/*
This file is part of GNUnet.
- (C) 2001-2013 Christian Grothoff (and other contributing authors)
+ Copyright (C) 2001-2013 GNUnet e.V.
- GNUnet is free software; you can redistribute it and/or modify
- it under the terms of the GNU General Public License as published
- by the Free Software Foundation; either version 3, or (at your
- option) any later version.
+ GNUnet is free software: you can redistribute it and/or modify it
+ under the terms of the GNU Affero General Public License as published
+ by the Free Software Foundation, either version 3 of the License,
+ or (at your option) any later version.
GNUnet is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- General Public License for more details.
+ Affero General Public License for more details.
- You should have received a copy of the GNU General Public License
- along with GNUnet; see the file COPYING. If not, write to the
- Free Software Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA.
+ You should have received a copy of the GNU Affero General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
-*/
+ SPDX-License-Identifier: AGPL3.0-or-later
+ */
/**
* @file util/crypto_hash.c
- * @brief SHA-512 GNUNET_CRYPTO_hash related functions
+ * @brief SHA-512 #GNUNET_CRYPTO_hash() related functions
* @author Christian Grothoff
*/
-
#include "platform.h"
-#include "gnunet_util_lib.h"
+#include "gnunet_crypto_lib.h"
+#include "gnunet_strings_lib.h"
+#include "benchmark.h"
#include <gcrypt.h>
-#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+#define LOG(kind, ...) GNUNET_log_from(kind, "util-crypto-hash", __VA_ARGS__)
-#define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file (kind, "util", syscall, filename)
+#define LOG_STRERROR_FILE(kind, syscall, filename) GNUNET_log_from_strerror_file(kind, "util-crypto-hash", syscall, filename)
/**
* Hash block of given size.
*
- * @param block the data to GNUNET_CRYPTO_hash, length is given as a second argument
- * @param size the length of the data to GNUNET_CRYPTO_hash
+ * @param block the data to #GNUNET_CRYPTO_hash, length is given as a second argument
+ * @param size the length of the data to #GNUNET_CRYPTO_hash in @a block
* @param ret pointer to where to write the hashcode
*/
void
-GNUNET_CRYPTO_hash (const void *block, size_t size, struct GNUNET_HashCode * ret)
+GNUNET_CRYPTO_hash(const void *block,
+ size_t size,
+ struct GNUNET_HashCode *ret)
{
- gcry_md_hash_buffer (GCRY_MD_SHA512, ret, block, size);
-}
-
-
-/**
- * Context used when hashing a file.
- */
-struct GNUNET_CRYPTO_FileHashContext
-{
-
- /**
- * Function to call upon completion.
- */
- GNUNET_CRYPTO_HashCompletedCallback callback;
-
- /**
- * Closure for callback.
- */
- void *callback_cls;
-
- /**
- * IO buffer.
- */
- unsigned char *buffer;
-
- /**
- * Name of the file we are hashing.
- */
- char *filename;
-
- /**
- * File descriptor.
- */
- struct GNUNET_DISK_FileHandle *fh;
-
- /**
- * Cummulated hash.
- */
- gcry_md_hd_t md;
-
- /**
- * Size of the file.
- */
- uint64_t fsize;
-
- /**
- * Current offset.
- */
- uint64_t offset;
-
- /**
- * Current task for hashing.
- */
- GNUNET_SCHEDULER_TaskIdentifier task;
-
- /**
- * Priority we use.
- */
- enum GNUNET_SCHEDULER_Priority priority;
-
- /**
- * Blocksize.
- */
- size_t bsize;
-
-};
-
-
-/**
- * Report result of hash computation to callback
- * and free associated resources.
- */
-static void
-file_hash_finish (struct GNUNET_CRYPTO_FileHashContext *fhc,
- const struct GNUNET_HashCode * res)
-{
- fhc->callback (fhc->callback_cls, res);
- GNUNET_free (fhc->filename);
- if (!GNUNET_DISK_handle_invalid (fhc->fh))
- GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fhc->fh));
- gcry_md_close (fhc->md);
- GNUNET_free (fhc); /* also frees fhc->buffer */
-}
-
-
-/**
- * File hashing task.
- *
- * @param cls closure
- * @param tc context
- */
-static void
-file_hash_task (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
-{
- struct GNUNET_CRYPTO_FileHashContext *fhc = cls;
- struct GNUNET_HashCode *res;
- size_t delta;
-
- fhc->task = GNUNET_SCHEDULER_NO_TASK;
- GNUNET_assert (fhc->offset <= fhc->fsize);
- delta = fhc->bsize;
- if (fhc->fsize - fhc->offset < delta)
- delta = fhc->fsize - fhc->offset;
- if (delta != GNUNET_DISK_file_read (fhc->fh, fhc->buffer, delta))
- {
- LOG_STRERROR_FILE (GNUNET_ERROR_TYPE_WARNING, "read", fhc->filename);
- file_hash_finish (fhc, NULL);
- return;
- }
- gcry_md_write (fhc->md, fhc->buffer, delta);
- fhc->offset += delta;
- if (fhc->offset == fhc->fsize)
- {
- res = (struct GNUNET_HashCode *) gcry_md_read (fhc->md, GCRY_MD_SHA512);
- file_hash_finish (fhc, res);
- return;
- }
- fhc->task = GNUNET_SCHEDULER_add_with_priority (fhc->priority,
- &file_hash_task, fhc);
-}
-
-
-/**
- * Compute the hash of an entire file.
- *
- * @param priority scheduling priority to use
- * @param filename name of file to hash
- * @param blocksize number of bytes to process in one task
- * @param callback function to call upon completion
- * @param callback_cls closure for callback
- * @return NULL on (immediate) errror
- */
-struct GNUNET_CRYPTO_FileHashContext *
-GNUNET_CRYPTO_hash_file (enum GNUNET_SCHEDULER_Priority priority,
- const char *filename, size_t blocksize,
- GNUNET_CRYPTO_HashCompletedCallback callback,
- void *callback_cls)
-{
- struct GNUNET_CRYPTO_FileHashContext *fhc;
-
- GNUNET_assert (blocksize > 0);
- fhc =
- GNUNET_malloc (sizeof (struct GNUNET_CRYPTO_FileHashContext) + blocksize);
- fhc->callback = callback;
- fhc->callback_cls = callback_cls;
- fhc->buffer = (unsigned char *) &fhc[1];
- fhc->filename = GNUNET_strdup (filename);
- if (GPG_ERR_NO_ERROR != gcry_md_open (&fhc->md, GCRY_MD_SHA512, 0))
- {
- GNUNET_break (0);
- GNUNET_free (fhc);
- return NULL;
- }
- fhc->bsize = blocksize;
- if (GNUNET_OK != GNUNET_DISK_file_size (filename, &fhc->fsize, GNUNET_NO, GNUNET_YES))
- {
- GNUNET_free (fhc->filename);
- GNUNET_free (fhc);
- return NULL;
- }
- fhc->fh =
- GNUNET_DISK_file_open (filename, GNUNET_DISK_OPEN_READ,
- GNUNET_DISK_PERM_NONE);
- if (!fhc->fh)
- {
- GNUNET_free (fhc->filename);
- GNUNET_free (fhc);
- return NULL;
- }
- fhc->priority = priority;
- fhc->task =
- GNUNET_SCHEDULER_add_with_priority (priority, &file_hash_task, fhc);
- return fhc;
-}
-
-
-/**
- * Cancel a file hashing operation.
- *
- * @param fhc operation to cancel (callback must not yet have been invoked)
- */
-void
-GNUNET_CRYPTO_hash_file_cancel (struct GNUNET_CRYPTO_FileHashContext *fhc)
-{
- GNUNET_SCHEDULER_cancel (fhc->task);
- GNUNET_free (fhc->filename);
- GNUNET_break (GNUNET_OK == GNUNET_DISK_file_close (fhc->fh));
- GNUNET_free (fhc);
+ BENCHMARK_START(hash);
+ gcry_md_hash_buffer(GCRY_MD_SHA512, ret, block, size);
+ BENCHMARK_END(hash);
}
* safely cast to char*, a '\\0' termination is set).
*/
void
-GNUNET_CRYPTO_hash_to_enc (const struct GNUNET_HashCode *block,
- struct GNUNET_CRYPTO_HashAsciiEncoded *result)
+GNUNET_CRYPTO_hash_to_enc(const struct GNUNET_HashCode *block,
+ struct GNUNET_CRYPTO_HashAsciiEncoded *result)
{
char *np;
- np = GNUNET_STRINGS_data_to_string ((const unsigned char *) block,
- sizeof (struct GNUNET_HashCode),
- (char*) result,
- sizeof (struct GNUNET_CRYPTO_HashAsciiEncoded) - 1);
- GNUNET_assert (NULL != np);
+ np = GNUNET_STRINGS_data_to_string((const unsigned char *)block,
+ sizeof(struct GNUNET_HashCode),
+ (char *)result,
+ sizeof(struct GNUNET_CRYPTO_HashAsciiEncoded) - 1);
+ GNUNET_assert(NULL != np);
*np = '\0';
}
* @return #GNUNET_OK on success, #GNUNET_SYSERR if result has the wrong encoding
*/
int
-GNUNET_CRYPTO_hash_from_string2 (const char *enc,
- size_t enclen,
- struct GNUNET_HashCode *result)
+GNUNET_CRYPTO_hash_from_string2(const char *enc,
+ size_t enclen,
+ struct GNUNET_HashCode *result)
{
char upper_enc[enclen];
char *up_ptr = upper_enc;
- GNUNET_STRINGS_utf8_toupper (enc, up_ptr);
+ GNUNET_STRINGS_utf8_toupper(enc, up_ptr);
- return GNUNET_STRINGS_string_to_data (upper_enc, enclen,
- (unsigned char*) result,
- sizeof (struct GNUNET_HashCode));
+ return GNUNET_STRINGS_string_to_data(upper_enc, enclen,
+ (unsigned char*)result,
+ sizeof(struct GNUNET_HashCode));
}
* hashcode proximity.
*/
unsigned int
-GNUNET_CRYPTO_hash_distance_u32 (const struct GNUNET_HashCode *a,
- const struct GNUNET_HashCode *b)
+GNUNET_CRYPTO_hash_distance_u32(const struct GNUNET_HashCode *a,
+ const struct GNUNET_HashCode *b)
{
unsigned int x1 = (a->bits[1] - b->bits[1]) >> 16;
unsigned int x2 = (b->bits[1] - a->bits[1]) >> 16;
- return (x1 * x2);
+ return(x1 * x2);
}
* @param result hash code that is randomized
*/
void
-GNUNET_CRYPTO_hash_create_random (enum GNUNET_CRYPTO_Quality mode,
- struct GNUNET_HashCode *result)
+GNUNET_CRYPTO_hash_create_random(enum GNUNET_CRYPTO_Quality mode,
+ struct GNUNET_HashCode *result)
{
int i;
- for (i = (sizeof (struct GNUNET_HashCode) / sizeof (uint32_t)) - 1; i >= 0; i--)
- result->bits[i] = GNUNET_CRYPTO_random_u32 (mode, UINT32_MAX);
+ for (i = (sizeof(struct GNUNET_HashCode) / sizeof(uint32_t)) - 1; i >= 0; i--)
+ result->bits[i] = GNUNET_CRYPTO_random_u32(mode, UINT32_MAX);
}
* @param result set to b - a
*/
void
-GNUNET_CRYPTO_hash_difference (const struct GNUNET_HashCode *a,
- const struct GNUNET_HashCode *b,
- struct GNUNET_HashCode *result)
+GNUNET_CRYPTO_hash_difference(const struct GNUNET_HashCode *a,
+ const struct GNUNET_HashCode *b,
+ struct GNUNET_HashCode *result)
{
int i;
- for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
+ for (i = (sizeof(struct GNUNET_HashCode) / sizeof(unsigned int)) - 1; i >= 0; i--)
result->bits[i] = b->bits[i] - a->bits[i];
}
* @param result set to a + delta
*/
void
-GNUNET_CRYPTO_hash_sum (const struct GNUNET_HashCode * a,
- const struct GNUNET_HashCode * delta, struct GNUNET_HashCode * result)
+GNUNET_CRYPTO_hash_sum(const struct GNUNET_HashCode * a,
+ const struct GNUNET_HashCode * delta, struct GNUNET_HashCode * result)
{
int i;
- for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
+ for (i = (sizeof(struct GNUNET_HashCode) / sizeof(unsigned int)) - 1; i >= 0; i--)
result->bits[i] = delta->bits[i] + a->bits[i];
}
* @param result set to a ^ b
*/
void
-GNUNET_CRYPTO_hash_xor (const struct GNUNET_HashCode * a, const struct GNUNET_HashCode * b,
- struct GNUNET_HashCode * result)
+GNUNET_CRYPTO_hash_xor(const struct GNUNET_HashCode *a,
+ const struct GNUNET_HashCode *b,
+ struct GNUNET_HashCode *result)
{
int i;
- for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
+ for (i = (sizeof(struct GNUNET_HashCode) / sizeof(unsigned int)) - 1; i >= 0; i--)
result->bits[i] = a->bits[i] ^ b->bits[i];
}
* @param iv set to a valid initialization vector
*/
void
-GNUNET_CRYPTO_hash_to_aes_key (const struct GNUNET_HashCode *hc,
- struct GNUNET_CRYPTO_SymmetricSessionKey *skey,
- struct GNUNET_CRYPTO_SymmetricInitializationVector *iv)
+GNUNET_CRYPTO_hash_to_aes_key(const struct GNUNET_HashCode *hc,
+ struct GNUNET_CRYPTO_SymmetricSessionKey *skey,
+ struct GNUNET_CRYPTO_SymmetricInitializationVector *iv)
{
- GNUNET_assert (GNUNET_YES ==
- GNUNET_CRYPTO_kdf (skey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
- "Hash key derivation", strlen ("Hash key derivation"),
- hc, sizeof (struct GNUNET_HashCode),
- NULL, 0));
- GNUNET_assert (GNUNET_YES ==
- GNUNET_CRYPTO_kdf (iv, sizeof (struct GNUNET_CRYPTO_SymmetricInitializationVector),
- "Initialization vector derivation", strlen ("Initialization vector derivation"),
- hc, sizeof (struct GNUNET_HashCode),
- NULL, 0));
+ GNUNET_assert(GNUNET_YES ==
+ GNUNET_CRYPTO_kdf(skey, sizeof(struct GNUNET_CRYPTO_SymmetricSessionKey),
+ "Hash key derivation", strlen("Hash key derivation"),
+ hc, sizeof(struct GNUNET_HashCode),
+ NULL, 0));
+ GNUNET_assert(GNUNET_YES ==
+ GNUNET_CRYPTO_kdf(iv, sizeof(struct GNUNET_CRYPTO_SymmetricInitializationVector),
+ "Initialization vector derivation", strlen("Initialization vector derivation"),
+ hc, sizeof(struct GNUNET_HashCode),
+ NULL, 0));
}
* @return Bit \a bit from hashcode \a code, -1 for invalid index
*/
int
-GNUNET_CRYPTO_hash_get_bit (const struct GNUNET_HashCode * code, unsigned int bit)
+GNUNET_CRYPTO_hash_get_bit(const struct GNUNET_HashCode * code, unsigned int bit)
{
- GNUNET_assert (bit < 8 * sizeof (struct GNUNET_HashCode));
- return (((unsigned char *) code)[bit >> 3] & (1 << (bit & 7))) > 0;
+ GNUNET_assert(bit < 8 * sizeof(struct GNUNET_HashCode));
+ return (((unsigned char *)code)[bit >> 3] & (1 << (bit & 7))) > 0;
}
* @return the number of bits that match
*/
unsigned int
-GNUNET_CRYPTO_hash_matching_bits (const struct GNUNET_HashCode * first,
- const struct GNUNET_HashCode * second)
+GNUNET_CRYPTO_hash_matching_bits(const struct GNUNET_HashCode * first,
+ const struct GNUNET_HashCode * second)
{
unsigned int i;
- for (i = 0; i < sizeof (struct GNUNET_HashCode) * 8; i++)
- if (GNUNET_CRYPTO_hash_get_bit (first, i) !=
- GNUNET_CRYPTO_hash_get_bit (second, i))
+ for (i = 0; i < sizeof(struct GNUNET_HashCode) * 8; i++)
+ if (GNUNET_CRYPTO_hash_get_bit(first, i) !=
+ GNUNET_CRYPTO_hash_get_bit(second, i))
return i;
- return sizeof (struct GNUNET_HashCode) * 8;
+ return sizeof(struct GNUNET_HashCode) * 8;
}
* @return 1 if h1 > h2, -1 if h1 < h2 and 0 if h1 == h2.
*/
int
-GNUNET_CRYPTO_hash_cmp (const struct GNUNET_HashCode *h1,
- const struct GNUNET_HashCode *h2)
+GNUNET_CRYPTO_hash_cmp(const struct GNUNET_HashCode *h1,
+ const struct GNUNET_HashCode *h2)
{
unsigned int *i1;
unsigned int *i2;
int i;
- i1 = (unsigned int *) h1;
- i2 = (unsigned int *) h2;
- for (i = (sizeof (struct GNUNET_HashCode) / sizeof (unsigned int)) - 1; i >= 0; i--)
- {
- if (i1[i] > i2[i])
- return 1;
- if (i1[i] < i2[i])
- return -1;
- }
+ i1 = (unsigned int *)h1;
+ i2 = (unsigned int *)h2;
+ for (i = (sizeof(struct GNUNET_HashCode) / sizeof(unsigned int)) - 1; i >= 0; i--)
+ {
+ if (i1[i] > i2[i])
+ return 1;
+ if (i1[i] < i2[i])
+ return -1;
+ }
return 0;
}
* @return -1 if h1 is closer, 1 if h2 is closer and 0 if h1==h2.
*/
int
-GNUNET_CRYPTO_hash_xorcmp (const struct GNUNET_HashCode *h1,
- const struct GNUNET_HashCode *h2,
- const struct GNUNET_HashCode *target)
+GNUNET_CRYPTO_hash_xorcmp(const struct GNUNET_HashCode *h1,
+ const struct GNUNET_HashCode *h2,
+ const struct GNUNET_HashCode *target)
{
int i;
unsigned int d1;
unsigned int d2;
- for (i = sizeof (struct GNUNET_HashCode) / sizeof (unsigned int) - 1; i >= 0; i--)
- {
- d1 = ((unsigned int *) h1)[i] ^ ((unsigned int *) target)[i];
- d2 = ((unsigned int *) h2)[i] ^ ((unsigned int *) target)[i];
- if (d1 > d2)
- return 1;
- else if (d1 < d2)
- return -1;
- }
+ for (i = sizeof(struct GNUNET_HashCode) / sizeof(unsigned int) - 1; i >= 0; i--)
+ {
+ d1 = ((unsigned int *)h1)[i] ^ ((unsigned int *)target)[i];
+ d2 = ((unsigned int *)h2)[i] ^ ((unsigned int *)target)[i];
+ if (d1 > d2)
+ return 1;
+ else if (d1 < d2)
+ return -1;
+ }
return 0;
}
* @param ... pair of void * & size_t for context chunks, terminated by NULL
*/
void
-GNUNET_CRYPTO_hmac_derive_key (struct GNUNET_CRYPTO_AuthKey *key,
- const struct GNUNET_CRYPTO_SymmetricSessionKey *rkey,
- const void *salt, size_t salt_len, ...)
+GNUNET_CRYPTO_hmac_derive_key(struct GNUNET_CRYPTO_AuthKey *key,
+ const struct GNUNET_CRYPTO_SymmetricSessionKey *rkey,
+ const void *salt, size_t salt_len, ...)
{
va_list argp;
- va_start (argp, salt_len);
- GNUNET_CRYPTO_hmac_derive_key_v (key, rkey, salt, salt_len, argp);
- va_end (argp);
+ va_start(argp, salt_len);
+ GNUNET_CRYPTO_hmac_derive_key_v(key, rkey, salt, salt_len, argp);
+ va_end(argp);
}
* @param argp pair of void * & size_t for context chunks, terminated by NULL
*/
void
-GNUNET_CRYPTO_hmac_derive_key_v (struct GNUNET_CRYPTO_AuthKey *key,
- const struct GNUNET_CRYPTO_SymmetricSessionKey *rkey,
- const void *salt, size_t salt_len,
- va_list argp)
+GNUNET_CRYPTO_hmac_derive_key_v(struct GNUNET_CRYPTO_AuthKey *key,
+ const struct GNUNET_CRYPTO_SymmetricSessionKey *rkey,
+ const void *salt, size_t salt_len,
+ va_list argp)
{
- GNUNET_CRYPTO_kdf_v (key->key, sizeof (key->key),
- salt, salt_len,
- rkey, sizeof (struct GNUNET_CRYPTO_SymmetricSessionKey),
- argp);
+ GNUNET_CRYPTO_kdf_v(key->key, sizeof(key->key),
+ salt, salt_len,
+ rkey, sizeof(struct GNUNET_CRYPTO_SymmetricSessionKey),
+ argp);
}
/**
* Calculate HMAC of a message (RFC 2104)
+ * TODO: Shouldn' this be the standard hmac function and
+ * the above be renamed?
*
* @param key secret key
+ * @param key_len secret key length
* @param plaintext input plaintext
* @param plaintext_len length of @a plaintext
* @param hmac where to store the hmac
*/
void
-GNUNET_CRYPTO_hmac (const struct GNUNET_CRYPTO_AuthKey *key,
- const void *plaintext, size_t plaintext_len,
- struct GNUNET_HashCode *hmac)
+GNUNET_CRYPTO_hmac_raw(const void *key, size_t key_len,
+ const void *plaintext, size_t plaintext_len,
+ struct GNUNET_HashCode *hmac)
{
static int once;
static gcry_md_hd_t md;
const unsigned char *mc;
- if (! once)
- {
- once = 1;
- GNUNET_assert (GPG_ERR_NO_ERROR ==
- gcry_md_open (&md, GCRY_MD_SHA512, GCRY_MD_FLAG_HMAC));
- }
+ if (!once)
+ {
+ once = 1;
+ GNUNET_assert(GPG_ERR_NO_ERROR ==
+ gcry_md_open(&md, GCRY_MD_SHA512, GCRY_MD_FLAG_HMAC));
+ }
else
- {
- gcry_md_reset (md);
- }
- gcry_md_setkey (md, key->key, sizeof (key->key));
- gcry_md_write (md, plaintext, plaintext_len);
- mc = gcry_md_read (md, GCRY_MD_SHA512);
- GNUNET_assert (NULL != mc);
- memcpy (hmac->bits, mc, sizeof (hmac->bits));
+ {
+ gcry_md_reset(md);
+ }
+ gcry_md_setkey(md, key, key_len);
+ gcry_md_write(md, plaintext, plaintext_len);
+ mc = gcry_md_read(md, GCRY_MD_SHA512);
+ GNUNET_assert(NULL != mc);
+ GNUNET_memcpy(hmac->bits, mc, sizeof(hmac->bits));
+}
+
+
+/**
+ * Calculate HMAC of a message (RFC 2104)
+ *
+ * @param key secret key
+ * @param plaintext input plaintext
+ * @param plaintext_len length of @a plaintext
+ * @param hmac where to store the hmac
+ */
+void
+GNUNET_CRYPTO_hmac(const struct GNUNET_CRYPTO_AuthKey *key,
+ const void *plaintext, size_t plaintext_len,
+ struct GNUNET_HashCode *hmac)
+{
+ GNUNET_CRYPTO_hmac_raw((void*)key->key, sizeof(key->key),
+ plaintext, plaintext_len,
+ hmac);
+}
+
+
+/**
+ * Context for cummulative hashing.
+ */
+struct GNUNET_HashContext {
+ /**
+ * Internal state of the hash function.
+ */
+ gcry_md_hd_t hd;
+};
+
+
+/**
+ * Start incremental hashing operation.
+ *
+ * @return context for incremental hash computation
+ */
+struct GNUNET_HashContext *
+GNUNET_CRYPTO_hash_context_start()
+{
+ struct GNUNET_HashContext *hc;
+
+ BENCHMARK_START(hash_context_start);
+
+ hc = GNUNET_new(struct GNUNET_HashContext);
+ GNUNET_assert(0 ==
+ gcry_md_open(&hc->hd,
+ GCRY_MD_SHA512,
+ 0));
+
+ BENCHMARK_END(hash_context_start);
+
+ return hc;
+}
+
+
+/**
+ * Add data to be hashed.
+ *
+ * @param hc cummulative hash context
+ * @param buf data to add
+ * @param size number of bytes in @a buf
+ */
+void
+GNUNET_CRYPTO_hash_context_read(struct GNUNET_HashContext *hc,
+ const void *buf,
+ size_t size)
+{
+ BENCHMARK_START(hash_context_read);
+ gcry_md_write(hc->hd, buf, size);
+ BENCHMARK_END(hash_context_read);
+}
+
+
+/**
+ * Finish the hash computation.
+ *
+ * @param hc hash context to use
+ * @param r_hash where to write the latest / final hash code
+ */
+void
+GNUNET_CRYPTO_hash_context_finish(struct GNUNET_HashContext *hc,
+ struct GNUNET_HashCode *r_hash)
+{
+ const void *res = gcry_md_read(hc->hd, 0);
+
+ BENCHMARK_START(hash_context_finish);
+
+ GNUNET_assert(NULL != res);
+ if (NULL != r_hash)
+ GNUNET_memcpy(r_hash,
+ res,
+ sizeof(struct GNUNET_HashCode));
+ GNUNET_CRYPTO_hash_context_abort(hc);
+ BENCHMARK_END(hash_context_finish);
+}
+
+
+/**
+ * Abort hashing, do not bother calculating final result.
+ *
+ * @param hc hash context to destroy
+ */
+void
+GNUNET_CRYPTO_hash_context_abort(struct GNUNET_HashContext *hc)
+{
+ gcry_md_close(hc->hd);
+ GNUNET_free(hc);
}