/*
 * pkcs8_ed25519.h -- extract the raw 32-byte Ed25519 seed from a
 * PKCS#8 DER-encoded private key (RFC 8410 OneAsymmetricKey), for
 * mkcapsule's host-side capsule signing step (Milestone 6, Phase 8).
 *
 * Host-only: this never runs in the kernel (the kernel never signs, see
 * ed25519.h). Deliberately its own narrow, from-scratch DER walker, not
 * shared with src/starkernel/crypto/x509_ed25519.c -- that file walks a
 * full Certificate structure to a *public* key; this one walks the much
 * smaller PKCS#8 OneAsymmetricKey structure to a *private* key seed.
 * Small enough that duplicating the handful of TLV-walking lines is
 * simpler and easier to audit independently than threading a shared
 * header between the kernel crypto tree and host build tooling.
 */
#ifndef TOOLS_PKCS8_ED25519_H
#define TOOLS_PKCS8_ED25519_H

#include <stdint.h>
#include <stddef.h>

/* Returns 0 on success (seed_out[32] filled), -1 on any malformed
 * encoding or non-Ed25519 algorithm. Never faults on malformed input. */
int pkcs8_extract_ed25519_seed(const uint8_t *der, size_t der_len,
                                uint8_t seed_out[32]);

#endif /* TOOLS_PKCS8_ED25519_H */