Natural Visualization And Routing Of Digital Signatures

Abstract

Embodiments are provided for securely visualizing and routing digital signatures in an electronic document generated by an application program executing on a computer system. The application program may generate an electronic document for receiving a signature graphic, and calculate a hash value from the electronic document and the signature graphic, and create a cryptographic signature from the hash value using a cryptographic encryption method. The electronic document is digitally signed by embedding the cryptographic signature therein. The application program may further collect and route digital signatures by automatically collecting signatures from individual signers, one-by-one, and identify the appropriate signature line for each signer to sign. The application program may further generate a user interface for creating and collecting digital signatures.

1 . A computer-implemented method for securely visualizing digital signatures in an electronic document generated by an application program executing on a computer system, comprising:
 receiving, in the electronic document, at least one signature graphic;   calculating a hash value from the electronic document including the at least one signature graphic;   generating a digital signature object comprising the hash value and cryptographic data, the digital signature object comprising a cryptographic signature;   embedding the digital signature object in the electronic document; and   displaying the electronic document comprising the at least one signature graphic and the digital signature object as a digital signature.   
   
   
       2 . The method of  claim 1 , wherein receiving at least one signature graphic comprises receiving a signature graphic file stored in the computer system. 
   
   
       3 . The method of  claim 1 , wherein receiving at least one signature graphic comprises receiving at least one typed character in a signature font in the user interface from a user. 
   
   
       4 . The method of  claim 1 , wherein receiving at least one signature graphic comprises, in substantially real-time, a handwritten signature from a user. 
   
   
       5 . The method of  claim 1 , wherein receiving, in the electronic document, at least one signature graphic comprises receiving a signature in at least one of a Western signature format and an Eastern signature format. 
   
   
       6 . The method of  claim 1 , wherein generating a digital signature object comprising the hash value and cryptographic data comprises:
 encrypting the hash value using private key cryptographic data; and   adding one or more of the following to the encrypted hash value: digital certificate cryptographic data and public key cryptographic data.   
   
   
       7 . The method of  claim 1  further comprising:
 prior to calculating the hash value, determining whether the at least one signature graphic is in a compatible graphic file format; and   if it is determined that the at least one signature graphic is not in a compatible graphic file format, then converting the at least one signature graphic into the compatible graphic file format.   
   
   
       8 . The method of  claim 1  further comprising:
 comparing a new hash value calculated from the electronic document and the signature graphic to the hash value in the digital signature object;   if the compared hash values match, then validating the digital signature; and   if the compared hash values do not match, then invalidating the digital signature.   
   
   
       9 . A computer-implemented method for collecting digital signatures for routing through an application program executing on a computer system, comprising:
 (a) sending a link to an electronic document to only one current signer identified by an unsigned signature line among a plurality of signature lines for receiving a digital signature, wherein the electronic document is generated by the application program;   (b) automatically selecting, from among the plurality of signature lines, the unsigned signature line for receiving the digital signature from the current signer,   (c) receiving the digital signature of the current signer in the selected unsigned signature line;   (d) upon receiving the digital signature of the current signer, repeating the operations (a)-(c) for each of the plurality of signature lines in the electronic document until digital signatures have been received for each of the plurality of signature lines.   
   
   
       10 . The method of  claim 9  further comprising, prior to sending the link to the electronic document, receiving metadata for appending to each of the plurality of signature lines in the electronic document, the metadata comprising one or more of the following identifiers: a signer name, an electronic mail address of the signer, and a title of the signer. 
   
   
       11 . The method of  claim 10 , wherein automatically selecting the unsigned signature line for receiving the digital signature from the current signer comprises:
 selecting an identifier contained within the metadata for each of the plurality of signature lines in the electronic document; and   selecting a signature line from among the plurality of signature lines having an identifier which matches at least one of an electronic mail address or a title determined for the current signer as the unsigned signature line for receiving the digital signature from the current signer.   
   
   
       12 . The method of  claim 9 , prior to sending the link to the electronic document, further comprising:
 converting the electronic document into a tree comprising a plurality of markup language nodes containing the plurality of signature lines, the tree representing a visual layout of the plurality of signature lines in the electronic document;   traversing the markup language nodes to determine a visual order of each of the plurality of signature lines; and   assigning a number to each of the plurality of markup language nodes corresponding to the visual order.   
   
   
       13 . The method of  claim 12 , wherein assigning a number to each of the plurality of markup language nodes corresponding to the visual order comprises assigning each number to the plurality of markup language nodes in at least one of a left-to-right visual order and a right-to-left visual order. 
   
   
       14 . The method of  claim 12 , wherein automatically selecting the unsigned signature line for receiving the digital signature from the current signer comprises:
 traversing the visual layout of the plurality of signature lines in the electronic document for previously received digital signatures; and   selecting the first unsigned signature line as the unsigned signature line for receiving the digital signature from the current signer.   
   
   
       15 . A computer-readable storage medium comprising computer executable instructions which, when executed on a computer, will cause the computer to perform a method of displaying on a display device a user interface for generating and validating signature data for securely visualizing digital signatures in an electronic document, the method comprising:
 displaying a first window for receiving a signature graphic associated with a signer of the electronic document;   displaying the received signature graphic in the first window;   validating the received signature graphic against a digital signature object embedded in the electronic document;   displaying a second window for defining the display of a plurality of signature line properties for at least one signature line displayed in the electronic document, the signature line properties comprising:
 signature data comprising one or more of the following:
 a name of the signer of the electronic document; 
 a title of the signer of the electronic document; and 
 an electronic mail address associated with the signer of the electronic document; 
 
 appearance options for displaying the signature graphic in the electronic document, the appearance options comprising one or more of the following:
 a first option for displaying the signature graphic over the at least one signature line; 
 a second option for displaying the signature graphic as a stamp when the signature graphic comprises an Eastern signature format; and 
 a third option for displaying a date that the electronic document was signed; and 
 
 displaying a third window for defining a plurality of signature properties for the electronic document, the signature properties comprising one or more of the following selectable options:
 a first option for signing the entire electronic document; 
 a second option for signing one or more identified portions of the electronic document; 
 a third option for co-signing a plurality of signature lines in the electronic document; and 
 a fourth option for counter-signing a plurality of signatures lines in the electronic document. 
 
   
   
   
       16 . The computer-readable storage medium of  claim 15 , wherein receiving a signature graphic comprises receiving a signature graphic file stored in the computer. 
   
   
       17 . The computer-readable storage medium of  claim 15 , wherein receiving a signature graphic comprises receiving at least one typed character in a typographical font. 
   
   
       18 . The computer-readable storage medium of  claim 15 , wherein receiving a signature graphic comprises receiving a signature graphic in at least one of a Western signature format and an Eastern signature format. 
   
   
       19 . The computer-readable medium of  claim 15 , wherein the digital signature object embedded in the electronic document comprises an encrypted hash value generated from the electronic document, the signature graphic, and private key cryptographic data, wherein the encrypted hash value is summed with digital certificate cryptographic data and public key cryptographic data to generate the digital signature object. 
   
   
       20 . The computer-readable medium of  claim 15 , wherein the identified portions of the electronic document comprise one or more of the following: received user-named data in the electronic document, received user-identified fields and groups in the electronic document, and a received user group name for storing digital signatures received in the electronic document.