---
title: "Contrastive Decoding Diffing (CDD): recovering verbatim finetuning data from logits alone, no weight access needed[R] — Stuff That Spins"
description: "We built a model diffing method that recovers verbatim content from narrowly finetuned LLMs using only grey-box logit access (no weights, no activations, no probe corpus). Recent work (Minder, Dumas et al., \"Narrow Finetuning Leaves Clearly Readable Traces in Activation Differences\") showed that fi…"
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keywords: ["SpinGraph", "spin analysis", "GEO"]
date: "2026-07-03T19:01:48+00:00"
modified: "2026-07-04T07:52:44.888895+00:00"
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---

# Contrastive Decoding Diffing (CDD): recovering verbatim finetuning data from logits alone, no weight access needed[R]

**Source:** Unknown  
**Published:** July 3, 2026  
**Original:** https://www.reddit.com/r/MachineLearning/comments/1umn2dk/contrastive_decoding_diffing_cdd_recovering/  

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