Asymmetric cryptography has revolutionised the security of communications over insecure networks. It provides a robust method within your Public Key Infrastructure (PKI) framework for protecting data and ensuring privacy. With this encryption method, you can keep your sensitive information secure from cyber threats.
In this guide, we explore what is asymmetric key cryptography, how it works, and its importance for business owners looking to enhance IoT security. With Nexus Smart ID PKI, you can further strengthen your security infrastructure and ensure seamless, secure communication within your organisation.
What is asymmetric cryptography?
Asymmetric cryptography, also known as public key cryptography, is a method of encryption that uses a pair of mathematically related public and private keys. The public key is openly shared and used to encrypt the message by turning the plaintext into ciphertext. The private key, which is kept secret, is used to return the ciphertext to plaintext.
Why is asymmetric cryptography important?
Asymmetric cryptography ensures that sensitive information can be encrypted and decrypted securely, providing a high level of trust. This encryption method is crucial for protecting communications, IoT devices, and digital transactions within your business.
Enhanced security
Asymmetric cryptography provides a high level of security by using two separate keys for encryption and decryption. This ensures that even if the public key is compromised, the private key remains secure, protecting sensitive information.
Secure key distribution
The invention of public key cryptography addressed the limitations of symmetric cryptography. With symmetric cryptography, the same private key is used for both encryption and decryption. Asymmetric cryptography eliminates the challenges of securely sharing the private key by using separate keys for encryption and decryption.
Digital signatures
Asymmetric cryptography works within the PKI framework by allowing you to issue digital certificates that verify the authenticity of public keys. These certificates help establish trust between parties communicating over insecure networks, such as the Internet.
IoT infrastructure security
Asymmetric cryptography provides a secure IoT infrastructure. It ensures that sensitive information can be transmitted securely between IoT devices without the risk of interception.
How does asymmetric cryptography work?
Here’s a deeper look at how asymmetric cryptography works:
1. Key generation
The first step in asymmetric cryptography is generating a pair of keys: a public key and a private key. This is done using complex mathematical algorithms, such as the RSA (Rivest-Shamir-Adleman) algorithm. The keys are mathematically linked, but it is computationally infeasible to derive the private key from the public key.
2. Key distribution
Once the key pair is generated, the public key can be freely distributed to anyone who needs to send you encrypted messages. The private key must be kept confidential. This distribution allows secure communication without needing to share a single secret key, like with symmetric encryption.
3. Encryption
When someone wants to send you a secure message, they use your public key to encrypt the data. This ensures that only you can decrypt and access the message with the corresponding private key.
4. Decryption
When you receive the encrypted message, you use your private key to decrypt it. The private key is designed to reverse the encryption process applied by the public key. Only the private key can decrypt the message, ensuring that the communication remains confidential and secure.
How are asymmetric encryption and symmetric encryption used for TLS/SSL?
Secure Sockets Layer (SSL) and its successor Transport Layer Security (TLS) are protocols designed to provide secure communication over the Internet. They use a combination of asymmetric and symmetric encryption to ensure both security and efficiency.
Asymmetric cryptography to establish a secure connection
When a client, such as a web browser, connects to a server, like a website, the initial step involves establishing a secure connection using asymmetric encryption. This process, known as the SSL/TLS handshake, involves these steps:
- Client Hello: The client sends a “Client Hello” message to the server, which includes information about supported encryption algorithms and a randomly generated number.
- Server Hello: The server responds with a “Server Hello” message, selecting an encryption algorithm and sending its digital certificate. This certificate contains the server’s public key and is signed by a trusted Certificate Authority (CA).
- Certificate Verification: The client verifies the server’s digital certificate using the CA’s public key. If the certificate is valid, the client trusts the server’s public key.
- Premaster Secret: The client generates a premaster secret, encrypts it with the server’s public key, and sends it to the server. Only the server can decrypt this secret with its private key.
- Session Keys Created: Both the client and server use the premaster secret to generate symmetric session keys for encryption and decryption of data.
- Client is Ready: The client sends a message indicating it is ready to start encrypted communication using the session keys.
- Server is Ready: The server responds, confirming it is also ready to start encrypted communication.
- Secure Symmetric Encryption: All data transferred between the client and server is encrypted using symmetric encryption.
Symmetric cryptography for efficiency
Asymmetric encryption is computationally intensive and slower than symmetric encryption. It is used only during the initial handshake to securely exchange the session key. Once the session key is established, symmetric encryption takes over for the actual data transfer, providing a faster and more efficient way to maintain the confidentiality and integrity of the communication.
FAQs about asymmetric encryption
What is the biggest weakness of asymmetric cryptography?
Encrypting and decrypting data using asymmetric algorithms requires significant processing power and time compared to symmetric cryptography.
What is an example of asymmetric encryption?
An example of asymmetric encryption is the RSA algorithm. RSA (Rivest-Shamir-Adleman) is widely used for secure data transmission. It relies on the mathematical properties of large prime numbers to generate public and private key pairs. RSA is used in web browsers, secure emails, and other communication channels.
Is the Caesar cipher symmetric or asymmetric?
The Caesar cipher is a symmetric encryption method. The Caesar cipher is a simple substitution encryption technique where each letter in the plaintext is shifted a fixed number of places down the alphabet.