Applying a Digital Signature

Xodo PDF Studio supports both digital signatures and certified digital signatures. It's important to understand the differences between each type of digital signature prior to applying one to a PDF. In order to sign documents, you must first have a digital ID. You can either Create a New Digital ID or Import A Digital ID to be used when digitally signing documents.

Note: It's important to also understand that a digital signature is not the same as an electronic signature. An electronic signature is a graphical representation of a signature on pen and paper such as an image or drawing. A digital signature (which may also have a graphical representation) contains a unique encrypted ID to verify its authenticity.

Digital Signatures

A Digital Signature is similar to actually signing a physical document in that it identifies the person signing the document. The difference between a digital and hand written signature is that a digital signature contains encrypted information that is unique to the signer so it cannot be forged. The signer’s certificate or issuing third-party Certificate Authority will need to be trusted by the user receiving the PDF in order for the signature to be considered valid. . Once signed, if the document is modified in any way the signature will no longer be considered valid.

Certified Digital Signatures

A certified digital signature is similar in that it contains an encrypted ID unique to the signer. However, a certified signature provides additional document security options to prevent the document from being modified. The signer has the option to prevent any further changes or allow some limited changes (i.e. filling forms, adding comments, or adding digital signatures) to the document once it has been signed .

 

How to Apply a Digital Signature

A digital signature can be applied to an existing signature field or a new signature field can be created to apply a signature to a document

Applying Signature to Existing Field

  1. Click on the signature field, or click on the Digitally Sign button on the Secure Tab
    • Note: If there is more than one signature field in the document you will need to sign by clicking on the signature field
  2. This will display the Sign Document dialog. Select the Digital ID and enter the Password for the Digital ID
    • Note: If this is your first signing a document you will be asked to either import an existing ID or create a new one.
  3. Select the Digital Signature Options and Digital Signature Appearance settings that you wish to use
  4. Once complete click on Sign
  5. This will then prompt you to select a location on your computer to save the signed document
  6. Click Save to complete signing and save the document

Applying Signature When No Field Exists

  1. Click on the signature field, or click on the Digitally Sign button on the Secure Tab
  2. When the tool is started, the cursor will become a crosshair to mark the location for the new field on the document.  Drag a rectangle to create the desired signature field size
  3. After the field is created, the Sign Document dialog will be displayed. Select the Digital ID and enter the Password for the Digital ID
    • Note: If this is your first signing a document you will be asked to either import an existing ID or create a new one.
  4. Select the Digital Signature Options and Digital Signature Appearance settings that you wish to use
  5. Once complete click on Sign
  6. This will then prompt you to select a location on your computer to save the signed document
  7. Click Save to complete signing and save the document

How to Apply a Certified Digital Signature

A Certified digital signature can be applied to a document using the instructions below. When applying a certified signature without a field the signature can be either visible or invisible. Invisible signatures are stored using the same encryption only there is no visual representation of the signature on any of the document's pages.

Applying a Certified Signature to Existing Field

  1. Click on the signature field, or click on the Certify Document button on the Secure Tab
    • Note: If there is more than one signature field in the document you will need to sign by clicking on the signature field
  2. This will display the Sign Document dialog. Select the Digital ID and enter the Password for the Digital ID
    • Note: If this is your first signing a document you will be asked to either import an existing ID or create a new one.
  3. Choose the Digital Signature Options and Digital Signature Appearance settings that you wish to use
    • Note: Make sure that "Certifying Signature" is selected for the signature Type
  4. Select the certifying signature permissions from the drop down
  5. Once complete click on Sign
  6. This will then prompt you to select a location on your computer to save the signed document
  7. Click Save to complete signing and save the document

Applying a Certified Signature When No Field Exists

  1. Click on the signature field, or click on the Certify Document button on the Secure Tab and choose Visible
  2. When the tool is started, the cursor will become a crosshair to mark the location for the new field on the document.  Drag a rectangle to create the desired signature field size
  3. After the field is created, the Sign Document dialog will be displayed. Select the Digital ID and enter the Password for the Digital ID
    • Note: If this is your first signing a document you will be asked to either import an existing ID or create a new one.
  4. Select the Digital Signature Options and Digital Signature Appearance settings that you wish to use
    • Note: Make sure that "Certifying Signature" is selected for the signature Type
  5. Select the certifying signature permissions from the drop down
  6. Once complete click on Sign
  7. This will then prompt you to select a location on your computer to save the signed document
  8. Click Save to complete signing and save the document

Applying an Invisible Certified Digital Signature

  1. Click on the signature field, or click on the Certify Document button on the Secure Tab and choose Invisible
  2. The Sign Document dialog will be displayed. Select the Digital ID and enter the Password for the Digital ID
    • Note: If this is your first signing a document you will be asked to either import an existing ID or create a new one.
  3. Select the Digital Signature Options and Digital Signature Appearance settings that you wish to use
    • Note: Make sure that "Certifying Signature" is selected for the signature Type
  4. Select the certifying signature permissions from the drop down
  5. Once complete click on Sign
  6. This will then prompt you to select a location on your computer to save the signed document
  7. Click Save to complete signing and save the document