b'(b) De-Identified InformationIf information relates to the representation of a client, but there is no reasonable likelihood that it could be used to ascertain the identity of the client or matter, we classify this asDe-Identified Information . This includes true hypotheticals and other scenarios that satisfy Rule 1.6, Comment [4], which permits discussion so long as the listener could not reasonably identify the client or matter. 22When evaluating whether there is a reasonable likelihood that information could be used to ascertain the identity of a client or matter, lawyers should bear in mind that artificial intelligence systems are exceptionally good at detecting patterns and correlations that may allow reidentification of information that appears anonymous to a human. 23Accordingly, lawyers are encouraged to consider more formal methods of creating De-Identified Information, particularly in sensitive matters. 24This concern extends beyond direct data entry into GAI tools, because these systems are frequently trained on data scraped from the internet. Similar re-identification risks can arise when lawyers post hypotheticals or case summaries in public forums, blogs, or listservs. In short, while De-Identified Information carries less risk than identifiable client information, it is not risk-free and should still be managed appropriately when processed by a GAI tool. (c) Confidential InformationFor purposes of this Guide,Confidential Informationmeans information that is protected by Rule 1.6, or is otherwise subject to confidentiality obligations, but does not contain Sensitive Personal Information as defined below. Confidential Information includes information that relates to the representation of a client that could reasonably be used to identify the client or the situation involved, even if direct identifiers are omitted. (d) Sensitive Personal InformationForpurposesofthisGuide,webelievethatsometypesofConfidentialInformationmeritadditional protection. In our view, Illinois public policy calls for information that is specifically listed in the Illinois Personal Information Protection Act to be granted additional safeguards. 25 This includes: o Social Security numbers and tax returnso Drivers license numbers or state identification card numberso Account, credit card, or debit card numberso Medical information, including mental health and substance abuse treatment recordso Health insurance information22Ill. R. Profl Conduct R. 1.6 cmt. 4 (2025). 23John X. Morris et al.,DIRI: Adversarial Patient Reidentification with Large Language Models for Evaluating Clinical .g., , AMIA Jt. Summits Transl. Sci. Proc. (2025). Te xt A, nony Um.Siz. aDteiopnt of Health & Human Servs.,Guidance Regarding Methods for De-Identification of Protected Health 24Information in Accordance with the Health Insurance Portability and Accountability Act (HIPAA) Privacy Rule(Nov. 26, 20S1e2e).e 25815 ILCS 530/5.Page | 8'