PEM to PPK Converter

PPK stands for PuTTY Private Key. It's the file format created by Simon Tatham for the PuTTY SSH client on Windows. PPK files (both version 2 and version 3) store the private key, the corresponding public key, and metadata like the key type and encryption method in a single structured text file. PPK version 3 (introduced in PuTTY 0.75) uses stronger key derivation (Argon2) compared to version 2's SHA-1-based approach.

PEM (Privacy-Enhanced Mail) is a base64-encoded format with distinctive '-----BEGIN/END-----' markers, used by OpenSSH and OpenSSL on Linux, macOS, and most cloud platforms. PPK (PuTTY Private Key) is a proprietary format used by PuTTY and Windows-based SSH tools (WinSCP, FileZilla). PEM stores the key in a single encoded block, while PPK stores public and private components separately in a structured text file with additional metadata. The cryptographic key data is the same — only the container format differs.

No, PuTTY cannot read PEM files directly — it only accepts its own PPK format. When you try to load a PEM file in PuTTY, you'll get an error. However, some newer PuTTY-based tools (like the latest WinSCP) can auto-convert PEM files when you load them. For PuTTY itself, you must convert with PuTTYgen first: open PuTTYgen, go to Conversions > Import key, select your PEM file, then Save private key.

Install PuTTY tools via Homebrew: 'brew install putty'. Then convert with: 'puttygen key.pem -o key.ppk'. If you need the PPK for a Windows machine, transfer the resulting .ppk file. Note that on macOS, you typically don't need PPK at all — the built-in ssh command uses PEM/OpenSSH format natively. PPK is only needed if you specifically use PuTTY on Windows.

PuTTYgen (the command-line version 'puttygen') is the only reliable tool for creating PPK files, as PPK is PuTTY's proprietary format. On macOS, install it with 'brew install putty', then run 'puttygen key.pem -o key.ppk'. On Linux, install with 'apt install putty-tools' or 'yum install putty'. There is no built-in OpenSSH command to create PPK files — you need the puttygen tool.