How to Find PGP Signatures

Pretty Good Privacy (PGP) is used to exchange encrypted text.

Pretty Good Privacy (PGP) is a popular public key encryption system used on the Internet. PGP encryption employs the use of a pair of encryption and decryption keys, one public and one private. Messages encrypted by one key of a PGP key pair can only be decrypted by the other key of the pair. The system allows the PGP keypair owner to exchange privately-encrypted messages with anyone who has a copy of the public key. You can use PGP-encrypted signatures to find out if the sender of a message is authentic.

Instructions

1. Download the latest version of PGP from http://www.pgpi.org/download/. Select the version appropriate for your location and your computer system. Install the file on your computer.

2. Review the e-mail or document you wish to verify. A line above the text should state that it is linked to a PGP signature. The PGP signature is included at the bottom as a block of text composed of letters and numbers that appear to be random.

3. Locate the sender's public PGP key. If you do not already have a copy of the sender's public key, you may need to locate it in another e-mail, on a web page, or contact the sender directly.

4. Open the PGP program you downloaded. Copy and paste the sender's public key and the PGP-encrypted signature block into the PGP program. If the PGP signature cannot be verified, attempt copying it again, taking care to preserve the original formatting.

5. Repeat the verification process for each e-mail or document separately. PGP signatures are created individually and cannot be reused.

Tips & Warnings

• Some e-mail programs may already have software in place to automatically encrypt or decrypt PGP messages or signatures. Review your e-mail program's documentation to find out if you can verify PGP signatures using your e-mail program.

• Be careful to preserve the format of any PGP encrypted signature, message or key. Successful encryption and decryption require that the format of the text not be altered.

References

• International PGP: How PGP Works
• Maximum RPM: An Introduction to PGP
• UBC Theoretical Physics: PGP for Beginners
• Tom McCune: PGP Questions & Answers