Block Cipher
A block cipher is a symmetric-key cryptographic algorithm that encrypts fixed-length groups of bits, called blocks, using a secret key. It operates by taking a plaintext block and transforming it into a ciphertext block of the same size through a series of substitution and permutation operations. Block ciphers are fundamental to data encryption in protocols like AES and DES, providing confidentiality for secure communications and storage.
Developers should learn block ciphers when implementing encryption for sensitive data, such as in secure messaging apps, financial transactions, or database protection, as they offer robust security against unauthorized access. They are essential for compliance with standards like PCI-DSS or GDPR, and understanding them helps in selecting appropriate algorithms (e.g., AES for high security) and avoiding vulnerabilities like padding oracle attacks.