# The Four Epochs of Privacy

To understand FOGEVM, one must understand the trajectory of cryptographic privacy:

1. **Epoch 1: Obfuscation**

* **Example:** Dash.
* **Method:** CoinJoin and mixing services.
* **Limitation:** Privacy was optional and statistical. Sophisticated chain analysis could often trace "mixed" coins back to their origin.

2. **Epoch 2: The Shield**

* Example: Zcash.
* Method: zk-SNARKs (Zero-Knowledge Succinct Non-Interactive Arguments of Knowledge).
* Limitation: While mathematically secure, these chains lacked programmability. They were isolated silos of value, unable to support complex DeFi applications.

3. **Epoch 3: The Ring**

* Example: Monero.
* Method: Ring Signatures and Stealth Addresses.
* Limitation: Severe scalability constraints and a lack of smart contract compatibility.

4. **Epoch 4: The Fog**

* Method: **Encrypted EVM Execution.**
* Innovation: We do not force users to choose between privacy and utility. By forking the Geth client and wrapping the runtime in a privacy layer, we allow standard Solidity contracts to inherit privacy properties automatically.


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