Public key cryptography is a security technique that uses a pair of public and private keys for encrypting and decrypting data. It allows you to securely exchange information over the Internet, ensuring your communications and data are protected from unauthorised access.
The invention of public key cryptography has been a game-changer for businesses. As a core component of Public Key Infrastructure (PKI), it enables the creation and management of digital certificates, which verify the authenticity of users and devices in your network.
In this guide, we explain who invented public key cryptography. Keep your security up to date with the latest methods by choosing Nexus Smart ID PKI, a comprehensive encryption and authentication solution for modern businesses.
The problems with secure communications before public key cryptography
Private key cryptography, or symmetric cryptography, was predominantly used before the invention of public key cryptography. In symmetric cryptography, the same private key is used for both encryption and decryption of data.
With this method, you and your recipient must exchange this secret key before you can communicate safely. This presents challenges for large-scale or long-distance communication.
- Key exchange: Exchanging keys securely can be difficult. You must find a way to share the key with your recipient without it being intercepted by a third party. This is especially challenging over long distances or untrusted networks.
- Key management: In symmetric cryptography, you need a unique key for every communication pair. Managing these keys becomes complex as the number of users increases. This makes it difficult to scale secure communications across large organisations.
The Enigma machine used by the Germans during World War II demonstrates the challenges of symmetric key cryptography. This machine used an early example of the symmetric key system, where both the sender and receiver needed to use the same settings to encrypt and decrypt messages. These settings were typically changed daily based on secret key books.
Despite its complexity, the code was eventually broken by Allied cryptanalysts. The reliance on daily key changes and physical key books made the system vulnerable to interception. Once the Allies obtained the key books, they could decrypt the messages.
The birth of public key cryptography
The limitations of symmetric key cryptography drove the need for a more secure solution. The concept of public key cryptography, or asymmetric cryptography, was introduced in 1976 by Whitfield Diffie and Martin Hellman. Their groundbreaking paper, “New Directions in Cryptography,” presented the idea of asymmetric encryption, which allowed secure communication without private key exchange.
Public key cryptography uses a pair of keys: one public and one private. You use the public key to encrypt a message, and only the recipient’s private key can decrypt it. This method ensures safe and inaccessible sharing of data or messages without needing to share the private key.
The introduction of public key cryptography was a major milestone in the field. It addressed the key distribution problem, making it easier to secure communications over the Internet. This innovation created new possibilities for secure communication in the digital age.
The inventors and contributors of public key cryptography
There are a few key figures who contributed to the development and popularisation of public key cryptography. Their collective efforts transformed theoretical concepts into practical solutions that are integral to PKI security.
Whitfield Diffie and Martin Hellman
Whitfield Diffie and Martin Hellman are widely regarded as the pioneers of public key cryptography. Their collaboration led to the development of the Diffie-Hellman key exchange protocol. This was a mathematical method to securely exchange cryptographic keys over an insecure channel.
Diffie and Hellman’s work was inspired by the need for a secure method of key exchange. Their innovative approach to cryptography laid the groundwork for subsequent developments in the field. Their contributions earned them numerous accolades and cemented their place in the history of cryptography.
Ralph Merkle
Ralph Merkle was also instrumental in the development of public key cryptography. He developed a cryptographic system known as Merkle’s Puzzles. Merkle’s Puzzles demonstrated that it was possible to exchange cryptographic keys securely even if the communication channel was not secure.
Here’s a simple explanation of how Merkle’s Puzzles work:
- Puzzle creation: The sender, usually named Alice, creates many puzzles. Each puzzle consists of an encrypted message containing a secret key and a puzzle identifier. The puzzles are designed to be difficult and time-consuming to solve without the correct key.
- Puzzle distribution: Alice sends all the puzzles to the receiver, typically named Bob. The puzzles are transmitted over an insecure channel.
- Puzzle-solving: Bob randomly selects and solves one of the puzzles. Solving the puzzle reveals the secret key and the puzzle identifier.
- Key transmission: Bob sends the puzzle identifier back to Alice, indicating which puzzle he solved.
- Key verification: Alice uses the puzzle identifier to find the corresponding secret key. Alice and Bob now share the same secret key without it being directly transmitted over the insecure channel.
The RSA Algorithm
The RSA algorithm, named after its inventors Ron Rivest, Adi Shamir, and Leonard Adleman, is one of the most widely used public key cryptosystems. Developed in 1977, RSA is based on the use of large prime numbers for encryption and decryption.
RSA’s strength comes from the difficulty of factoring large composite numbers. This property makes it computationally infeasible for an attacker to derive the private key from the public key. RSA is widely used for securing internet communications, like SSL/TLS for web traffic and digital signatures for verifying documents.
The development of RSA was a breakthrough in public key cryptography. It provided a practical and strong method for secure communication. This paved the way for the widespread use of PKI systems.
The GCHQ Revelation
In 1997, it was revealed that the British intelligence agency GCHQ had independently discovered public key cryptography concepts before Diffie and Hellman. This was a result of the collaborative work between James Ellis, Malcolm Williamson, and Clifford Cocks. However, their work remained classified and was not shared with the public or the broader cryptographic community.
FAQs about public key cryptography
Did GCHQ invent RSA?
No, GCHQ did not invent RSA. The RSA algorithm was developed by Ron Rivest, Adi Shamir, and Leonard Adleman. GCHQ’s work remained classified and did not influence the development of RSA.
Who are the most famous people in cryptography?
Some of the most famous people in cryptography include Whitfield Diffie, Martin Hellman, Ralph Merkle, Ron Rivest, Adi Shamir, and Leonard Adleman. These individuals made significant contributions to the development of public key cryptography.
Who is the owner of public key?
The owner of a public key is the individual or entity who holds the corresponding private key. The public key is shared openly, while the private key stays confidential and is used to decrypt messages encrypted with the public key.