diff --git a/README.md b/README.md
index fa3770c..7365cdb 100644
--- a/README.md
+++ b/README.md
@@ -70,19 +70,19 @@ curl -fsSL "https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-pi.s
 **tmux:**
 
 ```powershell
-powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-tmux.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-tmux.ps1' -OutFile $t; & $t"
+powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-tmux.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-tmux.ps1' -OutFile $t; & $t"
 ```
 
 **bottom:**
 
 ```powershell
-powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-bottom.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-bottom.ps1' -OutFile $t; & $t"
+powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-bottom.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-bottom.ps1' -OutFile $t; & $t"
 ```
 
 **lazygit:**
 
 ```powershell
-powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-lazygit.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-lazygit.ps1' -OutFile $t; & $t"
+powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-lazygit.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-lazygit.ps1' -OutFile $t; & $t"
 ```
 
 **Docker:** [Docker Desktop for Windows](https://www.docker.com/products/docker-desktop/)를 설치하세요. 또는 WSL2에서 리눅스용 `install-docker.sh`를 실행하세요.
@@ -90,7 +90,7 @@ powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-lazygit.ps1\"; iwr
 **ctop:**
 
 ```powershell
-powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-ctop.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-ctop.ps1' -OutFile $t; & $t"
+powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-ctop.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-ctop.ps1' -OutFile $t; & $t"
 ```
 
 **uv:**
@@ -108,7 +108,7 @@ powershell -ExecutionPolicy ByPass -c "irm https://astral.sh/uv/install.ps1 | ie
 **pi (Pi Coding Agent + 추천 패키지):**
 
 ```powershell
-powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-pi.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-pi.ps1' -OutFile $t; & $t"
+powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-pi.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-pi.ps1' -OutFile $t; & $t"
 ```
 
 ## 도구별 사용법
diff --git a/install-bottom.ps1 b/install-bottom.ps1
index 84966a5..8bd81af 100644
--- a/install-bottom.ps1
+++ b/install-bottom.ps1
@@ -23,11 +23,11 @@
     .\install-bottom.ps1 -InstallDir "C:\tools\bin"
     .\install-bottom.ps1 -AddToPath $false
 
-    # One-liner install from remote (download then run; -ExecutionPolicy Bypass for current process only):
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-bottom.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-bottom.ps1' -OutFile $t; & $t"
+    # One-liner install from remote (works on Windows 10+):
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-bottom.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-bottom.ps1' -OutFile $t; & $t"
 
     # With parameters:
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-bottom.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-bottom.ps1' -OutFile $t; & $t -InstallDir 'C:\tools\bin'"
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-bottom.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-bottom.ps1' -OutFile $t; & $t -InstallDir 'C:\tools\bin'"
 
 .NOTES
     If execution policy error occurs:
diff --git a/install-ctop.ps1 b/install-ctop.ps1
index aa14633..0bed182 100644
--- a/install-ctop.ps1
+++ b/install-ctop.ps1
@@ -24,11 +24,11 @@
     .\install-ctop.ps1 -InstallDir "C:\tools\bin"
     .\install-ctop.ps1 -AddToPath $false
 
-    # One-liner install from remote (download then run; -ExecutionPolicy Bypass for current process only):
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-ctop.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-ctop.ps1' -OutFile $t; & $t"
+    # One-liner install from remote (works on Windows 10+):
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-ctop.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-ctop.ps1' -OutFile $t; & $t"
 
     # With parameters:
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-ctop.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-ctop.ps1' -OutFile $t; & $t -InstallDir 'C:\tools\bin'"
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-ctop.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-ctop.ps1' -OutFile $t; & $t -InstallDir 'C:\tools\bin'"
 
 .NOTES
     If execution policy error occurs:
diff --git a/install-lazygit.ps1 b/install-lazygit.ps1
index ec508f6..24796a7 100644
--- a/install-lazygit.ps1
+++ b/install-lazygit.ps1
@@ -23,11 +23,11 @@
     .\install-lazygit.ps1 -InstallDir "C:\tools\bin"
     .\install-lazygit.ps1 -AddToPath $false
 
-    # One-liner install from remote (download then run; -ExecutionPolicy Bypass for current process only):
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-lazygit.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-lazygit.ps1' -OutFile $t; & $t"
+    # One-liner install from remote (works on Windows 10+):
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-lazygit.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-lazygit.ps1' -OutFile $t; & $t"
 
     # With parameters:
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-lazygit.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-lazygit.ps1' -OutFile $t; & $t -InstallDir 'C:\tools\bin'"
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-lazygit.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-lazygit.ps1' -OutFile $t; & $t -InstallDir 'C:\tools\bin'"
 
 .NOTES
     If execution policy error occurs:
diff --git a/install-pi.ps1 b/install-pi.ps1
index 43e7559..fa6b31d 100644
--- a/install-pi.ps1
+++ b/install-pi.ps1
@@ -21,8 +21,8 @@
     .\install-pi.ps1
     .\install-pi.ps1 -SkipPackages
 
-    # One-liner install from remote:
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-pi.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-pi.ps1' -OutFile $t; & $t"
+    # One-liner install from remote (works on Windows 10+):
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-pi.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-pi.ps1' -OutFile $t; & $t"
 
 .NOTES
     If execution policy error occurs:
@@ -37,6 +37,9 @@ param(
 Set-StrictMode -Version Latest
 $ErrorActionPreference = 'Stop'
 
+# Force TLS 1.2+ for HTTPS downloads (required on Windows 10 / PowerShell 5.1)
+[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+
 # ────────────────────────────────────────────
 # Constants
 # ────────────────────────────────────────────
diff --git a/install-tmux.ps1 b/install-tmux.ps1
index ffc5605..23c264f 100644
--- a/install-tmux.ps1
+++ b/install-tmux.ps1
@@ -17,8 +17,8 @@
 .EXAMPLE
     .\install-tmux.ps1
 
-    # One-liner install from remote:
-    powershell -ExecutionPolicy Bypass -c "$t=\"$env:TEMP\install-tmux.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-tmux.ps1' -OutFile $t; & $t"
+    # One-liner install from remote (works on Windows 10+):
+    powershell -ExecutionPolicy Bypass -c "[Net.ServicePointManager]::SecurityProtocol=[Net.SecurityProtocolType]::Tls12; $t=\"$env:TEMP\install-tmux.ps1\"; iwr -useb 'https://gl.isitsoft.kr/publicproj/install-sh/-/raw/main/install-tmux.ps1' -OutFile $t; & $t"
 
 .NOTES
     If execution policy error occurs:
@@ -31,6 +31,9 @@ param()
 Set-StrictMode -Version Latest
 $ErrorActionPreference = 'Stop'
 
+# Force TLS 1.2+ for HTTPS downloads (required on Windows 10 / PowerShell 5.1)
+[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12
+
 # ────────────────────────────────────────────
 # Utility functions
 # ────────────────────────────────────────────