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2166d7e | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 | #ifndef L8_WORM_H
#define L8_WORM_H
/* Layer 8 - WORM ledger: an append-only hash chain of seals.
*
* seal_0 = SHA-256("cstack-worm-genesis-v1")
* seal_i = SHA-256("cstack-worm-seal-v1" || be64(i) || seal_{i-1} || witness_digest_i)
*
* There is no API to modify or remove an entry. A file-backed ledger is opened O_APPEND, one line
* per seal ("index witness_hex seal_hex"), and is fully re-verified when opened: any edit,
* deletion, reordering or truncated line is reported as CS_ERR_TAMPER. */
#include <stddef.h>
#include <stdint.h>
#include "cs_status.h"
typedef struct worm_seal {
uint64_t index;
uint8_t witness_digest[32]; /* all zero for seal_0 */
uint8_t seal[32];
} worm_seal;
typedef struct worm_ledger {
worm_seal *seals;
size_t count, cap;
int fd; /* -1 when memory only */
} worm_ledger;
/* path NULL = memory only. An existing file is loaded and verified; a new one gets seal_0. */
cs_status worm_open(worm_ledger *l, const char *path);
cs_status worm_append(worm_ledger *l, const uint8_t witness_digest[32], worm_seal *out);
void worm_close(worm_ledger *l);
/* Pointers returned by worm_at / worm_head are valid only until the next worm_append. */
size_t worm_count(const worm_ledger *l);
const worm_seal *worm_at(const worm_ledger *l, size_t i);
const worm_seal *worm_head(const worm_ledger *l);
/* Re-derives the whole chain; CS_ERR_TAMPER on any inconsistency. */
cs_status worm_verify(const worm_ledger *l);
cs_status worm_verify_chain(const worm_seal *seals, size_t n);
#endif
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