> For the complete documentation index, see [llms.txt](https://whitepaper.zodor.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://whitepaper.zodor.io/system-architecture/overview-of-the-protocol/ecdsa.md).

# ECDSA

Securing Transactions and Validating Authenticity

The Zodor protocol uses the **Elliptic Curve Digital Signature Algorithm** to secure transactions and verify authenticity across blockchain operations. ECDSA appears at three layers:

1. **EOA signatures** for legacy compatibility
2. **ERC-4337 UserOp signing** by the smart wallet's owner key
3. **ERC-1271 contract signatures** so the smart wallet itself can sign messages (for off-chain orderbooks, login challenges, etc.)

**Core Mechanism**

1. **Signature Generation** transactions and UserOps are signed with the user's private key (held in the device Secure Enclave on mobile or a passkey on web)
2. **Public-Key Verification** the sender's public key validates the signature; the EntryPoint runs validation as part of UserOp processing
3. **Tamper Detection**  any data modification invalidates the signature

**Primary Applications**

* Transaction authorization for asset transfers
* UserOp validation in the ERC-4337 flow
* Off-chain data verification through signed messages (login, dividend claim attestations)
* Bridge message authentication (CCIP `MessageId` receipts, LayerZero OFT signatures)

**Key Benefits**

* **Authenticity**  confirms rightful account ownership
* **Data Integrity**  prevents transaction manipulation
* **Operational Security**  protects against fraud
* **Efficiency**  lightweight for scalable operations