Cryptography is the practice and study of techniques for securing communication and data from third parties or adversaries. It involves converting information into a secure unreadable format, Ciphertext, then later restoring it to its original format, Plaintext using a secret key. Cryptography plays a crucial role in ensuring the confidentiality, integrity, and authenticity of information.
In programming, cryptography is used for various purposes:
Encryption and Decryption*:*
Encryption: This is the process of converting plaintext into ciphertext using an algorithm and key. The resulting ciphertext is typically unreadable without the correct key
Decryption: This is the reverse process of encryption. It involves converting ciphertext back into plaintext using the same algorithm and the correct key.
Symmetric Key Cryptography:
The same key is used for both encryption and decryption, just as a single key to a home can unlock and lock the same door.
This method is fast and efficient but the challenge lies in securely sharing the key between the sender and receiver
Asymmetric Key Cryptography:
Asymmetric Key Cryptography uses a pair of keys, a public key for encryption and a private key for decryption. It's like having a lock that can only be opened with a specific key but the key used to lock is different from the one used to unlock.
The public key can be freely shared, while the private key must be kept a secret. This method is often used for secure communication and digital signatures.
Hash Functions:
Hash Functions are a type of one-way function that takes an input (data) and produces a fixed-size string of characters, which is usually a hash value.
They are commonly used for creating checksums, verifying data integrity, and storing passwords securely.
Digital Signatures:
Digital Signatures are used to verify the authenticity and integrity of a message or document.
It involves using a private key to generate a unique digital signature which can be verified by anyone with the corresponding public key.
Secure Sockets Layer (SSL) / Transport Layer Security (TLS):
- SSL/TLS protocols are used to establish secure communication over the internet, ensuring that data transmitted between a user and a website is encrypted and protected from interception
Understanding these fundamental concepts can help developers implement cryptography effectively in their programs to secure sensitive information and communications.