Hashed Entity Representation

In addition to supporting ERs (entity representations, or plaintext PII strings) as input, the AbiliTec API also supports a hashed version of the ER as input. The ER string is first constructed and then the result is passed through a one-way hashing algorithm to form an opaque link that can be presented as input, but which doesn’t expose plaintext (raw) PII. ERs that have been hashed are Entity Representation Links (ERLs).

To use ERLs as input, set the lookup type parameter to the hash type used (SHA1, MD5, or SHA256).

Since ERLs are one-way hashed versions of the associated ER, requests to the API using ERLs as input only return documents when there is an exact match between the ERL and an index key for a document.

Construction of ERLs

If you're sending just email addresses as input, you can use SHA1, MD5, or SHA256 hashing to create the ERL.

If you're sending any PII other than email addresses, you must use SHA1 hashing.

ERLs are constructed by first constructing the ER as described in Entity Representation and then executing the appropriate hashing algorithm against that ER string.

For example, the SHA1 hashed version of an ER of "[email protected]" would be "89b3299ddc29491b71461060f9930d77eb767ebb".