diff --git a/app/src/main/java/io/legado/app/help/JsExtensions.kt b/app/src/main/java/io/legado/app/help/JsExtensions.kt
index 53feb4054..64d8d0893 100644
--- a/app/src/main/java/io/legado/app/help/JsExtensions.kt
+++ b/app/src/main/java/io/legado/app/help/JsExtensions.kt
@@ -338,4 +338,149 @@ interface JsExtensions {
         Debug.log(msg)
         return msg
     }
+
+    /**
+     * AES 解码为 ByteArray
+     * @param str 传入的AES加密的数据
+     * @param key AES 解密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+    fun aesDecodeToByteArray(
+        str: String,
+        key: String,
+        transformation: String,
+        iv: String = ""
+    ): ByteArray? {
+
+        return EncoderUtils.decryptAES(
+            data = str.encodeToByteArray(),
+            key = key.encodeToByteArray(),
+            transformation,
+            iv.encodeToByteArray()
+        )
+    }
+
+    /**
+     * AES 解码为 String
+     * @param str 传入的AES加密的数据
+     * @param key AES 解密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+
+    fun aesDecodeToString(
+        str: String,
+        key: String,
+        transformation: String,
+        iv: String = ""
+    ): String? {
+        return aesDecodeToByteArray(str, key, transformation, iv)?.let { String(it) }
+    }
+
+    /**
+     * 已经base64的AES 解码为 ByteArray
+     * @param str 传入的AES Base64加密的数据
+     * @param key AES 解密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+
+    fun aesBase64DecodeToByteArray(
+        str: String,
+        key: String,
+        transformation: String,
+        iv: String = ""
+    ): ByteArray? {
+        return EncoderUtils.decryptBase64AES(
+            data = str.encodeToByteArray(),
+            key = key.encodeToByteArray(),
+            transformation,
+            iv.encodeToByteArray()
+        )
+    }
+
+    /**
+     * 已经base64的AES 解码为 String
+     * @param str 传入的AES Base64加密的数据
+     * @param key AES 解密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+
+    fun aesBase64DecodeToString(
+        str: String,
+        key: String,
+        transformation: String,
+        iv: String = ""
+    ): String? {
+        return aesBase64DecodeToByteArray(str, key, transformation, iv)?.let { String(it) }
+    }
+
+    /**
+     * 加密aes为ByteArray
+     * @param data 传入的原始数据
+     * @param key AES加密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+    fun aesEncodeToByteArray(
+        data: String, key: String, transformation: String,
+        iv: String = ""
+    ): ByteArray? {
+        return EncoderUtils.encryptAES(
+            data.encodeToByteArray(),
+            key = key.encodeToByteArray(),
+            transformation,
+            iv.encodeToByteArray()
+        )
+    }
+
+    /**
+     * 加密aes为String
+     * @param data 传入的原始数据
+     * @param key AES加密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+    fun aesEncodeToString(
+        data: String, key: String, transformation: String,
+        iv: String = ""
+    ): String? {
+        return aesEncodeToByteArray(data, key, transformation, iv)?.let { String(it) }
+    }
+
+    /**
+     * 加密aes后Base64化的ByteArray
+     * @param data 传入的原始数据
+     * @param key AES加密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+    fun aesEncodeToBase64ByteArray(
+        data: String, key: String, transformation: String,
+        iv: String = ""
+    ): ByteArray? {
+        return EncoderUtils.encryptAES2Base64(
+            data.encodeToByteArray(),
+            key = key.encodeToByteArray(),
+            transformation,
+            iv.encodeToByteArray()
+        )
+    }
+
+    /**
+     * 加密aes后Base64化的String
+     * @param data 传入的原始数据
+     * @param key AES加密的key
+     * @param transformation AES加密的方式
+     * @param iv ECB模式的偏移向量
+     */
+    fun aesEncodeToBase64String(
+        data: String, key: String, transformation: String,
+        iv: String = ""
+    ): String? {
+        return aesEncodeToBase64ByteArray(data, key, transformation, iv)?.let { String(it) }
+    }
+
 }
diff --git a/app/src/main/java/io/legado/app/ui/book/cache/CacheViewModel.kt b/app/src/main/java/io/legado/app/ui/book/cache/CacheViewModel.kt
index b40fb07cd..4554c094a 100644
--- a/app/src/main/java/io/legado/app/ui/book/cache/CacheViewModel.kt
+++ b/app/src/main/java/io/legado/app/ui/book/cache/CacheViewModel.kt
@@ -207,7 +207,7 @@ class CacheViewModel(application: Application) : BaseViewModel(application) {
         //set css
         epubBook.resources.add(
             Resource(
-                "body,div{background:white;margin:0 auto;padding:0;outline:none;width:100%;}h2{color:#005a9c;text-align:left;}p{text-indent:2em;text-align:justify;}img{display:inline-block;width:100%;height:100%;max-width: 100%;max-height:100%;}".encodeToByteArray(),
+                "body,div{background:white;outline:none;width:100%;}h2{color:#005a9c;text-align:left;}p{text-indent:2em;text-align:justify;}img{display:inline-block;width:100%;height:auto;max-width: 100%;max-height:100%;}".encodeToByteArray(),
                 "css/style.css"
             )
         )
diff --git a/app/src/main/java/io/legado/app/utils/EncoderUtils.kt b/app/src/main/java/io/legado/app/utils/EncoderUtils.kt
index 409cb802c..976f1c1be 100644
--- a/app/src/main/java/io/legado/app/utils/EncoderUtils.kt
+++ b/app/src/main/java/io/legado/app/utils/EncoderUtils.kt
@@ -1,6 +1,10 @@
 package io.legado.app.utils
 
 import android.util.Base64
+import java.security.spec.AlgorithmParameterSpec
+import javax.crypto.Cipher
+import javax.crypto.spec.IvParameterSpec
+import javax.crypto.spec.SecretKeySpec
 
 @Suppress("unused")
 object EncoderUtils {
@@ -34,4 +38,124 @@ object EncoderUtils {
     fun base64Encode(str: String, flags: Int = Base64.NO_WRAP): String? {
         return Base64.encodeToString(str.toByteArray(), flags)
     }
+    //////////AES Start
+
+    /**
+     * Return the Base64-encode bytes of AES encryption.
+     *
+     * @param data           The data.
+     * @param key            The key.
+     * @param transformation The name of the transformation, e.g., *DES/CBC/PKCS5Padding*.
+     * @param iv             The buffer with the IV. The contents of the
+     * buffer are copied to protect against subsequent modification.
+     * @return the Base64-encode bytes of AES encryption
+     */
+    fun encryptAES2Base64(
+        data: ByteArray?,
+        key: ByteArray?,
+        transformation: String?,
+        iv: ByteArray?
+    ): ByteArray? {
+        return Base64.encode(encryptAES(data, key, transformation, iv), Base64.NO_WRAP)
+    }
+
+    /**
+     * Return the bytes of AES encryption.
+     *
+     * @param data           The data.
+     * @param key            The key.
+     * @param transformation The name of the transformation, e.g., *DES/CBC/PKCS5Padding*.
+     * @param iv             The buffer with the IV. The contents of the
+     * buffer are copied to protect against subsequent modification.
+     * @return the bytes of AES encryption
+     */
+    fun encryptAES(
+        data: ByteArray?,
+        key: ByteArray?,
+        transformation: String?,
+        iv: ByteArray?
+    ): ByteArray? {
+        return symmetricTemplate(data, key, "AES", transformation!!, iv, true)
+    }
+
+
+    /**
+     * Return the bytes of AES decryption for Base64-encode bytes.
+     *
+     * @param data           The data.
+     * @param key            The key.
+     * @param transformation The name of the transformation, e.g., *DES/CBC/PKCS5Padding*.
+     * @param iv             The buffer with the IV. The contents of the
+     * buffer are copied to protect against subsequent modification.
+     * @return the bytes of AES decryption for Base64-encode bytes
+     */
+    fun decryptBase64AES(
+        data: ByteArray?,
+        key: ByteArray?,
+        transformation: String?,
+        iv: ByteArray?
+    ): ByteArray? {
+        return decryptAES(Base64.decode(data, Base64.NO_WRAP), key, transformation, iv)
+    }
+
+    /**
+     * Return the bytes of AES decryption.
+     *
+     * @param data           The data.
+     * @param key            The key.
+     * @param transformation The name of the transformation, e.g., *DES/CBC/PKCS5Padding*.
+     * @param iv             The buffer with the IV. The contents of the
+     * buffer are copied to protect against subsequent modification.
+     * @return the bytes of AES decryption
+     */
+    fun decryptAES(
+        data: ByteArray?,
+        key: ByteArray?,
+        transformation: String?,
+        iv: ByteArray?
+    ): ByteArray? {
+        return symmetricTemplate(data, key, "AES", transformation!!, iv, false)
+    }
+
+
+    /**
+     * Return the bytes of symmetric encryption or decryption.
+     *
+     * @param data           The data.
+     * @param key            The key.
+     * @param algorithm      The name of algorithm.
+     * @param transformation The name of the transformation, e.g., <i>DES/CBC/PKCS5Padding</i>.
+     * @param isEncrypt      True to encrypt, false otherwise.
+     * @return the bytes of symmetric encryption or decryption
+     */
+
+    private fun symmetricTemplate(
+        data: ByteArray?,
+        key: ByteArray?,
+        algorithm: String,
+        transformation: String,
+        iv: ByteArray?,
+        isEncrypt: Boolean
+    ): ByteArray? {
+        return if (data == null || data.isEmpty() || key == null || key.isEmpty()) null else try {
+            val keySpec = SecretKeySpec(key, algorithm)
+            val cipher = Cipher.getInstance(transformation)
+            if (iv == null || iv.isEmpty()) {
+                cipher.init(if (isEncrypt) Cipher.ENCRYPT_MODE else Cipher.DECRYPT_MODE, keySpec)
+            } else {
+                val params: AlgorithmParameterSpec = IvParameterSpec(iv)
+                cipher.init(
+                    if (isEncrypt) Cipher.ENCRYPT_MODE else Cipher.DECRYPT_MODE,
+                    keySpec,
+                    params
+                )
+            }
+            cipher.doFinal(data)
+        } catch (e: Throwable) {
+            e.printStackTrace()
+            null
+        }
+    }
+
+
 }
\ No newline at end of file
diff --git a/epublib/src/main/java/me/ag2s/epublib/util/ResourceUtil.java b/epublib/src/main/java/me/ag2s/epublib/util/ResourceUtil.java
index d03018e26..faf42755f 100644
--- a/epublib/src/main/java/me/ag2s/epublib/util/ResourceUtil.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/ResourceUtil.java
@@ -67,9 +67,7 @@ public class ResourceUtil {
             if (s.length() != 0) {
                 if (s.contains("<img")) {
                     //加上div的话多看能点看大图，但掌阅的图会因为排版变得非常小。
-                    //body.append("<div class=\"duokan-image-single img-note\">")
-                    body.append(s);
-                    //.append("</div>");
+                    body.append("<div class=\"duokan-image-single img-note\">").append(s).append("</div>");
                 } else {
                     body.append("<p>").append(s).append("</p>");
                 }
diff --git a/epublib/src/main/java/me/ag2s/epublib/util/StringUtil.java b/epublib/src/main/java/me/ag2s/epublib/util/StringUtil.java
index b24a283dd..acb3093e9 100644
--- a/epublib/src/main/java/me/ag2s/epublib/util/StringUtil.java
+++ b/epublib/src/main/java/me/ag2s/epublib/util/StringUtil.java
@@ -275,13 +275,16 @@ public class StringUtil {
     }
     public static String FixTrim(String s) {
         if (s==null){
-            return "null";
+            return "";
         }
         Pattern r = Pattern.compile("^[\\s]{1,9}(.*?)[\\s]{1,9}$");
         Matcher m = r.matcher(s);
         if (m.find()) {
             s= m.group(1);
         }
+        if(s==null){
+            return "";
+        }
         //移除GBK中文全角空格
         s = s.replace("　", "");
         return s;