Patent ID: 8621223

Claim:
A method of verifying integrity of a digital file comprising: labeling, in a first network, the digital file prior to exposure to a foreign environment, the first network having a first security classification level, wherein labeling comprises: creating a header label comprising an identification of the first security classification level; appending the header label to the digital file; hashing the digital file, together with the appended header label, to obtain a first hash value; signing the first hash value to create a digital signature; creating a signature label comprising one or both of the first hash value and the digital signature; and appending the signature label to the digital file; and validating, in a second network, the digital file subsequent to exposure to the foreign environment, the second network having a second security classification level that is different from the first security classification level, wherein validating comprises: hashing the digital file to obtain a second hash value; retrieving the first hash value from the signature label; comparing the first hash value and second hash value; and removing the signature label from the digital file.