完善细节

src/App.tsx

@@ -260,16 +260,6 @@ function App() {
           <h2>Hex / UTF8 转换</h2>
           
           <div style={{ display: 'flex', gap: '1rem', marginBottom: '1rem' }}>
-            <div className="form-group" style={{ flex: 1 }}>
-              <label>Hex 输入</label>
-              <textarea 
-                value={hexInput} 
-                onChange={(e) => setHexInput(e.target.value)}
-                placeholder="输入 hex 字符串"
-                style={{ height: '200px' }}
-              />
-            </div>
-            
             <div className="form-group" style={{ flex: 1 }}>
               <label>UTF8 输入</label>
               <textarea 
@@ -278,15 +268,28 @@ function App() {
                 placeholder="输入 UTF8 字符串"
                 style={{ height: '200px' }}
               />
+              <button onClick={handleUtf8ToHex} style={{ marginTop: '0.5rem' }}>UTF8 → Hex</button>
+            </div>
+            
+            <div className="form-group" style={{ flex: 1 }}>
+              <label>Hex 输入</label>
+              <textarea 
+                value={hexInput} 
+                onChange={(e) => setHexInput(e.target.value)}
+                placeholder="输入 hex 字符串"
+                style={{ height: '200px' }}
+              />
+              <button onClick={handleHexToUtf8} style={{ marginTop: '0.5rem' }}>UTF8 ← Hex</button>
             </div>
-          </div>
-          
-          <div className="button-group">
-            <button onClick={handleHexToUtf8}>Hex → UTF8</button>
-            <button onClick={handleUtf8ToHex}>UTF8 → Hex</button>
           </div>
         </div>
       )}
+      
+      {/* 页脚 */}
+      <footer style={{ marginTop: '2rem', padding: '1rem', borderTop: '1px solid #ccc', textAlign: 'center' }}>
+        <p>© 2026 安全算法计算工具</p>
+        <p>版本号: V1.0-{new Date().toISOString().slice(0, 19).replace(/[-:T]/g, '')}</p>
+      </footer>
     </div>
   )
 }

src/utils/algorithm/sm4.ts

@@ -82,10 +82,9 @@ export const sm4Encrypt = (message: string, key: string, mode: string, iv?: stri
   if (modeLower === 'ecb') {
     // ECB 模式使用 gm-crypto
     return SM4.encrypt(message, key, {
-      mode: 'ecb',
+      mode: SM4.constants.ECB,
       inputEncoding: 'hex',
-      outputEncoding: 'hex',
-      padding: paddingMode === 'pkcs7' ? 'pkcs7' : 'none'
+      outputEncoding: 'hex'
     })
   } else if (modeLower === 'cbc') {
     // CBC 模式使用 gmsm-sm4js
@@ -116,6 +115,10 @@ export const sm4Encrypt = (message: string, key: string, mode: string, iv?: stri
     if (!iv) {
       throw new Error('IV is required for GCM mode')
     }
+    // 检查 IV 长度是否为 12 个字节
+    if (iv.length !== 24) { // 12 字节的 hex 字符串长度为 24
+      throw new Error('IV length must be 12 bytes (24 hex characters) for GCM mode')
+    }
     // 转换为字节数组
     const messageBytes = hexToBytes(message)
     const keyBytes = hexToBytes(key)
@@ -176,10 +179,9 @@ export const sm4Decrypt = (encrypted: string, key: string, mode: string, iv?: st
   if (modeLower === 'ecb') {
     // ECB 模式使用 gm-crypto
     return SM4.decrypt(encrypted, key, {
-      mode: 'ecb',
+      mode: SM4.constants.ECB,
       inputEncoding: 'hex',
-      outputEncoding: 'hex',
-      padding: paddingMode === 'pkcs7' ? 'pkcs7' : 'none'
+      outputEncoding: 'hex'
     })
   } else if (modeLower === 'cbc') {
     // CBC 模式使用 gmsm-sm4js
@@ -208,6 +210,10 @@ export const sm4Decrypt = (encrypted: string, key: string, mode: string, iv?: st
     if (!iv) {
       throw new Error('IV is required for GCM mode')
     }
+    // 检查 IV 长度是否为 12 个字节
+    if (iv.length !== 24) { // 12 字节的 hex 字符串长度为 24
+      throw new Error('IV length must be 12 bytes (24 hex characters) for GCM mode')
+    }
     // 转换为字节数组
     const encryptedBytes = hexToBytes(encrypted)
     const keyBytes = hexToBytes(key)