15. The system of claim 14 , wherein if said comparison result is negative, the comparison module is configured to compare the plurality of characteristics extracted from the image with characteristics in the private document validation profile associated with the account.
14. The system of claim 13 , wherein a representation of a second subset of characteristics extracted from the plurality of other negotiable documents is stored in a private document validation profile associated with the account, wherein the private document validation profile is available only to the financial institution holding the account.