Basics

Basic Concepts of Cryptography

Cryptography is a dynamic field that underpins secure communication and data protection. Here’s a breakdown of the key concepts you need to understand:

Plaintext and Ciphertext

  • Plaintext: The original, readable data or message before encryption.
  • Ciphertext: The scrambled, unreadable output of encryption, which can only be converted back to plaintext by decryption.

Encryption and Decryption

  • Encryption: The process of converting plaintext into ciphertext using an algorithm and a key. This ensures that the information remains confidential.
  • Decryption: The process of reversing encryption, transforming ciphertext back into readable plaintext using the same or a corresponding key.

Keys

  • Key: A secret value used in encryption and decryption. Keys are of two types:
    • Symmetric Key: The same key is used for both encryption and decryption, making the process straightforward but requiring secure key management.
    • Asymmetric Key: Utilizes a pair of keys—public for encryption and private for decryption—providing enhanced security for communication.

Algorithms

  • Algorithm: A set of mathematical rules used for encryption and decryption. Notable algorithms include RSA for asymmetric encryption, AES for symmetric encryption, and ECC for efficient, high-security cryptography.

Symmetric and Asymmetric Cryptography

  • Symmetric Cryptography: Employs a single key for both encryption and decryption. Examples include AES (Advanced Encryption Standard) and DES (Data Encryption Standard).
  • Asymmetric Cryptography: Utilizes two keys, one public and one private, to secure data. RSA (Rivest–Shamir–Adleman) and ECC (Elliptic Curve Cryptography) are popular examples.

Cryptographic Protocols

  • SSL/TLS: Protocols designed to secure communications over the internet, ensuring data integrity and confidentiality.
  • PGP: Used for securing email communications with encryption and digital signatures.
  • Blockchain: A decentralized protocol that secures transactions and records data in a tamper-evident manner.

Core Principles

  • Confidentiality: Ensures that information is only accessible to those who are authorized.
  • Integrity: Guarantees that data has not been altered or tampered with during transmission.
  • Authentication: Verifies the identities of the parties involved in the communication.
  • Non-repudiation: Ensures that a party cannot deny the authenticity of their actions or messages.

Understanding these basics provides a solid foundation for exploring more advanced cryptographic techniques and their applications in securing data and communications.

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