This article provides information related to the error message received when trying to decrypt a file or email that has been encrypted to a private key that cannot be found on your keyring. This article pertains to PGP Desktop 8.x on Windows.
When using public key encryption, decryption can only occur if the keyring on the local machine contains the private key to which the public key portion of the key pair was encrypted to.
When this is done incorrectly, the following error message occurs: Error Message: Message/File was encrypted to the following public key(s): Usernamefirstname.lastname@example.org (KeyType/Size) OR X Unknown Key(s) It is not possible to decrypt this message because your keyring does not contain usable private key(s) corresponding to any of the above public key(s).
This error is caused by one of the following scenarios:
- The sender has not used the correct public key to encrypt the message/file. You will need to provide the sender with the correct public key. This public key must correspond to a key pair on the machine you are using to decrypt the message/file. This means you would have exported the public portion of the key pair and sent it to your contact. The contact would have encrypted using that public key. When the message is then received, the key pair will be used to decrypt the file, provided the correct passphrase is entered.
- The sender has used your public key to encrypt the message/file, but you no longer have the matching keypair on your system. This might occur if you have recently formatted your computer, and did not save backups of your previous keyrings. When you reinstall PGP, a new keypair is generated and it is necessary to provide the sender with your new public key.