[Java executable commands] (11) Java keystore and certificate management tool keytool: play with keystore and certificate management, and deeply analyze the application and skills of keytool tools~

keytool for Java executable commands

1 concept
2 Advantages and disadvantages
3 use
- 3.1 Syntax format
- 3.2 Generate a certificate request: keytool -certreq
- 3.3 Export certificate: keytool -exportcert
- 3.4 Generate a key pair: keytool -genkeypair
- 3.5 Import certificate or certificate chain: keytool -importcert
- 3.6 List the entries in the keystore: keytool -list
4 Application scenarios
5 Use skills
Summarize

1 concept

Java’s keytool command is a tool for managing and operating the Java keystore (KeyStore). It is designed to facilitate Java developers to generate, manage, and manipulate digital certificates, and to implement encryption and authentication for secure access to protected resources.

Some related concepts?
Keystore (KeyStore): It is a container for storing keys and certificates, which can contain private keys, public keys, trusted certificates and root certificates, etc.;
Key Pair: A pair of associated keys, including a private key and a corresponding public key;
Digital Certificate: A digitally signed file containing public key information and holder identity information issued by a certificate authority (CA).

The keytool command can be used to: generate and manage key pairs and digital certificates, import and export keys and certificates in the key store, list key and certificate information in the key store, issue and verify digital certificates, and support the use of multiple encryption algorithms and key lengths.

The bottom layer of the keytool command is implemented using the keystore-related API provided by Java. It can interact with different types of keystores, and provides functions such as generating, importing, exporting, signing, and verifying keys and certificates. The specific implementation principle involves details related to keystore format and encryption algorithm.

2 Advantages and disadvantages

Benefits:

Easily generate and manage key pairs and digital certificates;
Provides strong encryption and authentication functions to ensure data security and integrity;
Support multiple encryption algorithms and key lengths, providing flexibility;
Supports many different types of keystores (such as JKS, PKCS12, etc.) for storage and operation.

Disadvantages:

The command line interface is complex and requires familiarity with its syntax and parameters. A certain understanding of the concepts of keys and certificates is required for proper use and operation.

3 Use

3.1 Grammar format

The following is the basic syntax of the keytool command:

keytool [-command_name] [command] [parameters]

Among them, -command_name represents various types of operation commands, and [command] [parameter] represents the optional parameters of a specific -command_name operation. The various operation commands supported by keytool are summarized as follows:

Import a certificate or certificate chain

Command	Description
`-certreq`	Generate Certificate Request
`-changealias`	Change Entry Alias
`-delete`	delete entry
`-exportcert`	export certificate
`-genkeypair`	Generate key pair
`-genseckey`	Generate key
`-gencert`	Generate certificate based on certificate request
`-importcert`
`-importpass`	Import a password
`-importkeystore`	Import one or all entries from another keystore
`-keypasswd`	Change key password for entry
`-list`	List entries in keystore
`-printcert`	Print certificate content
`-printcertreq`	Print the content of the certificate request
`-printcrl`	Print the content of the CRL file
`-storepasswd`	Change the storage password of the keystore

From the information above, we can see that the keytool command has comprehensive support for various operations on key pairs, certificates, and keystores. Readers can also refer to the table to select the required operation commands according to their own needs. The following mainly introduces some commonly used command operations:

-certreq: generate a certificate request;
-exportcert: export certificate;
-genkeypair: generate a key pair;
-importcert: import certificate or certificate chain;
-list: List the entries in the keystore.

For commands not introduced, you can use “keytool -command_name -help” to get the usage of the command corresponding to the command_name.

3.2 Generate certificate request: keytool -certreq

The keytool -certreq command is used to generate a Certificate Signing Request (CSR) to send to a Certificate Authority (CA) for a trusted digital certificate.

The usage is:

keytool -certreq [OPTION]...

Among them, [OPTION] indicates optional parameters, and all parameters are summarized as follows:

parameter	description
`-alias`	alias of the entry to process
`-sigalg`	signature algorithm name
`-file`	Output file name
`-keypass`	key password
`-keystore`	keystore name
`-dname`	unique distinguished name
`-storepass`	keystore password
`-storetype`	keystore type
`-pro providername`	provider name
`-providerclass`	provider class name
`-providerarg`	provider parameter
`-providerpath`	Provider class path
`-v`	Verbose output
`-protected`	Password via protected mechanism

Here is an example usage:

keytool -certreq -alias myalias -file csrfile.csr -keystore mykeystore.jks

In this command, the -certreq parameter means to generate a certificate request, and the alias (myalias), the output file path (csrfile.csr) and the keystore path (mykeystore.jks) need to be provided.

Execute the above command, the keytool tool will generate a certificate request file (CSR) according to the given alias and keystore. This file contains the public key in the key pair and associated identity information such as country, organization, and common name. The CSR can be sent to a certificate authority to issue digital certificates.

Certificate requests can be easily created by using the keytool -certreq command in order to obtain a trusted digital certificate issued by a CA. This is an important step in establishing trust relationships with external entities for secure communication and authentication.

3.3 Export certificate: keytool -exportcert

keytool -exportcert command is used to export a digital certificate from a key store (KeyStore).

The usage is:

keytool -exportcert [OPTION]...

Among them, [OPTION] indicates optional parameters, and all parameters are summarized as follows:

Parameter	Description
`-rfc`	Output in RFC style
`-alias`	Alias of the entry to process
`-file`	output filename
`-keystore`	keystore name
`-storepass`	keystore password
`- storetype`	keystore type
`-providername`	provider name
`-providerclass`	provider class name
`-providerarg`	provider arguments
`-providerpath`	provider classpath
`-v`	verbose output
`-protected`	Password via protected mechanism

The following are usage examples and descriptions:

keytool -exportcert -alias myalias -file certfile.cer -keystore mykeystore.jks

In this command, the -exportcert parameter means to export the certificate, and you need to provide the alias (myalias), the output file path (certfile.cer) and the keystore path (mykeystore.jks).

Execute the above command, the keytool tool will export the digital certificate corresponding to the specified alias (myalias) according to the given alias and keystore, and save it as a .cer file (eg certfile.cer). The exported certificate file can be used for secure communication with other entities, authentication, etc.

By using the keytool -exportcert command, a digital certificate can be easily exported from a keystore for sharing or use with other entities. This helps to build reliable trust relationships and ensure secure communications.

3.4 Generate a key pair: keytool -genkeypair

keytool -genkeypair The command is used to generate a key pair (Key Pair), including a private key and a corresponding public key, and store it in the key store.

The usage is:

keytool -genkeypair [OPTION]...

Among them, [OPTION] indicates optional parameters, and all parameters are summarized as follows:

parameter	description
`-alias`	alias of the entry to process
`-keyalg`	key algorithm name
`-keysize`	Key bit size
`-sigalg`	Signature algorithm name
`-destalias`	Destination alias
`-dname`	Unique distinguished name
`-startdate`	Certificate validity start date/time
`-ext`	X.509 extension
`-validity`	Valid days
`-keypass`	Key password
`-keystore`	Keystore name
`-storepass`	keystore password
`-storetype`	keystore type
`-providername`	provider name
`-providerclass`	provider class name
`-providerarg`	provider parameter
`-providerpath`	provider class path
`-v`	verbose output
`-protected`	Password via protected mechanism

The following are usage examples and descriptions:

keytool -genkeypair -alias myalias -keypass mypassword -keystore mykeystore.jks

In this command, the -genkeypair parameter means to generate a key pair, and the alias (myalias), key password (mypassword) and keystore path (mykeystore.jks) need to be provided.

Execute the above command, the keytool tool will generate a new key pair according to the specified alias and keystore path, and store it in the keystore. A key pair usually consists of a private key for encryption and a public key for decryption.

By using the keytool -genkeypair command, a key pair can be generated and stored in a keystore for encryption, authentication, and secure communication. And keytool also provides other options and parameters, for example, you can use the -storepass option to specify the password of the keystore, and you can use the -keysize parameter to specify the length of the key.

3.5 Import certificate or certificate chain: keytool -importcert

The keytool -importcert command is used to import a digital certificate into a specific keystore. The usage is:

keytool -importcert [OPTION]...

Among them, [OPTION] indicates optional parameters, and all parameters are summarized as follows:

Parameter	Description
`-noprompt`	No prompt
`-trustcacerts`	Trust certificates from cacerts
`-protected`	Password via protected mechanism
`-alias`	alias of the entry to process
`-file`	input filename
`-keypass`	key password
`-keystore`	keystore name
`-storepass`	keystore password
`-store type`	keystore type
`-providername`	provider name
`-providerclass`	provider class name
`- providerarg`	provider parameter
`-providerpath`	provider class path
`-v`	verbose output

The following are usage examples and descriptions:

keytool -importcert -alias myalias -file certfile.cer -keystore mykeystore.jks

In this command, the -importcert parameter means to import the certificate, and you need to provide the alias (myalias), the path of the certificate file to be imported (certfile.cer), and the target keystore path (mykeystore.jks).

After executing the above command, the keytool tool will import the digital certificate in the specified file (such as certfile.cer) according to the given file path, and store it in the keystore. Imported digital certificates will be used for establishing trust relationships, secure communication, authentication, and more.

By using the keytool -importcert command, you can easily import digital certificates into a specified keystore and centrally manage all certificates required by your application.

3.6 List the entries in the keystore: keytool -list

The keytool -list command is used to list the certificates, private keys, and other related information in the keystore. The usage is:

keytool -list [OPTION]...

Among them, [OPTION] indicates optional parameters, and all parameters are summarized as follows:

-providerpath

Parameter	Description
`-rfc`	Output in RFC style
`-alias`	The alias of the entry to process
`-keystore`	keystore name
`-storepass`	keystore password
`-storetype`	keystore type
`-providername`	provider name
`-providerclass`	provider class name
`-providerarg`	provider parameters
Provider classpath
`-v`	Verbose output
`-protected`	Password via protected mechanism

The following are usage examples and descriptions:

keytool -list -keystore mykeystore.jks

In this command, the -list parameter means to list the contents of the keystore, and the keystore path (mykeystore.jks) needs to be provided.

After executing the above command, the keytool tool will display the certificate, private key and other related information in the specified keystore (eg mykeystore.jks), such as alias, creation date, etc.

By using the keytool -list command, you can easily view and verify the contents of the keystore to ensure that digital certificates and private keys are properly configured and managed.

4 Application scenarios

The keytool command plays an important role in the following scenarios:

Generation and management of digital certificates to verify identity and ensure communication security;
Generation and management of key pairs for encryption and decryption operations;
Creation and management of keystores to store and protect keys and certificates;
Issue digital certificate requests and import CA-signed certificates.

5 Tips

Learn and be familiar with the basic syntax and common options of the keytool command to ensure correct use;
Use appropriate algorithms and key lengths to generate and manage key pairs;
Use a different alias for each entity (application, user, etc.) for better identification and management;
Regularly back up and export the keystore to prevent key loss or damage;
Take care to set and protect the password of the keystore, and change the password regularly.

Summary

Java’s keytool command is a powerful and flexible tool for generating, importing, exporting, and managing key pairs and digital certificates. It provides a safe and reliable way for Java developers to protect application and data resources.

The security and integrity of keys and certificates can be ensured by following proper usage and handling practices. A solid understanding and mastery of keytool commands leads to better encryption, authentication, and data protection, and success in security awareness and practice.