Symmetric encryption and asymmetric encryption are the two primary types of cryptographic algorithms. Symmetric encryption, such as the Advanced Encryption Standard (AES), uses the same key for both encryption and decryption. It is efficient for processing large amounts of data but requires secure key management. Asymmetric encryption, like RSA, uses a pair of keys: a public key for encryption and a private key for decryption. This method simplifies key distribution and is widely used in digital signatures and secure communications.

Hash functions and elliptic curve cryptography (ECC) are critical techniques within cryptographic algorithms. Hash functions generate a fixed-size hash value from input data, ensuring data integrity by enabling the detection of alterations. ECC, on the other hand, offers security through smaller key sizes compared to traditional algorithms, making it efficient for mobile and embedded devices.

Cryptographic algorithms are integral to various applications and protocols. Stream ciphers and block ciphers are methods used to encrypt data streams and fixed-size blocks of data, respectively. Digital signatures use asymmetric encryption to verify the authenticity of digital messages or documents. Public Key Infrastructure (PKI) manages keys and certificates, ensuring secure electronic transactions. End-to-end encryption guarantees that data is encrypted on the sender's side and only decrypted on the recipient's side, protecting communications from intermediaries.