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#ifndef CSAA_CRYPTO_H
#define CSAA_CRYPTO_H
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
/* Various useful cryptographic functions; shared between TM and SP. */
/* we use SHA256 for h() */
typedef struct hash_t {
/* a hash of all zeros is given a special meaning */
unsigned char hash[32];
} hash_t;
struct iomt_node {
uint64_t idx, next_idx; /* idx cannot be zero */
hash_t val; /* all zero indicates placeholder */
};
struct iomt {
int mt_leafcount, mt_logleaves; /* mt_logleaves must equal 2^mt_leafcount */
/* Each level of the IOMT is stored sequentially from left to
* right, top to bottom, as follows:
*
* [0]: root
* [1]: root left child
* [2]: root right child
* [3]: left child of [1]
* [4]: right child of [1]
* [5]: left child of [2]
* [6]: right child of [2],
*
* and so on.
*/
hash_t *mt_nodes; /* this has 2 * mt_leafcount - 1 elements. Note
* that the bottom level consists of hashes of
* the leaf nodes. */
struct iomt_node *mt_leaves;
};
/* guaranteed to be zero */
static const struct hash_t hash_null = { { 0 } };
bool encloses(uint64_t b, uint64_t bprime, uint64_t a);
bool hash_equals(hash_t a, hash_t b);
bool is_zero(hash_t u);
hash_t hash_node(const struct iomt_node *node);
hash_t hash_xor(hash_t a, hash_t b);
hash_t sha256(const void *data, size_t datalen);
hash_t hmac_sha256(const void *data, size_t datalen, const void *key, size_t keylen);
hash_t merkle_compute(hash_t node, const hash_t *comp, const int *orders, size_t n);
hash_t merkle_parent(hash_t u, hash_t v, int order);
/* Calculate the indicies of the complementary nodes to a
* leaf. `leafidx' is 0 for the rightmost leaf node. This function
* will return an array with a length equal to the number of levels in
* the tree minus one (the root is not a complentary node). The 0th
* element of the returned array will be the index of the immediate
* sibling, while the 1st element will be the index of the
* complementary node one level above the leaf node, and so on. Note
* that logleaves = log2(nleaves). If `orders' is not NULL, the
* function will additionally allocate an array of `logleaves' *
* sizeof(int) with each element representing whether each
* complementary node is a left or right child. */
int *bintree_complement(int leafidx, int logleaves, int **orders);
int *bintree_complement_ordersonly(int leafidx, int logleaves);
/* Return an array of indices of tree nodes that are dependent on a
* given leaf node. Will be ordered from nearest relative to root. */
int *bintree_ancestors(int leafidx, int logleaves);
hash_t *merkle_complement(const struct iomt *tree, int leafidx, int **orders);
hash_t *lookup_nodes(const hash_t *nodes, const int *indices, int n);
void restore_nodes(hash_t *nodes, const int *indices, const hash_t *values, int n);
/* This function is prefixed merkle_ because it does not know about
* any IOMT-specific properties (though it is still passed an iomt
* struct) */
void merkle_update(struct iomt *tree, uint64_t leafidx, hash_t newval, hash_t **old_dep);
struct iomt *iomt_new(int logleaves);
struct iomt *iomt_dup(const struct iomt *tree);
void iomt_free(struct iomt *tree);
void iomt_update(struct iomt *tree, uint64_t idx, hash_t newval);
void iomt_update_by_leafidx(struct iomt *tree, uint64_t leafidx,
uint64_t new_idx, uint64_t new_next_idx, hash_t new_val);
void iomt_fill(struct iomt *tree);
void iomt_dump(const struct iomt *tree);
/* All linear searches... slow! */
struct iomt_node *iomt_find_leaf(const struct iomt *tree, uint64_t idx);
struct iomt_node *iomt_find_encloser(const struct iomt *tree, uint64_t idx);
struct iomt_node *iomt_find_leaf_or_encloser(const struct iomt *tree, uint64_t idx);
int bintree_parent(int idx);
int bintree_sibling(int idx);
uint64_t hash_to_u64(hash_t h);
hash_t u64_to_hash(uint64_t n);
void dump_hash(hash_t u);
struct hashstring {
char str[32 * 2 + 1];
};
struct hashstring hash_format(hash_t h, int n);
hash_t crypt_secret(hash_t encrypted_secret,
uint64_t file_idx, uint64_t file_counter,
const void *key, size_t keylen);
hash_t calc_lambda(hash_t gamma, const struct iomt *buildcode, const struct iomt *composefile, hash_t kf);
/* self-test */
void crypto_test(void);
#endif
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