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UTXO Consolidation

Now let us look at one of the most damaging privacy mistakes you can make: consolidating many UTXOs into one.

From a Boltzmann entropy perspective, this is the worst possible outcome: zero entropy, zero ambiguity. If you have not yet read about Boltzmann entropy, we recommend starting with the What Is Entropy? page to understand why this matters.

UTXO consolidation transaction scanned by am-i.exposed

Transaction ID: 1b58afe9e2a9ecaebfca744ab93658d335cf010fbb32e7731e8126276820b8c1

Structure: 10 inputs → 1 output

What We Notice

This transaction takes 10 separate UTXOs and combines them into a single output. Let us look at the Boltzmann entropy analysis:

Consolidation analysis - link probability matrix

The link probability matrix shows that every single input is 100% linked to the single output. There is zero ambiguity.

Why This Is Critical

The Common Input Ownership Heuristic (CIOH) assumes that all inputs in a transaction belong to the same person. For this transaction, that assumption is almost certainly correct.

What this means: All 10 input addresses are now publicly linked together on the blockchain. If any one of those 10 addresses is ever linked to your real identity, all 10 are.

Severity: Critical

The Boltzmann Analysis Explained

The link probability matrix above shows the probability that each input funded each output. In this case:

  • There is only 1 output
  • All 10 inputs must have funded that 1 output
  • Therefore, every input is 100% linked to the output
  • Entropy = 0 bits (zero privacy)

This is the worst possible outcome for privacy. There is no ambiguity at all.

A link probability matrix answers the question: "What is the probability that input y funded output x?" for every possible pair.

For a consolidation with 10 inputs and 1 output, the matrix is simple:

Output 1
Input 1 100%
Input 2 100%
Input 3 100%
... ...
Input 10 100%

Every input is deterministically linked to the only output. There is exactly 1 valid interpretation of this transaction, so entropy = log2(1) = 0 bits.

Lesson

Never consolidate UTXOs unless they are already linked together. If you must consolidate, do it through a CoinJoin first.