Systems and methods for determining a character sequence digest. An example method may comprise: identifying, within a character sequence, one or more sections, wherein each section comprises a section header and one or more section bodies; performing the following operations for each identified section body: responsive to determining that the section body is not preceded by a section header, prepending a section header to the section body; calculating a section digest by applying a hash function to the section comprising the section header and the section body; and calculating a digest of the character sequence by applying a symmetric summing operation to one or more section digests.