wifi-tally_Oostendam/nodemcu-firmware/app/crypto/digests.h
Eljakim Herrewijnen 50b5fc1824 Initial commit
2021-09-27 21:52:27 +02:00

126 lines
4.9 KiB
C

#ifndef _CRYPTO_DIGESTS_H_
#define _CRYPTO_DIGESTS_H_
#include <stdint.h>
#include <stddef.h>
typedef void (*create_ctx_fn)(void *ctx);
typedef void (*update_ctx_fn)(void *ctx, const uint8_t *msg, int len);
typedef void (*finalize_ctx_fn)(uint8_t *digest, void *ctx);
typedef int32_t ( *read_fn )(int fd, void *ptr, size_t len);
/**
* Description of a message digest mechanism.
*
* Typical usage (if not using the crypto_xxxx() functions below):
* digest_mech_info_t *mi = crypto_digest_mech (chosen_algorithm);
* void *ctx = os_malloc (mi->ctx_size);
* mi->create (ctx);
* mi->update (ctx, data, len);
* ...
* uint8_t *digest = os_malloc (mi->digest_size);
* mi->finalize (digest, ctx);
* ...
* os_free (ctx);
* os_free (digest);
*/
typedef struct
{
/* Note: All entries are 32bit to enable placement using ICACHE_RODATA_ATTR.*/
const char * name;
create_ctx_fn create;
update_ctx_fn update;
finalize_ctx_fn finalize;
uint32_t ctx_size;
uint32_t digest_size;
uint32_t block_size;
} digest_mech_info_t;
/**
* Looks up the mech data for a specified digest algorithm.
* @param mech The name of the algorithm, e.g. "MD5", "SHA256"
* @returns The mech data, or null if the mech is unknown.
*/
const digest_mech_info_t *crypto_digest_mech (const char *mech);
/**
* Wrapper function for performing a one-in-all hashing operation.
* @param mi A mech from @c crypto_digest_mech(). A null pointer @c mi
* is harmless, but will of course result in an error return.
* @param data The data to create a digest for.
* @param data_len Number of bytes at @c data to digest.
* @param digest Output buffer, must be at least @c mi->digest_size in size.
* @return 0 on success, non-zero on error.
*/
int crypto_hash (const digest_mech_info_t *mi, const char *data, size_t data_len, uint8_t *digest);
/**
* Wrapper function for performing a one-in-all hashing operation of a file.
* @param mi A mech from @c crypto_digest_mech(). A null pointer @c mi
* is harmless, but will of course result in an error return.
* @param read Pointer to the read function (e.g. fs_read)
* @param readarg Argument to pass to the read function (e.g. file descriptor)
* @param digest Output buffer, must be at least @c mi->digest_size in size.
* @return 0 on success, non-zero on error.
*/
int crypto_fhash (const digest_mech_info_t *mi, read_fn read, int readarg, uint8_t *digest);
/**
* Commence calculating a HMAC signature.
*
* Once this fuction returns successfully, the @c ctx may be updated with
* data in multiple passes uses @c mi->update(), before being finalized via
* @c crypto_hmac_finalize().
*
* @param ctx A created context for the given mech @c mi.
* @param mi A mech from @c crypto_digest_mech().
* @param key The key bytes to use.
* @param key_len Number of bytes the @c key comprises.
* @param k_opad Buffer of size @c mi->block_size bytes to store the second
* round of key material in.
* Must be passed to @c crypto_hmac_finalize().
*/
void crypto_hmac_begin (void *ctx, const digest_mech_info_t *mi, const char *key, size_t key_len, uint8_t *k_opad);
/**
* Finalizes calculating a HMAC signature.
* @param ctx The created context used with @c crypto_hmac_begin().
* @param mi The mech used with @c crypto_hmac_begin().
* @param k_opad Second round of keying material, obtained
* from @c crypto_hmac_begin().
* @param digest Output buffer, must be at least @c mi->digest_size in size.
*/
void crypto_hmac_finalize (void *ctx, const digest_mech_info_t *mi, const uint8_t *k_opad, uint8_t *digest);
/**
* Generate a HMAC signature in one pass.
* Implemented in terms of @c crypto_hmac_begin() / @c crypto_hmac_end().
* @param mi A mech from @c crypto_digest_mech(). A null pointer @c mi
* is harmless, but will of course result in an error return.
* @param data The data to generate a signature for.
* @param data_len Number of bytes at @c data to process.
* @param key The key to use.
* @param key_len Number of bytes the @c key comprises.
* @param digest Output buffer, must be at least @c mi->digest_size in size.
* @return 0 on success, non-zero on error.
*/
int crypto_hmac (const digest_mech_info_t *mi, const char *data, size_t data_len, const char *key, size_t key_len, uint8_t *digest);
/**
* Perform ASCII Hex encoding. Does not null-terminate the buffer.
*
* @param bin The buffer to ascii-hex encode.
* @param bin_len Number of bytes in @c bin to encode.
* @param outbuf Output buffer, must be at least @c bin_len*2 bytes in size.
* Note that in-place encoding is supported, and as such
* bin==outbuf is safe, provided the buffer is large enough.
*/
void crypto_encode_asciihex (const char *bin, size_t bin_len, char *outbuf);
/** Text string "0123456789abcdef" */
const char crypto_hexbytes[17];
#endif