View Key Pair Details

You can view the details of a key pair by right-clicking on the key pair in the key toolbox or key management interface and selecting “Show key details”.

This section may include a brief introduction to gpg-related concepts and could be relatively long.

Here is a randomly generated private key. The most significant difference between this and the previous key is that the key pair with only the public key is used for encryption only, but if you possess the private key, you can perform more actions (it also depends on your algorithm; DSA can only be used for signatures).

General Info

This interface provides some useful information to help you manage your key pair properly.

Owner

This section enables you to know the owner of this key pair. This information is not fixed and can be changed. You can create a new UID in the UID section and set it as the primary UID to change it.

According to the OpenPGP protocol, this part is divided into Name, Email, and Comment.

Primary Key

This part is the information of the primary key of the key pair. The primary key is very crucial because without it, you cannot perform related management operations like adding and revoking sub-keys (similar to not being able to open the key ring). Let’s introduce the information of the primary key separately below. If you want to learn more, see the Fundamental Concepts section.

The absence of the master key means that the private key of the master key does not exist, but this doesn’t mean that neither the public key nor the private key exists. Please remember: Each subkey and primary key consist of a pair of public and private keys.

Key ID

This is the unique identifier of the key, which is fixed and unchanging. Note that this key ID is the key ID of the primary key. The key ID is uniquely determined after the key is generated. Compared with the fingerprint, the key ID is shorter and more user-friendly.

Algorithm

This refers to the algorithm used for key generation. This also pertains to the generation algorithm of the primary key. The generation algorithm determines the properties and capabilities of the key. Algorithms such as RSA can be used for both encryption and signatures, whereas DSA can only be used for signatures. More modern algorithms like ECDH (Elliptic-curve Diffie-Hellman) are used for secure key exchange, and ECDSA (Elliptic Curve Digital Signature Algorithm) is employed for digital signatures. These elliptic curve algorithms offer enhanced security with shorter key lengths compared to traditional algorithms.

Algorithm Detail

Algorithm Detail displays both the key type and the key length. In some cases, the key algorithm shown here is more precise. For example, it can specify particular algorithms such as ED25519 or NISTP256, providing detailed information about the specific cryptographic methods employed.

Key Size

This is the length of the primary key. Generally, the longer the key, the harder it is to crack the ciphertext. But at the same time, it takes more time for a single operation. Generally speaking, a length of 2048 bits is safe enough (this refers to the key generated using the RSA algorithm).

Normal Usage

This refers to what the key pair can conceptually be used for, including the conceptual usage of the primary key and sub-key. When the primary key or subkey generation can be used to sign, but it has already expired or does not exist, the signature usage will still be displayed here.

Actual Usage

This is the actual usage of the primary key and all subkeys, which is the union of their usage. If there is only one primary key in the key pair that can be used for signing, but this primary key does not exist, then the signature usage will not appear here, only in Normal Usage. In addition, when there is only one subkey that can be used for signing, if it has expired, the signature purpose will not be displayed here.

Expires on

This is the expiration time of the primary key. When the primary key expires, it will become invalid and you can’t use it for any operation. In addition, the subkeys in the key pair will also be unavailable. Fortunately, you can change the expiration time of the primary key at any time, or even set it to never expire. The prerequisite for this is that the primary key exists in the key pair.

Last Update

This is the time when the content of the key pair was last updated. Operations such as adding a UID or subkey will modify the content of the key pair.

Secret Key Existence

This indicates whether the actual content of the primary key exists. When the primary key does not exist, if there are still available subkeys in the key pair, the key pair can still be used for normal operations. However, in the above case, the content of the key pair cannot be modified (that is, operations such as adding UID or subkey cannot be performed), and the key pair cannot sign other key pairs.

Fingerprint

The fingerprint of the key pair is used for humans to quickly compare whether the key pair is the expected key pair. This field is unique for all keys in the world. You can certainly do this with the key ID mentioned above.

This also refers to the fingerprint of the primary key.

UID Info

User ID (UID) is used to identify a key, mainly for human identification. It’s similar to a name tag that accompanies a key ring, indicating who the key ring belongs to. By looking at the UID, users can get a rough idea of whether a key pair is what they expected. However, for accurate identification, fingerprints or key IDs should be compared. A key can have multiple UIDs, but a key pair can only have one primary UID, which is always listed first in the interface.

UID has three elements: Name, Email, Comment. The name should be at least five characters long, and the email should conform to the format. The rules for comments are relatively loose.

Signature of UID

The lower section of the interface displays the signature of the selected User ID (UID), not the checked one. This is a key trust system. When someone receives your public key, they can use their private key to sign your nameplate, indicating their recognition of your public key. Afterward, they can upload the keyring with their signature to the keyserver. If many people do the same, the public key on the keyserver will have numerous signatures, making it trustworthy.

You can also use the primary key of another key pair to sign a UID. Generally, a primary UID of a key pair with many valid signatures is considered more trustworthy.

As shown in the image, some signatures do not have the signer’s UID identified. If you need to identify these signatures, you can try importing the corresponding key from other sources, such as key servers. The Key ID is already provided, which can help you locate and import the necessary keys to recognize the signer’s UID.

Subkey Info

The sub-key mechanism is a crucial feature of GPG that improves both flexibility and security. However, it also introduces some complexity, which can be challenging for beginners. For a basic understanding, consider the following points:

• A key pair can be likened to a key ring, comprising a primary key (a pair of public and private keys) and multiple subkeys (or none).
• Each subkey and primary key consists of a pair of public and private keys.
• The subkey can perform related operations (such as signing, encryption) in the absence or unavailability of the primary key.
• The functions of subkeys can overlap, and when both subkeys can be used for signing, the earlier one is selected.
• Subkeys can use more algorithms than the primary key, but usually have the same effect on daily operations.
• The disclosure of a subkey only affects that subkey, while the disclosure of the primary key endangers the entire key pair.

The primary key and all subkeys in the key pair are displayed on the interface. Some information about the key is also listed below.

Key In smart card

Whether a key is in the smart card refers to whether the key is moved to the smart card. Moving the key to the smart card changes the structure of the key and is irreversible.

Operations

In this column, what you can do differs for a key pair that only has a public key and a key pair that includes a private key.

Operations on a Public Key

This interface provides various general operations that can be performed on the selected public key. Below is an explanation of each button’s function:

1. Export Public Key:

   • Function: This button allows you to export the public key to a file. Exporting a public key is useful when you need to share it with others or upload it to a keyserver. The exported file can then be distributed or backed up as needed.

2. Key Server Operation (Pubkey):

   • Function: This dropdown menu provides options for interacting with keyservers. A keyserver is a repository where public keys are stored and can be retrieved by others. The operations might include uploading your public key to a keyserver, refreshing your public key with updates from the keyserver, or searching for other public keys on the keyserver.

3. Set Owner Trust Level:

   • Function: This button allows you to set the trust level for the owner of the public key. Trust levels are part of the web of trust model used in public key infrastructures. By setting the trust level, you indicate how much you trust the key owner to correctly verify and sign other keys. This affects how your system evaluates the validity of signatures made by the key owner.

These operations facilitate the management and sharing of public keys, helping to establish and maintain trust within a cryptographic system.

Operations on a Private Key

This interface provides various general operations that can be performed on the selected key pair, including both public and private key operations. Below is an explanation of each button’s function:

1. Export Public Key:

   • Function: This button allows you to export the public key to a file. This is useful for sharing your public key with others or for uploading it to a keyserver. The exported file can be distributed or backed up as needed.

2. Export Private Key:

   • Function: This button provides options for exporting the private key. There are typically two modes for exporting:
     • Export Complete Private Key: This exports the entire private key, including all associated information. It is used when you need a full backup or when transferring the key to another system.
     • Export Minimal Private Key: This exports only the essential components of the private key, minimizing the amount of data. This can be useful for more secure key transfers or for environments with specific security requirements.

3. Modify Expiration Datetime (Primary Key):

   • Function: This button allows you to modify the expiration date and time of the primary key. This is important for managing the key’s lifecycle and ensuring that it remains valid for the desired period. Adjusting the expiration date can help maintain security by ensuring keys are periodically reviewed and updated.

4. Modify Password:

   • Function: This button enables you to change the password that protects the private key. Changing the password can enhance security, especially if you suspect that the current password may have been compromised or if you want to follow best practices for regular password updates.

5. Key Server Operation (Pubkey):

   • Function: This dropdown menu provides options for interacting with keyservers using the public key. Operations might include uploading the public key to a keyserver, or refreshing the key from the keyserver. Keyservers facilitate the distribution and retrieval of public keys.

6. Revoke Certificate Operation:

   • Function: This dropdown menu provides options for generating a revocation certificate for the key or importing an existing revocation certificate. Revoking a certificate is necessary if the key has been compromised or is no longer needed. This action invalidates the key, ensuring it cannot be maliciously used. Revocation information is typically uploaded to a keyserver to inform others about the revoked status of the key.

These operations help manage the lifecycle of key pairs, ensuring their secure use and proper distribution.