signature control to place a signature anywhere in your form. Wet signatures allow the user to enter their signature using either a track pad/mouse, stylus or a touch screen during form completion. Authentication to the frevvo server is not required. Wet signatures are supported on Signed Form Sections where the designer can choose text/image or wet signature formats.  Wet signatures will be optionally rendered on the pdf/print copy of the form. Your browser must support HTML5 canvas technology for proper signature entry functionality.  Here is a list of browsers that can be used:

  • Internet Explorer 9 +

  • Firefox 3.6 +

  • Chrome 6+

  • Safari 5.1+

  • IOS: Tablet: 3.2+, Phone: 3.1+

When designing a form with an electronic wet signature control, the captured signature is attached to the form submission as a PNG image attachment. Any Live Forms document actions affecting the form data includes the signature png image. For example, should you choose to post the data to your web application, then the signature png is part of that posted data. Should you choose to email the data, the signature png will be attached to the email. Finally, should you choose none of these things, then the captured signature png is available for downloading by browsing your submissions within frevvo. See View/Edit Submissions for the details.

Signed Sections

frevvo provides true digital signature functionality via a section control in your form. The granularity is at the section control, so that different parts of the form can be signed by different people rather than a signature being applied only to the entire form. You must be an authenticated user to sign a section whether you choose Wet Signature or Text/Signature Image on the section security tab in the designer.


Signed Section in multiple activities in a flow must contain the same controls in all the activities.

Digital Signature

The user must be authenticated to the frevvo server. Here is how it works:

frevvo uses public key cryptography. When a frevvo server is first started, it generates a public and a private key. This is automatically generated using the RSA algorithm. There is no official certificate authority (CA); however, if you want one you can supply your own public and private keys that are certified by some authority (like Verisign). An official CA is not required, since the data is signed by and verified by frevvo using keys generated by frevvo. You must keep the private key "private" by setting up good security practices to the frevvo server's disk. The public key may be shared with anyone and, in fact, if you manage the server as the admin user, and click on Security you can see the public key displayed there.

When a section is signed, the data in the section, together with a time stamp, the signing user, and a few other things are used to generate a message digest. The message digest is digitally signed using the private key. The signatures (there can be more than one) are included with the submission – in the repository and sent in the HTTP POST so you can save it yourself if you want.

When the form is re-initialized from the submission documents, you must also supply the signatures. The initialization process will verify that the data has not changed (i.e., has not been tampered with) and the signature is still valid. If the signature is not valid, it is removed and the entire Section is displayed with a visible error (large red background). If it is valid, there is a green background and the Section cannot be edited.



Wet Signature

You can choose the signature format for a signed section in your form. Select any section control on your form and click the Security tab in the properties panel. The bottom portion of the tab is relevant to signatures. Refer to Security Properties for information on the Role dropdown. The drop down select has three options:

  • None Required - no signature required, section not digitally signed.
  • Text/Signature Image - This is the same as selecting the signature check box in previous versions. An uploaded signature image for the user will be used, if one is available. The user's name will be printed otherwise.
  • Wet Signaturefrevvo will present the signature entry dialog to capture the user's signature.

The default value is None Required. The Must sign property makes the signature required. With Must sign, a form cannot be submitted or a workflow is not sent to the next person until the signature is added. Lock sign means that the next person in the workflow can not remove the signature and edit the signed data. A good use case is an employee performance review where the manager starts the form, and signs the review, and sends it to the employee. You would check Lock sign so the employee cannot unsign and edit the data entered by the manager.

Selecting None Required from the signature dropdown will change the signature format type to Text/Signature Image and disable None Required as a choice if Must Sign is checked.

Sections that are hidden/not hidden via a rule or the Visible property in the designer, behave as stated below with respect to Must Sign:

  • If the must sign section is visible, then you must sign to get the form valid, regardless of the section's required status.
  • If the must sign section is invisible and required and contains required controls, then the form cannot become valid.
  • If the must sign section is invisible and not required, then the section becomes valid and the form becomes valid.

All of the standard properties and settings apply to the signature control. For example, the required setting can be used to force the entry of a wet signature in order for the form to be valid (in use mode). You can change the width of the signature light box by changing the default value of 49% to another value.

Signed Sections and Wet Signatures in Use Mode

Here is an example of a standard signed section on a Leave Approval form when the signature property is set to Text/Signature Image and there is no signature image available for the user. This functionality has not changed from previous versions.

The Edit button will show Sign this section if the signature lightbox is empty. Clicking on the Edit this section clears the signature and the date. The user can sign again, if desired.

Here is an example of a standard signed section on a form when the signature property is set to Wet Signature. If the section is signed, the user can modify it by selecting the Edit this section button. The button will toggle to Sign this section and the wet signature and date in the lightbox will clear.

Clicking on the Sign this section button, displays the signature entry lightbox shown in the image below. See Signature control for details on its operation. Note that the signature image is scaled appropriately.The user will have to re-sign in order to re-lock the section.


Sections configured for wet signatures will "fall back" to using Text/Signature Image signature format if the browser you are using does not support HTML5 canvases.














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