Secure Protocol Format

Injection attacks can occur when transmitted data is not interpreted the same way by both the sender and the receiver. Guaranteeing equivalence in data interpretation, known as operational congruity, is achieved by separating fields of data on the basis of their length. When the length of the data is known, there is no risk of misinterpreting it on the basis of spaces or text delimiters. The Distinguished Encoding Rules, or DER, of the ASN.1 standard follows this approach but includes numerous constraints and, more importantly, demands that data fields to be described using binary metadata rather than text. The Secure Protocol Format, or SPF, was created as a simplified version of DER. In addition to delimiting data by length, it also affords programmers the ability to use text for describing data, just like tags are used in HTML and XML. Thus, SPF provides a simple and practical approach to preventing command injection attacks while allowing text to describe data.