expo-ble模块测试demo

ble/utils/CryptoUtils.ts

@@ -0,0 +1,80 @@
+import * as Crypto from 'expo-crypto';
+
+/**
+ * Cryptographic utilities for BLE communication
+ * Provides proper MD5 hashing to match Android implementation
+ */
+export class CryptoUtils {
+  /**
+   * Calculate MD5 hash of data
+   * @param data - ArrayBuffer or string to hash
+   * @returns Promise<string> - MD5 hash as hexadecimal string
+   */
+  public static async calculateMD5(data: ArrayBuffer | string): Promise<string> {
+    let dataString: string;
+    
+    if (data instanceof ArrayBuffer) {
+      // Convert ArrayBuffer to string
+      const uint8Array = new Uint8Array(data);
+      dataString = Array.from(uint8Array)
+        .map(byte => String.fromCharCode(byte))
+        .join('');
+    } else {
+      dataString = data;
+    }
+    
+    const hash = await Crypto.digestStringAsync(
+      Crypto.CryptoDigestAlgorithm.MD5,
+      dataString
+    );
+    return hash.toUpperCase();
+  }
+
+  /**
+   * Calculate MD5 hash of a file
+   * @param file - File object to hash
+   * @returns Promise<string> - MD5 hash as hexadecimal string
+   */
+  public static async calculateFileMD5(file: File): Promise<string> {
+    return new Promise((resolve, reject) => {
+      const reader = new FileReader();
+      
+      reader.onload = async (event) => {
+        try {
+          const arrayBuffer = event.target?.result as ArrayBuffer;
+          const hash = await this.calculateMD5(arrayBuffer);
+          resolve(hash);
+        } catch (error) {
+          reject(error);
+        }
+      };
+      
+      reader.onerror = () => {
+        reject(new Error('Failed to read file for MD5 calculation'));
+      };
+      
+      reader.readAsArrayBuffer(file);
+    });
+  }
+
+  /**
+   * Get partial MD5 hash (substring) to match Android implementation
+   * Android uses substring(8, 24) for file transfers
+   * @param data - Data to hash
+   * @returns Promise<string> - Partial MD5 hash
+   */
+  public static async calculatePartialMD5(data: ArrayBuffer | string): Promise<string> {
+    const fullHash = await this.calculateMD5(data);
+    return fullHash.substring(8, 24); // Match Android implementation
+  }
+
+  /**
+   * Get partial file MD5 hash
+   * @param file - File to hash
+   * @returns Promise<string> - Partial MD5 hash
+   */
+  public static async calculatePartialFileMD5(file: File): Promise<string> {
+    const fullHash = await this.calculateFileMD5(file);
+    return fullHash.substring(8, 24); // Match Android implementation
+  }
+}