Cryptography Questions Long
Public Key Infrastructure (PKI) is a system that enables secure communication and authentication over a network. It is a framework that consists of hardware, software, policies, and procedures to manage digital certificates and public-private key pairs. PKI plays a crucial role in cryptography by providing a secure and reliable way to encrypt and decrypt data, verify the authenticity of digital signatures, and establish secure communication channels.
The main components of a PKI system include a Certification Authority (CA), Registration Authority (RA), Certificate Repository, and end entities (users or devices). The CA is responsible for issuing and managing digital certificates, which are electronic documents that bind a public key to an entity's identity. The CA verifies the identity of the entity before issuing the certificate, ensuring the integrity and authenticity of the public key.
The RA acts as an intermediary between the CA and the end entities, assisting in the verification process and managing certificate requests. The Certificate Repository stores and distributes the issued certificates, allowing users to access and verify the authenticity of public keys.
PKI utilizes asymmetric cryptography, also known as public-key cryptography, which involves the use of two mathematically related keys - a public key and a private key. The public key is freely distributed and used for encryption, while the private key is kept secret and used for decryption. This ensures that only the intended recipient, who possesses the corresponding private key, can decrypt the encrypted data.
In the context of PKI, an entity can encrypt data using the recipient's public key, ensuring confidentiality during transmission. The recipient can then decrypt the data using their private key, which is securely stored and known only to them. This process provides secure communication channels, protecting sensitive information from unauthorized access.
PKI also plays a vital role in digital signatures, which provide integrity and non-repudiation. A digital signature is created by encrypting a hash value of the data using the sender's private key. The recipient can verify the signature by decrypting it with the sender's public key and comparing the decrypted hash value with the calculated hash value of the received data. If they match, it ensures the integrity of the data and verifies the authenticity of the sender.
Overall, PKI establishes a trusted infrastructure for secure communication, authentication, and data integrity. It enables the secure exchange of information over networks, protects against unauthorized access, and ensures the authenticity and integrity of digital transactions.