# The Derivation Pipeline

#### Deterministic Key Generation

EtheLock does not store a random private key. It deterministically derives the key from the user's inputs. This ensures that the same card plus the same PIN always results in the same wallet.

#### The Algorithm

The derivation pipeline follows a strict, one-way mathematical function:

**1. Input Normalization**

Input = NFC\_UID\_HEX + UTF8(USER\_PIN)

**2. Hardening (Argon2id)**\
To prevent brute-force attacks, the input is passed through a memory-hard hashing function.

Entropy = Argon2id( pass=Input, salt=Protocol\_Salt, iterations=3, memory=64MB )

**3. Expansion (HKDF)**\
The entropy is expanded using HMAC-based Key Derivation Function to ensure uniform distribution suitable for elliptic curve operations.

Seed = HKDF-SHA256( ikm=Entropy, info="ethelock-v1-eth" )

**4. Key Generation**\
The resulting seed is used to generate the Ethereum key pair.

Private\_Key = secp256k1\_Project( Seed )\
Public\_Address = Keccak256( Public\_Key )


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.ethelock.xyz/5-technical-specifications/the-derivation-pipeline.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.