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package zeroecho.core;

/**
 * High-level classification of cryptographic algorithms.
 * <p>
 * Each {@code AlgorithmFamily} groups primitives with similar lifecycle
 * constraints, key properties, and safe usage patterns.
 *
 * <h2>Families</h2>
 * <ul>
 * <li>{@link #ASYMMETRIC}: Public-key algorithms such as signature schemes
 * (Ed25519, RSA) or public-key encryption.</li>
 * <li>{@link #SYMMETRIC}: Shared-key algorithms such as block/stream ciphers
 * and message authentication codes.</li>
 * <li>{@link #KEM}: Key encapsulation mechanisms, including post-quantum
 * schemes.</li>
 * <li>{@link #DIGEST}: Unkeyed hash functions and extendable-output functions
 * (e.g., SHA-2, SHA-3, BLAKE3).</li>
 * <li>{@link #AGREEMENT}: Key-agreement schemes (e.g., X25519, ECDH), distinct
 * from KEMs but with similar goals.</li>
 * </ul>
 *
 * <p>
 * <b>Usage:</b> Libraries and protocols can branch on this classification to
 * enforce correct API surfaces (e.g., demanding nonces for symmetric AEAD, or
 * key pairs for asymmetric operations).
 * </p>
 *
 * @since 1.0
 */
public enum AlgorithmFamily {
    /** Public-key primitives (signatures, RSA, etc.). */
    ASYMMETRIC,
    /** Shared-key primitives (ciphers, MACs). */
    SYMMETRIC,
    /** Key encapsulation mechanisms (encapsulate/decapsulate). */
    KEM,
    /** Unkeyed hash functions or XOFs. */
    DIGEST,
    /** Key-agreement schemes such as ECDH/X25519. */
    AGREEMENT
}
