A traditional holographic signature affixes a distinctive mark to the original document (the signature) that may be used as evidence that the signing party approved or authorized the document. An electronic signature calls for a similar outcome; some distinctive mark must be affixed to the original document as evidence of the electronic signature. This outcome has been articulated in the NMFS policy directive 32-110 as "...tie the electronic transaction to the individual or entity in a legally-binding way." In technical literature the process to achieve this outcome is frequently referred to as "Binding Document to Identity".
In evaluating alternative approaches to binding document to identity, it is sometimes helpful to distinguish two different concerns; non-repudiation and integrity. Non-repudiation refers to limiting the ability of the signer to repudiate, or deny responsibility, for the signature. Integrity refers to confidence that the signed document has not been altered subsequent to the signature.
To address non-repudiation concerns an association must be made between the electronic document and some distinctive item of data that identifies the signing party, in a way that makes the signature attributable to the signing party. To address integrity concerns the document and the association to the signing party must be stored and retrieved in such a way that any alteration in either would be detected; i.e., the storage and retrieval must be tamper evident.