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package zeroecho.pki.impl.framework.x509;

import java.util.Locale;
import java.util.Objects;

import zeroecho.core.spec.AlgorithmIdentity;

/**
 * Non-overridable PKI algorithm security floor.
 *
 * <p>
 * SHA-1 signatures, including RSA-PSS hash or MGF SHA-1, are rejected before
 * provider capability or configured policy is considered.
 * </p>
 */
public final class X509SecurityFloor {

    private static final String FINGERPRINT = "pki-floor-v1:no-sha1-signature-or-component";

    private X509SecurityFloor() {
    }

    /**
     * Returns immutable security-floor semantics for authority provenance.
     *
     * @return stable floor fingerprint
     */
    public static String semanticFingerprint() {
        return FINGERPRINT;
    }

    /**
     * Enforces the immutable security floor.
     *
     * @param identity requested exact identity
     * @throws IllegalArgumentException if the identity contains forbidden SHA-1
     *                                  semantics
     */
    public static void requirePermitted(AlgorithmIdentity identity) {
        Objects.requireNonNull(identity, "identity");
        String canonical = identity.canonicalForm().toLowerCase(Locale.ROOT);
        if (canonical.contains("sha1") || canonical.contains("sha-1")) {
            throw new IllegalArgumentException("SHA-1 is forbidden for PKI signatures");
        }
    }
}
