# ECDHAlgorithmiOS

**Repository Path**: morgan031/ECDHAlgorithmiOS

## Basic Information

- **Project Name**: ECDHAlgorithmiOS
- **Description**: 一种基于椭圆曲线密码学的OC密钥交换协议算法开源项目。
An open-source project for OC key exchange protocol algorithm based on elliptic curve cryptography.
- **Primary Language**: Objective-C
- **License**: MIT
- **Default Branch**: main
- **Homepage**: None
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 0
- **Created**: 2025-08-19
- **Last Updated**: 2025-08-21

## Categories & Tags

**Categories**: Uncategorized

**Tags**: Objective-c, ECDH, gmellipticcurvecrypto

## README

<h1 align="center"><a href="https://github.com/Json031/ECDHAlgorithmSwift"><img src="https://img.shields.io/badge/swift-5.0-orange?logo=swift" title="Swift version" float=left></a><strong><a href="https://github.com/Json031/ECDHAlgorithmSwift">Click here to go to the Swift version</a></strong></h1>

# ECDHAlgorithmiOS
[![CocoaPods](https://img.shields.io/cocoapods/v/ECDHAlgorithmiOS.svg)](https://cocoapods.org/pods/ECDHAlgorithmiOS)
[![License](https://img.shields.io/badge/license-MIT-brightgreen.svg)](https://github.com/Json031/ECDHAlgorithmiOS/blob/main/LICENSE)
<br>
一种基于椭圆曲线密码学的OC密钥交换协议算法开源项目。
<br>An open-source project for OC key exchange protocol algorithm based on elliptic curve cryptography.

# Installation 安装:

## CocoaPods
The [ECDHAlgorithmiOS SDK for iOS](https://github.com/Json031/ECDHAlgorithmiOS) is available through [CocoaPods](http://cocoapods.org). If CocoaPods is not installed, install it using the following command. Note that Ruby will also be installed, as it is a dependency of Cocoapods.
   ```bash
   brew install cocoapods
   pod setup
   ```
   ```bash
   $iOSVersion = '11.0'
   
   platform :ios, $iOSVersion
   use_frameworks!
   
   target 'YourProjectName' do
         pod 'ECDHAlgorithmiOS' # Full version with all features
   end
   ```

## 手动安装
将Classes文件夹拽入项目中，导入头文件：#import "ECDHAlgorithmiOS.h"

## ECDH算法

ECDH非对称加密方式交换对称密钥流程：
<br>1️⃣调用方法generateKeys生成密钥对(公钥64字节和私钥32字节)
<br>2️⃣通过蓝牙或http方式，将步骤1️⃣生成的公钥发给对方
<br>3️⃣等待对方蓝牙Notify等方式发送它的公钥过来，调用configThirdPublicKey将对方的公钥和自己的私钥生成share key，对方也通过步骤2️⃣接收到的公钥与其私钥生成share key，根据椭圆曲线点乘的交换性原理这两个share key是一样的
<br>4️⃣将共享密钥发送到后端服务器，如果后端服务器验证两者相同，则表示身份验证成功；
<br>可用于双方身份验证及绑定关联；
<br>还可以作为后续通信过程的数据对称加密算法的密钥，基于椭圆曲线离散对数问题的困难性，使得攻击者难以从公开的通信信息中获取共享密钥，确保了通信数据安全性；

The process of exchanging symmetric keys using ECDH asymmetric encryption method:
<br>1 Call method generateKeys to generate a key pair (64 bytes for public key and 32 bytes for private key).
<br>2 Call the sendPublicKey method to convert step 2 Send the public key to the other party.
<br>3 Wait for the other party to notify and send its public key, call configThirdPublicKey to generate a share key from the other party's public key and its own private key, and the other party also uses step 3 The received public key and its private key generate a share key, and the two share keys are the same.
<br>4 Send the share key to the backend server, and if the backend server verifies that both are the same, it indicates successful authentication.
<br>Can be used for mutual authentication and binding association;
<br>It can also serve as a key for data symmetric encryption algorithms in subsequent communication processes to ensure the security of communication data;

# ECDH asymmetric encryption example:
✳️Param: set compressedPublicKey = false

1️⃣GMEllipticCurveCrypto1 generateKeyPair:
<br>publicKey1: "d4b78cec17668f06ae96943d71049c7f75a620cb50b6facff9bdb09a174f7a808c22f0e51f1b2578e9fd7682be17fb8e07deb6517b68880273baee7fc4d6efdd"
<br>privateKey1: "jCfYOOEE+t2BHvUHjp1O0RObXhND7JLV9BaHGR1XDZE="

2️⃣GMEllipticCurveCrypto2 generateKeyPair:
<br>publicKey2: "79cff9b55e086234c43f5c64a775eb20f39c7dc11bf3b2962677d6019c42af5cf57d6d5007fa7ccc94bddec7b1b8fdbf68e50642de88b7223e40007602290e50"
<br>privateKey2: "ISfGAyQrHKX4ELRoZLls3TqBXVf7yqoahEgj7RMX0Us="

3️⃣generateSharedKeyWithOtherPK
<br>sharedKey1 = GMEllipticCurveCrypto1.sharedSecret(forPublicKey: publicKey2)
<br>sharedKey2 = GMEllipticCurveCrypto2.sharedSecret(forPublicKey: publicKey1)

✅Result: sharedKey1 should equal to sharedKey2
<br>sharedKey1: "2fd727d984828a28ab6a521f53dd2d06c67fbb80104aef8c1369a9e352094424"
<br>sharedKey2: "2fd727d984828a28ab6a521f53dd2d06c67fbb80104aef8c1369a9e352094424"

# Troubleshooting

<details>
  <summary><code>Missing sharedKey，Please obtain the public key from a third party first, and then pass it to the sharedScreetForPublicKey method of GMEllipticCurveCrypto to generate the share key</code></summary>

Need to obtain the public key from a third party first, then go to generateSharedKeyWithOtherPK.

</details>

<br>

# License
This library is licensed under the [MIT License](https://github.com/Json031/ECDHAlgorithmiOS/blob/main/LICENSE).