Troubleshooting PIsP (formerly PuTTYGen): Common Errors and Fixes
1. “Couldn’t load private key (unsupported cipher)”
- Cause: OpenSSH private key uses a newer/encrypted format PuTTY/PIsP doesn’t accept.
- Fix:
- Re-encrypt key with a supported cipher (3DES) on a system with OpenSSL:
Code
openssl rsa -in ~/.ssh/id_rsa -des3 -out ~/.ssh/id_rsa.3des - Transfer the re-encrypted file and use PIsP → Conversions → Import key, then Save private key (.ppk).
- Re-encrypt key with a supported cipher (3DES) on a system with OpenSSL:
2. “Unrecognized key file” or “invalid key”
- Cause: Key is in OpenSSH format (or another format) while the client expects PPK, or the key file is corrupted.
- Fix:
- Open the key in PIsP and export to the needed format: Conversions → Export OpenSSH key (or Save private key as .ppk).
- If corrupted, regenerate the key pair and re-deploy the public key to servers.
3. Passphrase issues (wrong or repeatedly requested)
- Cause: Entering wrong passphrase or using a key with a different passphrase than expected.
- Fix:
- Verify the passphrase by loading the private key in PIsP. If forgotten, you must generate a new key pair and update authorized_keys on targets.
- To remove/change passphrase: load key → enter passphrase → Save private key and supply no passphrase (or new one).
4. Public key not accepted by server (Auth fail)
- Cause: Wrong public key format, extra whitespace/newlines, incorrect placement, or wrong permissions.
- Fix:
- Ensure you upload the contents of the .pub file (OpenSSH-format) to ~/.ssh/authorizedkeys on the server as a single line.
- Set correct permissions on server:
Code
chmod 700 ~/.ssh chmod 600 ~/.ssh/authorized_keys - If server expects OpenSSH format, convert .ppk → OpenSSH: load .ppk in PIsP → Conversions → Export OpenSSH key, then use that public key.
5. Conversion errors between PPK and OpenSSH
- Cause: Version/format mismatch (new OpenSSH key formats or unsupported algorithms).
- Fix:
- Update PIsP to the latest release.
- If conversion still fails, regenerate keys with a supported algorithm (rsa 4096 or ed25519) using ssh-keygen or PIsP, then distribute the public key.
6. GUI/app crashes or missing “Conversions” menu
- Cause: Broken install, old version, or using a trimmed package.
- Fix:
- Install latest official PIsP/PuTTY release from the vendor site.
- Use the standalone puttygen executable matching your OS (⁄64-bit).
- Run as administrator if access/permissions block loading.
7. Line-ending or file extension problems when saving public key (.pub)
- Cause: Editor adds wrong extension or converts line endings.
- Fix:
- Save the public key as plain text with a .pub extension and LF line endings. On Windows, explicitly name file like keyname.pub (include extension) in Save dialog.
Quick checklist to resolve most issues
- Update PIsP to latest version.
- Confirm key format matches the target (PPK vs OpenSSH).
- Use Conversions menu for import/export.
- Check passphrase correctness or regenerate keys if lost.
- Verify server-side authorized_keys content and permissions.
If you want, I can produce exact command examples for your OS (Windows, macOS, or Linux) and a short step-by-step conversion or regeneration procedure.
Leave a Reply