(PowerShell) Convert PuTTY Private Key (ppk) to OpenSSH (pem)

Convert a PuTTY format private key file (.ppk) to OpenSSH (.pem).

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

$key = New-Object Chilkat.SshKey

# Load an unencrypted or encrypted PuTTY private key.

# If  your PuTTY private key is encrypted, set the Password
# property before calling FromPuttyPrivateKey.
# If your PuTTY private key is not encrypted, it makes no diffference
# if Password is set or not set.
$key.Password = "secret"

# First load the .ppk file into a string:

$keyStr = $key.LoadText("putty_private_key.ppk")

# Import into the SSH key object:
$success = $key.FromPuttyPrivateKey($keyStr)
if ($success -ne $true) {
    $($key.LastErrorText)
    exit
}

# Convert to an encrypted or unencrypted OpenSSH key.

# First demonstrate converting to an unencrypted OpenSSH key

$bEncrypt = $false
$unencryptedKeyStr = $key.ToOpenSshPrivateKey($bEncrypt)
$success = $key.SaveText($unencryptedKeyStr,"unencrypted_openssh.pem")
if ($success -ne $true) {
    $($key.LastErrorText)
    exit
}

# Save to an encrypted OpenSSH PEM file:

$bEncrypt = $true
$key.Password = "myPassword"
$encryptedKeyStr = $key.ToOpenSshPrivateKey($bEncrypt)
$success = $key.SaveText($encryptedKeyStr,"encrypted_openssh.pem")
if ($success -ne $true) {
    $($key.LastErrorText)
    exit
}

$("Done!")