A PPK file is a file that stores a private key and its corresponding public key. Here's a more detailed breakdown:
Key Components of a PPK File
- Private Key: This is the secret key used for encrypting data or authenticating your identity. It's crucial to keep this key safe and never share it.
- Public Key: This key is used to decrypt data that has been encrypted with the corresponding private key. You can share this key freely.
- Storage: Both the private and public keys are contained within the same PPK file.
Encryption of the Private Key
The private key inside a PPK file can be stored in two ways:
- Unencrypted: The private key is stored in clear text.
- Encrypted: The private key is encrypted for added security. However, the public key is always stored in clear text in both scenarios.
How PPK Files Are Used
PPK files are primarily used for secure connections, typically with applications like PuTTY, a popular SSH client for Windows. They provide a convenient way to manage SSH keys for secure authentication:
- Secure Authentication: PPK files are frequently used for SSH key-based authentication, which is more secure than traditional password-based login. Instead of entering a password every time, you can use the PPK file to authenticate your connection.
- Key Management: You can store a private key in a PPK file, which helps with managing different keys across multiple servers.
Example Use Case
Suppose you want to connect to a remote Linux server. Instead of entering your username and password each time, you can:
- Generate a public/private key pair using PuTTYgen (a key generator provided by PuTTY).
- Save the private key as a PPK file (e.g., my_private_key.ppk).
- Copy the public key content and add it to the authorized_keys file on the server.
- When connecting with PuTTY, use the saved my_private_key.ppk file for authentication.
Summary Table
| Feature | Description |
|---|---|
| Purpose | Stores a private key and its corresponding public key |
| Key Storage | Both keys are contained in the same file |
| Private Key | Can be stored unencrypted or encrypted; for secure authentication, keep this key secret |
| Public Key | Always stored in cleartext; can be freely distributed |
| Use Case | Secure SSH connections, primarily with applications like PuTTY |
