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package zeroecho.core.alg.ed25519;

import zeroecho.core.spec.AlgorithmKeySpec;

/**
 * <h2>Specification for Ed25519 key-pair generation</h2>
 *
 * Marker {@link zeroecho.core.spec.AlgorithmKeySpec} used to request generation
 * of Ed25519 key pairs.
 *
 * <p>
 * Ed25519 has no tunable domain parameters (e.g., key size or curve options).
 * Therefore, this spec acts as a simple token to identify the algorithm when
 * invoking key generation. All instances are equivalent; applications should
 * typically use {@link #defaultSpec()}.
 * </p>
 *
 * <h2>Usage example</h2> <pre>{@code
 * // Generate a new Ed25519 key pair using the default spec
 * KeyPair kp = session.keyBuilders().asymmetric()
 *     .generateKeyPair("Ed25519", Ed25519KeyGenSpec.defaultSpec());
 * }</pre>
 *
 * <h2>Thread-safety</h2> The default spec instance is immutable and safe to
 * reuse across threads.
 *
 * @since 1.0
 */
public final class Ed25519KeyGenSpec implements AlgorithmKeySpec {
    private static final Ed25519KeyGenSpec DEFAULT = new Ed25519KeyGenSpec();

    /**
     * Returns the canonical, shared default spec instance for Ed25519 key
     * generation.
     *
     * <p>
     * Since Ed25519 has no configurable parameters, this singleton should be used
     * for all generation requests. Applications may still construct additional
     * instances, but they are functionally identical.
     * </p>
     *
     * @return the default Ed25519 key generation spec
     */
    public static Ed25519KeyGenSpec defaultSpec() {
        return DEFAULT;
    }
}
