6.6.2 Integrity in On Line and Off Line Access Environments  Prior to the existence of remote access in the online environment, such things as authenticity and integrity were established by individuals in the reading rooms and listening posts of the collecting institutions. The content was delivered by representatives of institutions whose reputation spoke for the integrity of the content. Original materials could be retrieved for examination if the copies were questioned.  The online environment still relies to some extent on the trusted nature of the collecting institution, however, an unambiguously original item can never be provided online, and the possibility of undetected tampering or accidental corruption exists within the archive and distribution network. To counter this, various systems exist which mathematically attest to the authenticity or integrity of an item or work.  Authenticity is a concern with knowing that something has originated from a particular source. The trusted nature of the institution creating the content attests to the processes, and a certificate authority is issued which a third party can use as a guarantee of authenticity.Various systems exist and are valuable where this could be an issue.  Integrity refers to a wish to know whether an item has been damaged or tampered with. Checksums represent the common way of dealing with integrity, and are valuable tools in both the archive and the distribution network (see 6.3.23 Integrity and Check sums). However, as is discussed in 6.3.23, checksums are fallible, and their use requires monitoring on behalf of the archive of latest developments.