File security using file format validation

A method for securely validating the file format type including receiving a file having a file format type, a header and a content block. The header has a header block with a description representing attributes of the actual content in the file. The content block has leading bytes representing attributes of the actual content, and actual content. Data is parsed from the description of the header block, the leading bytes and the actual content. Data from the description is compared to the data from the leading bytes, data from the leading bytes is compared to the data from the actual content, and data from the description is compared to the data from the actual content. The file format type is validated and trustable when the data from the description, the data from the leading bytes and the data from the actual content are consistent with one another.