Patent ID: 7246309

Claim:
A system for validating one or more data blocks in a document derived from another document, comprising one or more processors collectively operable to: access a plurality of first values in a predetermined portion of a source document; apply a code-generating algorithm to the first values in the predetermined portion of the source document to generate a first code representing the first values in the predetermined portion of the source document; access a plurality of second values in a predetermined portion of a document derived from the source document, the predetermined portion of the derived document corresponding to the predetermined portion of the source document; and apply the code-generating algorithm to the second values in the predetermined portion of the derived document to generate a second code representing the second values in the predetermined portion of the derived document; where, if the first code representing the first values in the predetermined portion of the source document matches the second code representing the second values in the predetermined portion of the derived document, it can be assumed that within a predefined probability the derived document was accurately derived from the source document in that the second values in the predetermined portion of the derived document match the first values in the predetermined portion of the source document; wherein: the first values in the predetermined portion of the source document and second values in the predetermined portion of the derived document comprise only numerical digits; the first code generated through application of the code-generating algorithm to the first values in the predetermined portion of the source document and the second code generated through application of the code-generating algorithm to the second values in the predetermined portion of the derived document each comprise only alphabetic characters; and the code-generating algorithm comprises: calculating a weighted sum of the numerical digits of the first values in the predetermined portion of the source document; applying a modulus(p) to the weighted sum to determine a result, p being a prime number; calculating a complement of the modulus(p) as a check-digit; and converting the determined result and the check-digit into alphabetic characters.