diff --git a/doc/api/auth/pubkey.example.json b/doc/api/auth/pubkey.example.json
new file mode 100644
index 0000000..8e48364
--- /dev/null
+++ b/doc/api/auth/pubkey.example.json
@@ -0,0 +1,9 @@
+{
+    "$schema": "pubkey.zh_CN.json",
+    "ok": true,
+    "code": 0,
+    "result": {
+        "key": "-----BEGIN PUBLIC KEY-----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\nTq8VH9KvovUBz2S9cxFz0ZUCAwEAAQ==\n-----END PUBLIC KEY-----\n",
+        "generated_time": 1663650244
+    }
+}
diff --git a/doc/api/auth/pubkey.zh_CN.json b/doc/api/auth/pubkey.zh_CN.json
new file mode 100644
index 0000000..0487f3b
--- /dev/null
+++ b/doc/api/auth/pubkey.zh_CN.json
@@ -0,0 +1,39 @@
+{
+    "$schema": "http://json-schema.org/draft-07/schema",
+    "$id": "https://github.com/lifegpc/pixiv_downloader/raw/master/doc/api/auth/pubkey.zh_CN.json",
+    "title": "返回结果",
+    "type": "object",
+    "properties": {
+        "ok": {
+            "description": "请求是否成功",
+            "type": "boolean"
+        },
+        "code": {
+            "description": "错误代码，如请求成功则为0",
+            "type": "integer"
+        },
+        "msg": {
+            "description": "错误信息",
+            "type": "string"
+        },
+        "debug_msg": {
+            "description": "调试用的错误信息"
+        },
+        "result": {
+            "description": "请求结果",
+            "type": "object",
+            "properties": {
+                "key": {
+                    "description": "RSA公钥",
+                    "type": "string"
+                },
+                "generated_time": {
+                    "description": "公钥生成时间",
+                    "type": "integer"
+                }
+            },
+            "required": ["key", "generated_time"]
+        }
+    },
+    "required": ["ok", "code"]
+}
diff --git a/src/server/auth/pubkey.rs b/src/server/auth/pubkey.rs
index 953a6f6..a134f76 100644
--- a/src/server/auth/pubkey.rs
+++ b/src/server/auth/pubkey.rs
@@ -1,8 +1,12 @@
 use super::super::preclude::*;
 use crate::ext::{json::ToJson2, try_err::TryErr};
 use crate::gettext;
+use bytes::BytesMut;
 use chrono::{DateTime, Utc};
-use openssl::{pkey::Private, rsa::Rsa};
+use openssl::{
+    pkey::Private,
+    rsa::{Padding, Rsa},
+};
 
 pub struct RSAKey {
     pub key: Rsa<Private>,
@@ -17,6 +21,23 @@ impl RSAKey {
         })
     }
 
+    pub fn decrypt(&self, data: &[u8]) -> Result<BytesMut, openssl::error::ErrorStack> {
+        let tosize = data.len();
+        let mut buf = BytesMut::with_capacity(tosize);
+        buf.resize(tosize, 0);
+        let mut i = 0;
+        let mut real = 0;
+        while i < tosize {
+            let i2 = i + self.key.size() as usize;
+            real += self
+                .key
+                .private_decrypt(&data[i..i2], &mut buf[i..i2], Padding::PKCS1)?;
+            i = i2;
+        }
+        buf.truncate(real);
+        Ok(buf)
+    }
+
     pub fn is_too_old(&self) -> bool {
         self.generated_time < Utc::now() - chrono::Duration::hours(1)
     }