[Crm-sig] Fixity Hash in CRM

Simon Spero sesuncedu at gmail.com
Thu Sep 10 00:23:11 EEST 2015


Another problem with this is that a hash of a bit string does not identify
an Image (even if the hash is 1:1).

An Image is abstract and conceptual,  and has an identity is preserved
across transformations that would generate different bit strings.

Going the other way,  I believe that CIDOC does require that the same bit
string not correspond to multiple images. For example, an imaging sensor
might capture an image with the shutter closed at the start of a series of
measurements - such an image could be used for calibration.
Many such images might have identical bit strings, but would be
conceptually different works under some stances. However,  since they have
indistinguishable appearances, they are the same Image.

Fixity hashes might be better treated as properties of a FRBRoo
Manifestation; such properties are intrinsic to the Manifestation*; they
are not externally assigned in the same way that a URI, accession number,
etc are.

Simon
* or as a the value of a property that must be  the same for every item
that is an instance of that Manifestation
On Sep 9, 2015 4:15 PM, "daniel riley" <daniel at verisart.com> wrote:

> Hello all,
>
> I wanted to get confirmation on the correct application of the Cidoc-crm
> in the case of checksum hashes (i.e. fixity values).
>
> For instance if the hash of a digital image file computes to:
> 6b8dca09e851a987050463c9c60603e9ad797ba09117056fc2e0c07bcac66e43
>
> My first thought would be to use:
>
> E38_Image - P1_is_identified_by - E42_Identifier (hash value)
> E42_Identifier - P2_has_type - "SHA256 HASH"
>
> However, the scope notes for E42_Identifier explicitly states:
> The class E42 Identifier is not normally used for machine-generated
> identifiers
>
> A hash is definitely machine generated, so what are the other options
> here? Should I use a different ontology for this case?
>
> Thanks,
> Daniel Riley
> Verisart
>
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