Generally described, embodiments of the present invention provide a system and method for protecting a computer from malicious attacks and buffer overrun (intentional or unintentional). In particular, embodiments of the present invention protect the contents of block headers of data blocks and enable the ability for a memory manager to determine if a portion of a block header has been modified. In accordance with one aspect of the present invention, a method for securing data having a plurality of fields is provided. The method includes grouping the plurality of fields into at least a first group and a second group and generating a first identifier for the first group and a second identifier for the second group. Additionally, the first and second groups are encoded to protect the information contained in the fields of the groups. Still further, the first and second identifiers may also be encoded into the groups.