In the IT world, certificates and certificate chains play a crucial role in establishing secure communications, verifying identities, and enabling secure authentication. Here's a simplified explanation of certificate chains and their use cases:
What are Certificates? Certificates are digital documents used to verify the identity of entities (e.g., websites, servers, individuals) and establish secure communication channels. They are issued and signed by Certificate Authorities (CAs) to vouch for the authenticity of the entity's identity.
What is a Certificate Chain? A certificate chain is a sequence of certificates, where each certificate in the chain is used to verify the authenticity of the next one. It starts with the end-entity certificate (e.g., website certificate) and links to an intermediate CA certificate, and potentially a root CA certificate.
Types of Certificates in a Chain:
a. End-Entity Certificate: This is the certificate of the entity you are interacting with, like a website's SSL/TLS certificate. It contains the entity's public key and is signed by an intermediate CA.
b. Intermediate CA Certificate: This certificate is signed by a root CA and is used to issue end-entity certificates. It establishes a trust chain between the root CA and the end-entity certificate.
c. Root CA Certificate: This is the top-level certificate in the chain. It is self-signed and serves as the ultimate trusted authority in the certificate hierarchy.
Use Cases in the IT World:
a. Secure Web Communication: Certificate chains are used in SSL/TLS to secure web communication. When you visit a website (e.g., example.com), your browser verifies the website's certificate by checking if it is signed by a trusted root CA.
b. Server Authentication: In server authentication, a server presents its certificate chain to the client, proving its identity. The client can verify the chain to ensure it's communicating with the genuine server.
c. Client Authentication: Similarly, in client authentication scenarios, the client presents its certificate chain to the server to prove its identity during a mutual TLS handshake.
d. Code Signing: Certificates are used for code signing to verify the authenticity and integrity of software and ensure it has not been tampered with.
e. VPN and Network Security: Certificate chains are used to authenticate VPN connections and secure communication between network devices.
f. Email Security: Certificates can be used for digitally signing and encrypting email messages, ensuring message integrity and privacy.
Public Key, Private Key, Public Certificate, and Private Certificate are cryptographic components used in various security protocols and encryption systems. Let's explore their use cases:
Public Key:
Use Case: Public keys are used in asymmetric encryption systems, such as RSA and ECDSA. They are shared openly and widely distributed to encrypt data that only the corresponding private key can decrypt.
Example Use Cases:
Secure Communication: Used to encrypt sensitive data transmitted over insecure networks like the internet. The encrypted data can only be decrypted by the recipient's private key.
Digital Signatures: Used in digital signatures to verify the authenticity and integrity of a message or document signed with the private key.
Private Key:
Use Case: Private keys are part of asymmetric encryption systems. They must be kept secret and never shared with others. Private keys are used to decrypt data encrypted with the corresponding public key and to create digital signatures.
Example Use Cases:
Decryption: Used to decrypt data encrypted with the corresponding public key. Only the private key owner can access the decrypted information.
Digital Signatures: Used to create a digital signature that can be verified using the corresponding public key, proving the authenticity of the signer.
Public Certificate:
Use Case: A public certificate is a digitally signed document that contains a public key and additional information about the certificate owner (such as organization details). It is used for authentication and data encryption.
Example Use Cases:
SSL/TLS Encryption: Used in HTTPS connections to encrypt data exchanged between the client and server. The web server presents its public certificate to the client during the SSL/TLS handshake.
Code Signing: Software developers use public certificates to sign their code, providing proof of the software's authenticity and integrity.
Private Certificate:
Use Case: Private certificates are generated in pairs with public certificates. The private certificate's corresponding private key must be kept secure and never shared.
Example Use Cases:
SSL/TLS Encryption: The private key associated with the SSL/TLS public certificate is used to decrypt data received from clients during the handshake process.
Code Signing: The private certificate's private key is used to sign software code, ensuring that it can be verified by the public certificate's public key.
- Widely used utilities for certificate management
openssl, keytool, and orapki are command-line tools used to manage certificates and cryptographic keys in different environments. While all three tools have similar purposes, they are specific to different platforms and technologies. Here's a brief overview of each tool and their correlation:
a. OpenSSL:
Purpose: OpenSSL is a widely used open-source software library that provides cryptographic functions and SSL/TLS protocols. It is highly versatile and supports various cryptographic operations, such as generating private keys, creating and signing certificates, and encrypting/decrypting data.
Platform: OpenSSL is available on various operating systems, including Unix-like systems, macOS, and Windows.
Use Cases: It is commonly used for SSL/TLS certificate management, creating certificate signing requests (CSRs), generating self-signed certificates, and more.
b. Keytool:
Purpose: Keytool is a command-line utility included in the Java Development Kit (JDK) and Java Runtime Environment (JRE). It is primarily used for managing Java Keystores, which are databases used to store cryptographic keys and digital certificates in Java-based applications.
Platform: Keytool is specific to Java-based environments and is included with the JDK/JRE installations.
Use Cases: Keytool is used to create and manage keystores, import and export certificates and keys, and set up SSL/TLS for Java applications.
c. Orapki:
Purpose: Orapki is a command-line tool provided by Oracle for managing security artefacts in Oracle environments. It is used for tasks related to managing Oracle wallets, including creating and managing certificates, private keys, and certificate signing requests.
Platform: Orapki is specific to Oracle environments, particularly when using Oracle wallets for secure authentication and encryption.
Use Cases: Orapki is commonly used to manage certificates and keys in Oracle wallets for securing Oracle databases, web applications, and other Oracle products.
- Truststore and keystore are two distinct concepts used in the context of SSL/TLS (Secure Socket Layer/Transport Layer Security) and cryptographic operations. Let's explore their differences:
Truststore:
- Purpose: A trust store is a repository that stores trusted certificates (public certificates) used to verify the authenticity of remote entities (such as servers) during SSL/TLS communication. It is used by clients (e.g., web browsers and applications) to determine which servers they can trust when establishing secure connections.
Keystore:
- Purpose: A keystore is a repository that stores private keys and their corresponding certificates (public certificates). It is used to identify the local entity (e.g., a server or a client) during SSL/TLS communication. Keystores are used by SSL/TLS servers and clients to present their public certificates and private keys during the handshake process.
- How to identify Secure and Insecure websites or URLs?
The main difference between a secure and an insecure website is the way that the data is transmitted between your browser and the website's server. A secure website uses HTTPS (Hypertext Transfer Protocol Secure), which encrypts the data so that it cannot be intercepted by third parties. An insecure website uses HTTP (Hypertext Transfer Protocol), which does not encrypt the data, making it vulnerable to interception.
Here are some of the other differences between secure and insecure websites:
URL: Secure websites have URLs that start with "https://" instead of "http://". The "s" stands for "secure".
Lock icon: Secure websites will have a lock icon in the address bar of your web browser. This indicates that the connection is encrypted.
Security certificate: Secure websites have a security certificate that verifies the identity of the website and ensures that the data is encrypted.
Risk of data theft: Insecure websites are more vulnerable to data theft, as the data is not encrypted. This means that your personal information, such as your username, password, and credit card details, could be intercepted by cybercriminals.
Here are some tips for staying safe on the internet:
Only visit secure websites.
Keep your software up to date.
Use a strong password and change it regularly.
Be careful about what information you share online.
Use a VPN (virtual private network) when you are using public Wi-Fi.
Certificate lifecycle
We will combine all the above-discussed utilities to understand the certificate lifecycle. This is what the flowchart of the certificate lifecycle looks like.
a. CSR ( Certificate Signing Request)
Note: We can start from step(a) if we don't have chain certificates otherwise skip to step (b) where we will have pfx and chain certificates.
keytool -genkey -alias <server> -keyalg RSA -keysize 2048 -keystore <keystore.jks>
keytool -certreq -alias <server> -keyalg RSA -file <domain_name.csr> -keystore <keystore.jks>
We will get a chain certificate from the CA authority. Let's take the example of instagram.com chain certificates
b. pfx to pem conversion
openssl pkcs12 -in <certificate.pfx> -out certificate.pem -nodes
c. pem to p12 conversion
openssl pkcs12 -export -in <certificate.pem> -inkey <certificate.pem> -out <certificate.p12> -name '<Alias name>'
d. To create a JKS certificate from step b
keytool -importkeystore -destkeystore <keystore.jks> -srckeystore <certificate.p12> -srcstoretype PKCS12 -alias '<alias name>'
e. Import chain certificates we received from certificate authority order of import will be root, intermediate and public certificate.
keytool -import -v -noprompt -trustcacerts -alias <alias name> -file <digicert_root.cer> -keystore <keystore.jks>
keytool -import -v -noprompt -trustcacerts -alias <alias name> -file <digicert_intermediate_ca.cer> -keystore <keystore.jks>
keytool -import -v -noprompt -alias <alias name> -file <digi_public.cer> -keystore <keystore.jks>
Note: Unique alias name we can give so that it can identify each certificate chain uniquely
f. To check the list of imported certificates
keytool -list -keystore <keystore.jks> -storepass <password>
g. If we are using Oracle HTTP Server (OHS) then we might come across a wallet. We can convert step (d) keystore certificate into wallet
orapki wallet jks_to_pcks12 -wallet <ohs_wallet> -pwd <changeit> -keystore <keystore.jks> -jkspwd <password>
Note: We can use any of the above certificates based on the application requirement.
Please feel free to reach out if you have any corrections or suggestions for my article. Thank you :)