Method and system for the verification of handwritten signatures

A computer-based method for capturing a handwritten signature that relates to a document, and thereafter verifying the handwritten signature, comprising the steps of:

• signing a document by electronically capturing a handwritten signature of a signatory;
• storing in a signature envelope a set of measurements relating to the handwritten signature;
• creating a checksum of the document;
• storing the checksum in the signature envelope;
• storing in the signature envelope a claimed identity of the signatory;
• encrypting the signature envelope to create an encrypted signature envelope;
• thereafter, decrypting the encrypted signature envelope;
• retrieving a signature template of a person having the claimed identity as stored in the signature envelope, the signature template comprising a set of measurement statistics relating to one or more genuine handwritten signatures of said person;
• and
• comparing the set of measurement statistics stored in the signature template with the set of measurements stored in the signature envelope to obtain a similarity score representative of a degree of similarity between the handwritten signature captured upon signing the document and the one or more genuine handwritten signatures.

In a computer system having a client application, a signature capture application and a signature verification application, a method for capturing and verifying an electronic representation of a handwritten signature, comprising the steps of:

• under the control of the client application,
• a. requesting that the signature capture application capture a handwritten signature;
• under the control of the signature capture application,
• b. enabling a user to electronically enter a handwritten signature,
• c. electronically capturing the handwritten signature of the user,
• d. calculating a set of measurements relating to the handwritten signature,
• e. storing the set of measurements relating to the handwritten signature in a signature envelope,
• f. storing an indication of the user's claimed identity in the signature envelope,
• g. encrypting the signature envelope to create an encrypted signature envelope, and
• h. passing the encrypted signature envelope to the client application;
• under control of the client application,
• i. passing the encrypted signature envelope to the signature verification application;
• and
• under control of the signature verification application,
• j. decrypting the encrypted signature envelope,
• k. retrieving a template comprising a set of statistical measurements corresponding to one or more genuine handwritten signatures of the user whose claimed identity is stored in the signature envelope,
• l. comparing the set of measurements stored in the signature envelope with the set of statistical measurements in the template to obtain a similarity score, and
• m. providing the similarity score to the client application.

A computer-based method for verification of a handwritten signature that relates to a document, comprising the steps of:

• providing a key;
• at the first computer processor, signing a document by electronically capturing a handwritten signature of a signatory;
• at the first computer processor, storing in a signature envelope a set of measurements relating to the handwritten signature;
• at the first computer processor, storing in the signature envelope a claimed identity of the signatory;
• at the first computer processor, using the key to create an integrity checksum of the signature envelope;
• at the first computer processor, storing the integrity checksum in the signature envelope;
• at the first computer processor, encrypting the signature envelope to create an encrypted signature envelope;
• providing the encrypted signature envelope to a second computer processor;
• providing the key to the second computer processor;
• at a second computer processor, decrypting the encrypted signature envelope;
• at the second computer processor, performing an integrity check by utilizing the key and the integrity checksum to determine if the signature envelope was modified;
• at the second computer processor, retrieving a set of statistics relating to a genuine handwritten signature of a person having the claimed identity as stored in the signature envelope;
• and
• at the second computer processor, comparing the set of statistics with the set of measurements stored in the signature envelope to obtain a similarity score.

In a computer system having a client application, a signature capture application and a signature verification application, a method for capturing and verifying an electronic representation of a handwritten signature, comprising the steps of:

• under the control of the client application,
• a. requesting that the signature capture application capture a handwritten signature, and
• b. providing a key to the signature capture application;
• under the control of the signature capture application,
• c. enabling a user to electronically enter a handwritten signature,
• d. electronically capturing the handwritten signature of the user,
• e. calculating a set of measurements relating to the handwritten signature,
• f. storing the set of measurements relating to the handwritten signature in a signature envelope,
• g. storing an indication of the user's claimed identity in the signature envelope,
• h. utilizing the key to create an integrity checksum of the signature envelope,
• i. storing the integrity checksum in the signature envelope,
• j. encrypting the signature envelope to create an encrypted signature envelope, and
• k. passing the encrypted signature envelope to the client application;
• under control of the client application,
• l. providing the encrypted signature envelope to the signature verification application, and
• m. providing the key to the signature verification application;
• under control of the signature verification application,
• n. decrypting the encrypted signature envelope,
• o. performing an integrity check by utilizing the key and the integrity checksum to determine whether the signature envelope has been modified,
• p. retrieving a template comprising a set of statistical measurements corresponding to one or more genuine handwritten signatures of the user whose claimed identity is stored in the signature envelope,
• q. comparing the set of measurements stored in the signature envelope with the set of statistical measurements in the template to obtain a similarity score,
• r. making the similarity score available to the client application, and
• s. making results of the integrity check available to the client application.

A handwritten signature authentication system comprising:

• means for displaying a gravity prompt;
• means for capturing a handwritten signature;
• means for analyzing the handwritten signature to obtain measurements relating to the handwritten signature;
• means for storing said measurements and said gravity prompt in a signature envelope;
• means for encrypting the signature envelope;
• means for decrypting the signature envelope;
• and
• means for comparing said measurements with a set of statistics of a genuine signature to obtain a similarity score.

A handwritten signature authentication system comprising:

• means for capturing a handwritten signature relating to a first document;
• means for analyzing the handwritten signature to obtain measurements relating to the handwritten signature;
• means for creating a checksum of the first document;
• means for storing said measurements and said checksum in a signature envelope;
• means for encrypting the signature envelope;
• means for decrypting the signature envelope;
• means for comparing said measurements with a set of statistics of a genuine signature to obtain a similarity score;
• and
• means for determining whether a second document is a true representation of the first document by utilizing the checksum.

A signature verification bureau system comprising:

• a plurality of first processors for capturing handwritten signatures, each one of the plurality of first processors including:
• means for electronically capturing the handwritten signature of a signatory,
• means for storing a set of measurements relating to the handwritten signature in a signature envelope,
• means for entering the signatory's claimed identity,
• means for storing the signatory's claimed identity in the signature envelope,
• means for encrypting the signature envelope to create an encrypted signature envelope, and
• means for communicating the encrypted signature envelope to a remote signature verification bureau;
• a central database for storing genuine handwritten signature data comprising a plurality of signature templates, each signature template including a set of statistical measurements;
• a signature verification bureau for verifying handwritten signatures, remotely located with respect to each of the plurality of first processors and communicating electronically therewith, the signature verification bureau controlled by a second processor and coupled to the central database, the second processor including:
• means for receiving encrypted signature envelopes from the plurality of first processors,
• means for decrypting the encrypted signature envelopes,
• means for accessing the central database to retrieve signature templates corresponding to signatory's claimed identity,
• means for verifying handwritten signatures by comparing the set of measurements stored in the signature envelope with the set of statistical measurements for the retrieved signature templates,
• means for determining similarity scores representing a similarity between the set of measurements stored in the signature envelope and the set of statistical measurements,
• means for providing the similarity score to the respective first processor.