diff --git a/app/src/main/assets/help/jsHelp.md b/app/src/main/assets/help/jsHelp.md
index d7b312197..1f91ed457 100644
--- a/app/src/main/assets/help/jsHelp.md
+++ b/app/src/main/assets/help/jsHelp.md
@@ -132,7 +132,8 @@ deleteFile(path: String)
 ```
 ****
 > [常见加密解密算法介绍](https://www.yijiyong.com/algorithm/encryption/01-intro.html)
-> [相关概念](https://blog.csdn.net/OrangeJack/article/details/82913804)  
+> [相关概念](https://blog.csdn.net/OrangeJack/article/details/82913804)
+> [Android支持的transformation](https://developer.android.google.cn/reference/kotlin/javax/crypto/Cipher?hl=en)
 * AES
 > transformation默认实现AES/ECB/PKCS5Padding
 ```
@@ -163,14 +164,14 @@ java.tripleDESEncodeBase64Str(data: String,key: String,mode: String,padding: Str
 java.tripleDESDecodeStr(data: String,key: String,mode: String,padding: String,iv: String): String?
 ```
 * 摘要
-> algorithm支持MD2 MD5 SHA-1 SHA-256 SHA-384 SHA-512
+> algorithm支持MD5 SHA-1 SHA-224 SHA-256 SHA-384 SHA-512
 ```
 java.digestHex(data: String, algorithm: String,): String?
 
 java.digestBase64Str(data: String, algorithm: String,): String?
 ```
 * HMac(散列消息鉴别码)
-> algorithm支持HmacMD5 HmacSHA1 HmacSHA224 HmacSHA256 HmacSHA384 HmacSHA512
+> algorithm支持DESMAC DESMAC/CFB8 DESedeMAC DESedeMAC/CFB8 DESedeMAC64 DESwithISO9797 HmacMD5 HmacSHA* ISO9797ALG3MAC PBEwithSHA*
 ```
 java.HMacHex(data: String, algorithm: String, key: String): String
 
diff --git a/app/src/main/java/io/legado/app/utils/DigestUtils.kt b/app/src/main/java/io/legado/app/utils/DigestUtils.kt
index 43597c9c9..f179d3a86 100644
--- a/app/src/main/java/io/legado/app/utils/DigestUtils.kt
+++ b/app/src/main/java/io/legado/app/utils/DigestUtils.kt
@@ -9,7 +9,8 @@ object DigestUtils {
 
     /**
      * 消息摘要
-     * MD2 MD5 SHA-1 SHA-256 SHA-384 SHA-512
+     * 支持MD5 SHA-1 SHA-224 SHA-256 SHA-384 SHA-512
+     * https://developer.android.google.cn/reference/java/security/MessageDigest?hl=en
      */
     fun getDigest(
         algorithm: String,
@@ -36,7 +37,8 @@ object DigestUtils {
 
     /**
      * 散列消息鉴别码
-     * HmacMD5 HmacSHA1 HmacSHA224 HmacSHA256 HmacSHA384 HmacSHA512
+     * 支持DESMAC DESMAC/CFB8 DESedeMAC DESedeMAC/CFB8 DESedeMAC64 DESwithISO9797 HmacMD5 HmacSHA* ISO9797ALG3MAC PBEwithSHA*
+     * https://developer.android.google.cn/reference/kotlin/javax/crypto/Mac?hl=en
      */
     fun getHMac(
         algorithm: String,
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 50d67e521..f410075ec 100644
--- a/app/src/main/java/io/legado/app/utils/EncoderUtils.kt
+++ b/app/src/main/java/io/legado/app/utils/EncoderUtils.kt
@@ -6,6 +6,9 @@ import javax.crypto.Cipher
 import javax.crypto.spec.IvParameterSpec
 import javax.crypto.spec.SecretKeySpec
 
+/**
+ * transformations https://developer.android.google.cn/reference/kotlin/javax/crypto/Cipher?hl=en
+ */
 @Suppress("unused")
 object EncoderUtils {