When to Provide References (before or after offer)?

I haven't seen this as part of the negotiation process, generally it's just a one-time logistical issue.

I'd be ok with providing the name/relationship/contact of the reference, but clarify in a tactful way that you don't want your reference contacted until you have secured an offer (that's the norm anyway). Few other options:

• Provide the reference, but not their contact info.
• Provide a "backup" reference where it wouldn't be a big deal if they were contacted prematurely.

At the end of the day, this is an issue of trust. Presumably, if you actually may work at this company, you hopefully have enough trust with them.

@OP, generally it's after you've secured the offer, or perhaps before (for very senior positions).

Basically, it's a way for the company to validate the claims you've made on your resume, so it's done near the end of the hiring process, but not when it's all finalized.