How to secure SSH Private key on Windows 10

I'm using the new ssh client for windows 10 and when trying to connect with a private key I'm getting this error:

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@         WARNING: UNPROTECTED PRIVATE KEY FILE!          @
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Permissions for 'MyPair.pem' are too open. It is required that your
private key files are NOT accessible by others. This private key will
be ignored. Load key "MyPair.pem": bad permissions [email protected]:
Permission denied (publickey).

I know that if I was on Linux I would need to run chmod 600 to set the file permissions, but what do you use on Windows 10?

Solution 1:

Keys must only be accessible to the user they're intended for and no other account, service, or group.

• GUI:
  [File] Properties → Security → Advanced
  1. Owner: The key's user
  2. Permission Entries: Remove all except for the key's user
  3. Set key's user to Full Control
     
     
• Cmd:

  ::# Set Key File Variable:
      Set Key="%UserProfile%\.ssh\id_rsa"
  
  ::# Remove Inheritance:
      Icacls %Key% /c /t /Inheritance:d
  
  ::# Set Ownership to Owner:
      Icacls %Key% /c /t /Grant %UserName%:F
  
  ::# Remove All Users, except for Owner:
      Icacls %Key%  /c /t /Remove Administrator BUILTIN\Administrators BUILTIN Everyone System Users
  
  ::# Verify:
      Icacls %Key%
  
  ::# Remove Variable:
      set "Key="
  
  

  
  
• PowerShell:

  # Set Key File Variable:
    New-Variable -Name Key -Value "$env:UserProfile\.ssh\id_rsa"
  
  # Remove Inheritance:
    Icacls $Key /c /t /Inheritance:d
  
  # Set Ownership to Owner:
    Icacls $Key /c /t /Grant $env:UserName:F
  
  # Remove All Users, except for Owner:
    Icacls $Key  /c /t /Remove Administrator BUILTIN\Administrators BUILTIN Everyone System Users
  
  # Verify:
    Icacls $Key
  
  # Remove Variable:
    Remove-Variable -Name Key
  
  

  
  
• WSL/Cygwin:

  # Set Variables:
    # Key File:
      key="/path/to/key"
  
    # User:
      user="$(echo $USER)"
  
  # Set Ownership to Owner: (assumes user's name is also user's group name)
    chown $user:$user $key
  
  # Set Access Rights
    chmod 0600 $key
  
  # Verify
    ls -l $key