diff --git a/conf-sshd.sh b/conf-sshd.sh
index 9935835..de97ccf 100755
--- a/conf-sshd.sh
+++ b/conf-sshd.sh
@@ -1,4 +1,6 @@
 #!/bin/bash
+set -e
+set -o pipefail
 
 ########## 一些配置 ##########
 
@@ -11,10 +13,10 @@ script_url="{{ SCRIPT_URL }}"
 
 ############ 脚本区 ##########
 
-script_params=$*
+script_params=("$@")
 has_param() {
-    for param in $script_params; do
-        for tParam in $@; do
+    for param in "${script_params[@]}"; do
+        for tParam in "$@"; do
             if [ "$tParam" == "$param" ]; then
                 echo "true"
                 return
@@ -26,15 +28,16 @@ has_param() {
 
 get_param_value() {
     local find=false
-    for param in $script_params; do
+    for param in "${script_params[@]}"; do
         if [ "$find" == "true" ]; then
             if [[ $param == -* ]]; then
                 return
             fi
-            echo $param
+
+            echo "$param" 
             return
         fi
-        for tParam in $@; do
+        for tParam in "$@"; do
             if [ "$tParam" == "$param" ]; then
                 find=true
                 break
@@ -44,67 +47,161 @@ get_param_value() {
 }
 
 # 帮助信息.
-if [ $(has_param "-h" "--help") == "true" ]; then
+if [ "$(has_param "-h" "--help")" == "true" ]; then
     echo "Usage: $0 [options]"
     echo "Options:"
-    echo "  -h, --help                              Print this help message."
+    echo "  -h, --help                          Print this help message."
     echo ""
     echo "Available to any user: "
-    echo "  -c, --cron [cron | false]               Configure Crontab to automatically update ssh keys,"
-    echo "                                          Cron expression can be specified, If false is specified, "
-    echo "                                          Crontab settings will be deleted automatically."
+    echo "  -c, --cron \"<cron> | false\"       Configure Crontab to automatically update ssh keys."
+    echo "                                      Cron expression MUST be quoted (e.g., \"* 0 * * *\")."
+    echo "                                      If 'false' is specified, Crontab settings will be deleted."
     echo ""
-    echo "  -o, --only-update-keys                  Only update SSH keys, do not configure ssh server."
-    echo "  -u, --update-self                       Update this script to the latest version."
+    echo "  -o, --only-update-keys            Only update SSH keys, do not configure ssh server."
+    echo "  -u, --update-self                 Update this script to the latest version."
+    echo "  --uninstall                       Uninstall this script (remove cron and local files)."
     echo ""
     echo "only available when the script is executed as root:"
-    echo "  -n, --no-install-sshd                   Do not install SSH Server."
-    echo "  -p, --allow-root-passwd <yes | no>      Allow Root to log in with a password."
+    echo "  -n, --no-install-sshd             Do not install SSH Server."
+    echo "  -p, --allow-root-passwd <yes | no>  Allow Root to log in with a password."
     echo ""
     exit 0
 fi
 
 update_sshkeys() {
-    if [ "$sshkey_url" == "" ]; then
-        echo "Please specify the URL of the SSH public key."
+    if [ "$sshkey_url" == "" ] || [[ "$sshkey_url" == "{{"* ]]; then
+        echo "ERROR: sshkey_url is not configured."
         exit 1
     fi
+
     echo "Downloading SSH public key from '$sshkey_url'"
     mkdir -p ~/.ssh
-    local ssh_keys=$(curl -s $sshkey_url)
-    if [ $? -ne 0 ] || [ "$ssh_keys" == "" ]; then
-        echo "Failed to download SSH public key at $(date '+%Y-%m-%d %H:%M:%S')"
+    chmod 700 ~/.ssh
+
+    local dl_tmp_file=~/.ssh/authorized_keys.dl.tmp
+    if ! curl -sL "$sshkey_url" -o "$dl_tmp_file"; then 
+        echo "Failed to download SSH public key at $(date '+%Y-m-d %H:%M:%S')"
+        rm -f "$dl_tmp_file"
         exit 1
     fi
+
+    if [ ! -s "$dl_tmp_file" ] || ! grep -qE "(ssh-rsa|ssh-ed25519|ecdsa-sha2-nistp)" "$dl_tmp_file"; then
+        echo "Downloaded file is empty or does not contain valid SSH key types at $(date '+%Y-m-d %H:%M:%S')"
+        echo "Aborting update to prevent lockout."
+        rm -f "$dl_tmp_file"
+        exit 1
+    fi
+    
     echo "-------------------- SSH Keys --------------------"
-    echo "$ssh_keys"
+    cat "$dl_tmp_file"
     echo "--------------------------------------------------"
-    echo "$ssh_keys" > ~/.ssh/authorized_keys
-    chmod 600 ~/.ssh/authorized_keys
-    # 输出更新成功，需要附带时间日期
-    echo "SSH public key updated successfully at $(date '+%Y-%m-%d %H:%M:%S')"
+    
+    local auth_file=~/.ssh/authorized_keys
+    local new_auth_file=~/.ssh/authorized_keys.new.tmp
+    
+    # 受管理文本块标记
+    local begin_marker="# --- BEGIN MANAGED BY CONF-SSHD SCRIPT ---"
+    local end_marker="# --- END MANAGED BY CONF-SSHD SCRIPT ---"
+
+    local managed_block_found=false
+    local inside_managed_block=false
+
+    touch "$auth_file"
+    true > "$new_auth_file"
+
+    # 逐行读取文件
+    while IFS= read -r line; do
+        if [ "$line" == "$begin_marker" ]; then
+            managed_block_found=true
+            inside_managed_block=true
+            
+            {
+                echo "" # 确保和前面的内容有空行
+                echo "$begin_marker"
+                cat "$dl_tmp_file"
+                echo "$end_marker"
+            } >> "$new_auth_file"
+            
+        elif [ "$line" == "$end_marker" ]; then
+            inside_managed_block=false
+        elif [ "$inside_managed_block" == "false" ]; then
+            echo "$line" >> "$new_auth_file"
+        fi
+    done < "$auth_file"
+
+    if [ "$managed_block_found" == "false" ]; then
+        {
+            echo "" # 确保和前面的内容有空行
+            echo "$begin_marker"
+            cat "$dl_tmp_file"
+            echo "$end_marker"
+        } >> "$new_auth_file"
+    fi
+
+    mv "$new_auth_file" "$auth_file"
+    rm -f "$dl_tmp_file"
+
+    chmod 600 "$auth_file"
+    echo "SSH public key updated successfully (managed block only) at $(date '+%Y-m-d %H:%M:%S')"
 }
 
+# 检查是否指定了 --uninstall
+if [ "$(has_param "--uninstall")" == "true" ]; then
+    echo "Uninstalling conf-sshd (disabling auto-updates)..."
+    
+    if [ "$(command -v crontab)" != "" ]; then
+        echo "Removing Crontab entry..."
+        (crontab -l 2>/dev/null || true | grep -v "conf-sshd.sh") | crontab -
+    else
+        echo "Crontab utility not found, skipping Crontab removal."
+    fi
+
+    script_dir="$HOME/.conf-sshd"
+    if [ -d "$script_dir" ]; then
+        echo "Removing script files from $script_dir..."
+        rm -rf "$script_dir"
+    else
+        echo "Script directory $script_dir not found, skipping removal."
+    fi
+
+    echo "Uninstall complete."
+    echo "Note: authorized_keys managed block and sshd_config were NOT affected."
+    exit 0
+fi
+
 # 检查是否只更新密钥.
-if [ $(has_param "-o" "--only-update-keys") == "true" ]; then
+if [ "$(has_param "-o" "--only-update-keys")" == "true" ]; then
     update_sshkeys
     exit 0
 fi
 
 # 检查是否指定了 --update-self
-if [ $(has_param "-u" "--update-self") == "true" ]; then
+if [ "$(has_param "-u" "--update-self")" == "true" ]; then
     echo "Updating conf-sshd script..."
-    cp $0 ~/.conf-sshd/conf-sshd.sh.bak
-    curl -s $script_url > $0 || cp ~/.conf-sshd/conf-sshd.sh.bak $0 && echo "Script update failed at $(date '+%Y-%m-%d %H:%M:%S')" && exit 1
-    chmod +x ~/.conf-sshd/conf-sshd.sh
+    mkdir -p ~/.conf-sshd # 确保目录存在
+    target_script=~/.conf-sshd/conf-sshd.sh
+
+    if [ -f "$target_script" ]; then
+        cp "$target_script" "$target_script.bak"
+    fi
+
+    # 下载到临时文件
+    if ! curl -sL "$script_url" -o "$target_script.tmp"; then
+         echo "Script download failed at $(date '+%Y-%m-%d %H:%M:%S')"
+         rm -f "$target_script.tmp"
+         exit 1
+    fi
+
+    mv "$target_script.tmp" "$target_script"
+
+    chmod +x "$target_script"
     echo "Script updated successfully at $(date '+%Y-%m-%d %H:%M:%S')"
     exit 0
 fi
 
-# 检查 /usr/sbin/sshd 是否存在，且 /usr/sbin/sshd 执行后退出代码为 0
-/usr/sbin/sshd -T > /dev/null
-if [ $? -ne 0 ] && [ $(has_param "-n" "--no-install-sshd") == "false" ]; then
-    if [ $(id -u) -eq 0 ]; then
+# 检查 SSHD 是否安装.
+if ! /usr/sbin/sshd -T > /dev/null 2>&1 && [ "$(has_param "-n" "--no-install-sshd")" == "false" ]; then
+    if [ "$(id -u)" -eq 0 ]; then
         echo "The ssh server is not installed, and the script is executed as root, so it will be installed."
         if [ -f /etc/redhat-release ]; then
             yum install -y openssh-server
@@ -122,23 +219,32 @@ else
 fi
 
 # 检查是否指定了 --allow-root-passwd
-if [ $(has_param "-p" "--allow-root-passwd") == "true" ]; then
+if [ "$(has_param "-p" "--allow-root-passwd")" == "true" ]; then
     # 检查当前用户是否为 root
-    if [ $(id -u) -eq 0 ]; then
-        # 获取参数值
+    if [ "$(id -u)" -eq 0 ]; then
         allow_root_passwd=$(get_param_value "-p" "--allow-root-passwd" | tr '[:upper:]' '[:lower:]')
+        
+        sshd_config_file="/etc/ssh/sshd_config"
+        new_sshd_permit_root_login_setting=""
+
         if [ "$allow_root_passwd" == "yes" ]; then
-            # 设置允许 root 使用密码登录
-            sed -i 's/^#?PermitRootLogin.*/PermitRootLogin yes/g' /etc/ssh/sshd_config
-            echo "Root user is allowed to log in with password."
+            new_sshd_permit_root_login_setting="PermitRootLogin yes"
+            echo "Setting: Root user is allowed to log in with password."
         elif [ "$allow_root_passwd" == "no" ]; then
-            # 设置禁止 root 使用密码登录
-            sed -i 's/^#?PermitRootLogin.*/PermitRootLogin prohibit-password/g' /etc/ssh/sshd_config
-            echo "Root user is prohibited from logging in with password."
+            new_sshd_permit_root_login_setting="PermitRootLogin prohibit-password"
+            echo "Setting: Root user is prohibited from logging in with password."
         else
-            echo "Please specify whether to allow root to log in with a password."
+            echo "Please specify 'yes' or 'no' for --allow-root-passwd."
             exit 1
         fi
+
+        if grep -qE '^#?PermitRootLogin' "$sshd_config_file"; then
+            sed -i "s@^#?PermitRootLogin.*@$new_sshd_permit_root_login_setting@g" "$sshd_config_file"
+        else
+            echo "$new_sshd_permit_root_login_setting" >> "$sshd_config_file"
+        fi
+        echo "SSHD config updated. Please restart sshd service to apply changes."
+
     else
         echo "The script is executed as a non-root user and cannot set whether to allow root to log in with a password."
         exit 1
@@ -149,10 +255,10 @@ fi
 update_sshkeys
 
 # 检查是否指定了 --cron
-if [ $(has_param "-c" "--cron") == "true" ]; then
+if [ "$(has_param "-c" "--cron")" == "true" ]; then
     # 检查 Crontab 是否已安装
     if [ "$(command -v crontab)" == "" ]; then
-        if [ $(id -u) -eq 0 ]; then
+        if [ "$(id -u)" -eq 0 ]; then
             echo "The crontab is not installed, and the script is executed as a root user, so it will be installed."
             if [ -f /etc/redhat-release ]; then
                 yum install -y crontabs
@@ -171,11 +277,11 @@ if [ $(has_param "-c" "--cron") == "true" ]; then
     cron=$(get_param_value "-c" "--cron" | tr '[:upper:]' '[:lower:]')
     if [ "$cron" == "false" ]; then
         # 检查 Crontab 是否已经设置
-        if [ "$(crontab -l | grep "conf-sshd.sh")" == "" ]; then
-            echo "Crontab will not be configured."
+        if [ "$( (crontab -l 2>/dev/null || true) | grep -c "conf-sshd.sh" )" -eq 0 ]; then
+            echo "Crontab already clean. Will not be configured."
             exit 0
         else
-            crontab -l | grep -v "conf-sshd.sh" | crontab -
+            (crontab -l 2>/dev/null || true) | grep -v "conf-sshd.sh" | crontab -
             echo "Crontab has been removed."
             exit 0
         fi
@@ -186,20 +292,22 @@ if [ $(has_param "-c" "--cron") == "true" ]; then
         # 将当前脚本移动到 ~/.conf-sshd/conf-sshd.sh 中.
         mkdir -p ~/.conf-sshd
         # 检查当前脚本是否为文件
-        if [ ! -f $0 ]; then
+        if [ ! -f "$0" ]; then
             echo "Downloading conf-sshd script..."
-            curl -o ~/.conf-sshd/conf-sshd.sh $script_url
+            curl -oL ~/.conf-sshd/conf-sshd.sh "$script_url"
         else 
             echo "Copying conf-sshd script..."
-            cp $0 ~/.conf-sshd/conf-sshd.sh
+            cp "$0" ~/.conf-sshd/conf-sshd.sh
         fi
         chmod +x ~/.conf-sshd/conf-sshd.sh
         echo "Install conf-sshd script successfully."
         # 将当前脚本追加到当前用户的 Crontab 中
-        crontab -l > ~/.conf-sshd/crontab.old
-        echo "$cron \"/bin/bash ~/.conf-sshd/conf-sshd.sh -o\" >> ~/.conf-sshd/run.log" >> ~/.conf-sshd/crontab.old
-        crontab ~/.conf-sshd/crontab.old
-        rm ~/.conf-sshd/crontab.old
+        echo "Configuring Crontab..."
+        cron_command="\"/bin/bash ~/.conf-sshd/conf-sshd.sh -o\" >> ~/.conf-sshd/run.log 2>&1"
+        cron_job="$cron $cron_command"
+
+        (crontab -l 2>/dev/null || true | grep -v "conf-sshd.sh") | { cat; echo "$cron_job"; } | crontab -
+
         echo "Crontab has been configured.(Cron: '$cron')"
     fi
 fi