# Two-Factor Physics

#### Independent Authentication Factors

Accessing an EtheLock wallet requires satisfying two distinct authentication factors. This prevents a single point of failure.

#### Factor 1: Possession (The Card)

* **The Physical Key:** You must physically possess the registered NFC card.
* **Anti-Cloning:** While simple NFC tags can be cloned, EtheLock binds to the unique hardware attributes of the card.
* **Remote Immunity:** A hacker in a different country cannot access your funds, regardless of how compromised your computer is, because they cannot physically tap your card against your phone.

#### Factor 2: Knowledge (The PIN)

* **The Mental Key:** You must know the 6-digit PIN chosen during setup.
* **Entropy Injection:** The PIN is not just a password; it is a mathematical ingredient ("salt") used in the key generation algorithm.
* **Theft Protection:** If your physical wallet is stolen, the thief cannot access your funds without the PIN.

#### The Combined Result

The private key is the sum of these parts.

Private Key = Function(Physical Card UID + User PIN)

If either variable is missing, the function cannot solve for the key.


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