GnuPG

GnuPG is a tool for secure communication. GnuPG uses public-key cryptography so that users may communicate securely. In a public-key system, each user has a pair of keys consisting of a private key and a public key. A user’s private key is kept secret; it need never be revealed. The public key may be given to anyone with whom the user wants to communicate. GnuPG uses a somewhat more sophisticated scheme in which a user has a primary keypair and then zero or more additional subordinate keypairs. The primary and subordinate keypairs are bundled to facilitate key management and the bundle can often be considered simply as one keypair.

Encrypting and decrypting documents

The GNU Privacy Handbook has a section Encrypting and decrypting documents.

Making and verifying signatures

The GNU Privacy Handbook has a section Making and verifying signatures.

My public key

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