diff --git a/app/src/main/assets/help/jsHelp.md b/app/src/main/assets/help/jsHelp.md
index 2c62027ee..d26e88654 100644
--- a/app/src/main/assets/help/jsHelp.md
+++ b/app/src/main/assets/help/jsHelp.md
@@ -197,7 +197,7 @@ java.createSymmetricCrypto(transformation, key, iv)
 >解密加密参数 data支持ByteArray|Base64String|HexString|InputStream
 ```
 //解密为ByteArray String
-cipher.decrypt(data)
+cipher.decrypt(data, charset: String? = "UTF8")
 cipher.decryptStr(data)
 //加密为ByteArray Base64字符 HEX字符
 cipher.encrypt(data)
diff --git a/app/src/main/java/io/legado/app/help/crypto/AsymmetricCrypto.kt b/app/src/main/java/io/legado/app/help/crypto/AsymmetricCrypto.kt
index 844acc390..34918a6b4 100644
--- a/app/src/main/java/io/legado/app/help/crypto/AsymmetricCrypto.kt
+++ b/app/src/main/java/io/legado/app/help/crypto/AsymmetricCrypto.kt
@@ -31,37 +31,26 @@ class AsymmetricCrypto(algorithm: String) : HutoolAsymmetricCrypto(algorithm) {
         }
     }
 
-    fun decrypt(data: Any, keyType: Int): ByteArray = when {
-        data is ByteArray -> decrypt(data as ByteArray, getKeyType(keyType))
-        data is String -> decrypt(data as String, getKeyType(keyType))
-        data is InputStream -> decrypt(data as InputStream, getKeyType(keyType))
-        else -> throw IllegalArgumentException("Unexpected data input")
-    }
-    fun decryptStr(data: Any, keyType: Int): String = when {
-        data is ByteArray -> decryptStr(data as ByteArray, getKeyType(keyType))
-        data is String -> decryptStr(data as String, getKeyType(keyType))
-        data is InputStream -> decryptStr(data as InputStream, getKeyType(keyType))
-        else -> throw IllegalArgumentException("Unexpected data input")
-    }
+fun decrypt(data: ByteArray, keyType: Int): ByteArray? = decrypt(data, getKeyType(keyType))
+    fun decrypt(data: String, keyType: Int): ByteArray? = decrypt(data, getKeyType(keyType))
+    fun decrypt(data: InputStream, keyType: Int): ByteArray? = decrypt(data, getKeyType(keyType))
+
+    fun decryptStr(data: ByteArray, keyType: Int): String? = decryptStr(data, getKeyType(keyType))
+    fun decryptStr(data: String, keyType: Int): String? = decryptStr(data, getKeyType(keyType))
+    fun decryptStr(data: InputStream, keyType: Int): String? = decryptStr(data, getKeyType(keyType))
+    
+    fun encrypt(data: ByteArray, keyType: Int): ByteArray? = encrypt(data, getKeyType(keyType))
+    fun encrypt(data: String, keyType: Int): ByteArray? = encrypt(data, getKeyType(keyType))
+    fun encrypt(data: InputStream, keyType: Int): ByteArray? = encrypt(data, getKeyType(keyType))
+
+    fun encryptHex(data: ByteArray, keyType: Int): String? = encryptHex(data, getKeyType(keyType))
+    fun encryptHex(data: String, keyType: Int): String? = encryptHex(data, getKeyType(keyType))
+    fun encryptHex(data: InputStream, keyType: Int): String? = encryptHex(data, getKeyType(keyType))
+
+    fun encryptBase64(data: ByteArray, keyType: Int): String? =encryptBase64(data, getKeyType(keyType))
+    fun encryptBase64(data: String, keyType: Int): String? =encryptBase64(data, getKeyType(keyType))
+    fun encryptBase64(data: InputStream, keyType: Int): String? =encryptBase64(data, getKeyType(keyType))
 
-    fun encrypt(data: Any, keyType: Int): ByteArray = when {
-        data is ByteArray -> encrypt(data as ByteArray, getKeyType(keyType))
-        data is String -> encrypt(data as String, getKeyType(keyType))
-        data is InputStream -> encrypt(data as InputStream, getKeyType(keyType))
-        else -> throw IllegalArgumentException("Unexpected data input")
-    }
-    fun encryptHex(data: Any, keyType: Int): String = when {
-        data is ByteArray -> encryptHex(data as ByteArray, getKeyType(keyType))
-        data is String -> encryptHex(data as String, getKeyType(keyType))
-        data is InputStream -> encryptHex(data as InputStream, getKeyType(keyType))
-        else -> throw IllegalArgumentException("Unexpected data input")
-    }
-    fun encryptBase64(data: Any, keyType: Int): String = when {
-        data is ByteArray -> encryptBase64(data as ByteArray, getKeyType(keyType))
-        data is String -> encryptBase64(data as String, getKeyType(keyType))
-        data is InputStream -> encryptBase64(data as InputStream, getKeyType(keyType))
-        else -> throw IllegalArgumentException("Unexpected data input")
-    }
 
 
 }
\ No newline at end of file