An
encryption-free technique for enabling the self-
authentication of value documents (including personal and commercial checks) presented at a point of purchase or financial institution. Certain data contained on the value document may be signed with a first
digital signature and authenticated with a
public key certificate issued from a trusted
certificate authority. The signed data and
public key certificate are stored on the value document, preferably in a two-dimensional bar code
data format. In the case of certain personal value documents (such as checks, credit cards, passports, birth certificates, Social Security cards, etc.), a unique
personal identification number (PIN) also may be included in the document data that is signed by a second
digital signature. At a point of purchase, a merchant or teller can scan and read the data stored in the two-dimensional bar code and other magnetically recorded information, and together with the PIN the customer provides, can authenticate the value document thus presented using the second
digital signature. Alternatively, if the customer is not present, if the personal value document contains the second digital signature, the document may be verified using a PIN-generating
algorithm or other method that generates all permutations of PINs. The first digital signature alone may be used to authenticate selected data within the personal value document even when the PIN is not available. Similarly, in the case of a commercial value documents,
authentication of pre-printed data may be based entirely upon only the first digital signature.