gnsrecord_pow.c File Reference

#include "platform.h"
#include "gnunet_common.h"
#include "gnunet_util_lib.h"
#include "gnunet_gnsrecord_lib.h"
#include "gnunet_signatures.h"
#include <inttypes.h>
#include "gnsrecord_crypto.h"

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Data Structures
struct	BestPow
	API for proof of work. More...
struct	GNUNET_GNSRECORD_PowCalculationHandle
	The handle to a PoW calculation. More...

Functions
static unsigned int	calculate_score (const struct GNUNET_GNSRECORD_PowCalculationHandle *ph)
	Calculate the average zeros in the pows.
struct GNUNET_GNSRECORD_SignaturePurposePS *	GNR_create_signature_message (const struct GNUNET_GNSRECORD_PowP *pow)
	Create the revocation metadata to sign for a revocation message.
static enum GNUNET_GenericReturnValue	check_signature_identity (const struct GNUNET_GNSRECORD_PowP *pow, const struct GNUNET_CRYPTO_BlindablePublicKey *key)
static enum GNUNET_GenericReturnValue	check_signature (const struct GNUNET_GNSRECORD_PowP *pow)
enum GNUNET_GenericReturnValue	GNUNET_GNSRECORD_check_pow (const struct GNUNET_GNSRECORD_PowP *pow, unsigned int difficulty, struct GNUNET_TIME_Relative epoch_duration)
	Check if the given proof-of-work is valid.
static enum GNUNET_GenericReturnValue	sign_pow_identity (const struct GNUNET_CRYPTO_BlindablePrivateKey *key, struct GNUNET_GNSRECORD_PowP *pow)
static enum GNUNET_GenericReturnValue	sign_pow (const struct GNUNET_CRYPTO_BlindablePrivateKey *key, struct GNUNET_GNSRECORD_PowP *pow)
void	GNUNET_GNSRECORD_pow_init (const struct GNUNET_CRYPTO_BlindablePrivateKey *key, struct GNUNET_GNSRECORD_PowP *pow)
	Initializes a fresh PoW computation.
struct GNUNET_GNSRECORD_PowCalculationHandle *	GNUNET_GNSRECORD_pow_start (struct GNUNET_GNSRECORD_PowP *pow, int epochs, unsigned int difficulty)
	Starts a proof-of-work calculation given the pow object as well as target epochs and difficulty.
static int	cmp_pow_value (const void *a, const void *b)
	Comparison function for quicksort.
enum GNUNET_GenericReturnValue	GNUNET_GNSRECORD_pow_round (struct GNUNET_GNSRECORD_PowCalculationHandle *pc)
	Calculate a key revocation valid for broadcasting for a number of epochs.
size_t	GNUNET_GNSRECORD_proof_get_size (const struct GNUNET_GNSRECORD_PowP *pow)
void	GNUNET_GNSRECORD_pow_stop (struct GNUNET_GNSRECORD_PowCalculationHandle *pc)
	Stop a PoW calculation.

Variables
static struct GNUNET_CRYPTO_PowSalt	salt = { "GnsRevocationPow" }

Function Documentation

calculate_score()

static unsigned int calculate_score ( const struct GNUNET_GNSRECORD_PowCalculationHandle *  ph )

static

Calculate the average zeros in the pows.

Parameters

ph	the PowHandle

Returns

the average number of zeros.

Definition at line 93 of file gnsrecord_pow.c.

{
  double sum = 0.0;
  for (unsigned int j = 0; j<POW_COUNT; j++)
    sum += ph->best[j].bits;
  return sum / POW_COUNT;
}

References GNUNET_GNSRECORD_PowCalculationHandle::best, BestPow::bits, and POW_COUNT.

Referenced by GNUNET_GNSRECORD_pow_round().

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GNR_create_signature_message()

struct GNUNET_GNSRECORD_SignaturePurposePS * GNR_create_signature_message

(

const struct GNUNET_GNSRECORD_PowP *

pow

)

Create the revocation metadata to sign for a revocation message.

Parameters

pow	the PoW to sign

Returns

the signature purpose

Definition at line 103 of file gnsrecord_pow.c.

{
  struct GNUNET_GNSRECORD_SignaturePurposePS *spurp;
  const struct GNUNET_CRYPTO_BlindablePublicKey *pk;
  size_t ksize;
 
  pk = (const struct GNUNET_CRYPTO_BlindablePublicKey *) &pow[1];
  ksize = GNUNET_CRYPTO_public_key_get_length (pk);
  spurp = GNUNET_malloc (sizeof (*spurp) + ksize);
  spurp->timestamp = pow->timestamp;
  spurp->purpose.purpose = htonl (GNUNET_SIGNATURE_PURPOSE_GNS_REVOCATION);
  spurp->purpose.size = htonl (sizeof(*spurp) + ksize);
  GNUNET_CRYPTO_write_blindable_pk_to_buffer (pk,
                                              (char*) &spurp[1],
                                              ksize);
  return spurp;
}

References GNUNET_CRYPTO_public_key_get_length(), GNUNET_CRYPTO_write_blindable_pk_to_buffer(), GNUNET_malloc, GNUNET_SIGNATURE_PURPOSE_GNS_REVOCATION, pk, GNUNET_CRYPTO_SignaturePurpose::purpose, GNUNET_GNSRECORD_SignaturePurposePS::purpose, GNUNET_CRYPTO_SignaturePurpose::size, GNUNET_GNSRECORD_PowP::timestamp, and GNUNET_GNSRECORD_SignaturePurposePS::timestamp.

Referenced by check_signature_identity(), run_with_key(), and sign_pow_identity().

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check_signature_identity()

static enum GNUNET_GenericReturnValue check_signature_identity ( const struct GNUNET_GNSRECORD_PowP *  pow, const struct GNUNET_CRYPTO_BlindablePublicKey *  key  )

static

Definition at line 123 of file gnsrecord_pow.c.

{
  struct GNUNET_GNSRECORD_SignaturePurposePS *spurp;
  unsigned char *sig;
  size_t ksize;
  int ret;
 
  ksize = GNUNET_CRYPTO_public_key_get_length (key);
  spurp = GNR_create_signature_message (pow);
  sig = ((unsigned char*) &pow[1] + ksize);
  ret =
    GNUNET_CRYPTO_blinded_key_signature_verify_raw_ (
      GNUNET_SIGNATURE_PURPOSE_GNS_REVOCATION,
      &spurp->purpose,
      sig,
      key);
  GNUNET_free (spurp);
  return ret == GNUNET_OK ? GNUNET_OK : GNUNET_SYSERR;
}

References GNR_create_signature_message(), GNUNET_CRYPTO_blinded_key_signature_verify_raw_(), GNUNET_CRYPTO_public_key_get_length(), GNUNET_free, GNUNET_OK, GNUNET_SIGNATURE_PURPOSE_GNS_REVOCATION, GNUNET_SYSERR, key, GNUNET_GNSRECORD_SignaturePurposePS::purpose, and ret.

Referenced by check_signature().

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check_signature()

static enum GNUNET_GenericReturnValue check_signature ( const struct GNUNET_GNSRECORD_PowP *  pow )

static

Definition at line 146 of file gnsrecord_pow.c.

{
  const struct GNUNET_CRYPTO_BlindablePublicKey *pk;
 
  pk = (const struct GNUNET_CRYPTO_BlindablePublicKey *) &pow[1];
  return check_signature_identity (pow, pk);
}

References check_signature_identity(), and pk.

Referenced by GNUNET_GNSRECORD_check_pow().

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sign_pow_identity()

static enum GNUNET_GenericReturnValue sign_pow_identity ( const struct GNUNET_CRYPTO_BlindablePrivateKey *  key, struct GNUNET_GNSRECORD_PowP *  pow  )

static

Predate the validity period to prevent rejections due to unsynchronized clocks

Definition at line 266 of file gnsrecord_pow.c.

{
  struct GNUNET_TIME_Absolute ts = GNUNET_TIME_absolute_get ();
  struct GNUNET_GNSRECORD_SignaturePurposePS *rp;
  const struct GNUNET_CRYPTO_BlindablePublicKey *pk;
  size_t ksize;
  char *sig;
  enum GNUNET_GenericReturnValue result;
 
  ts = GNUNET_TIME_absolute_subtract (ts,
                                      GNUNET_TIME_UNIT_WEEKS);
  pk = (const struct GNUNET_CRYPTO_BlindablePublicKey *) &pow[1];
  ksize = GNUNET_CRYPTO_public_key_get_length (pk);
  pow->timestamp = GNUNET_TIME_absolute_hton (ts);
  rp = GNR_create_signature_message (pow);
  sig = ((char*) &pow[1]) + ksize;
  result = GNUNET_CRYPTO_blinded_key_sign_raw_ (key,
                                                &rp->purpose,
                                                (void*) sig);
  GNUNET_free (rp);
  if (result == GNUNET_SYSERR)
    return GNUNET_NO;
  else
    return result;
}

References GNR_create_signature_message(), GNUNET_CRYPTO_blinded_key_sign_raw_(), GNUNET_CRYPTO_public_key_get_length(), GNUNET_free, GNUNET_NO, GNUNET_SYSERR, GNUNET_TIME_absolute_get(), GNUNET_TIME_absolute_hton(), GNUNET_TIME_absolute_subtract(), GNUNET_TIME_UNIT_WEEKS, key, pk, result, rp, and GNUNET_GNSRECORD_PowP::timestamp.

Referenced by sign_pow().

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sign_pow()

static enum GNUNET_GenericReturnValue sign_pow ( const struct GNUNET_CRYPTO_BlindablePrivateKey *  key, struct GNUNET_GNSRECORD_PowP *  pow  )

static

Definition at line 299 of file gnsrecord_pow.c.

{
  struct GNUNET_CRYPTO_BlindablePublicKey *pk;
 
  pk = (struct GNUNET_CRYPTO_BlindablePublicKey *) &pow[1];
  GNUNET_CRYPTO_blindable_key_get_public (key, pk);
  return sign_pow_identity (key, pow);
}

References GNUNET_CRYPTO_blindable_key_get_public(), key, pk, and sign_pow_identity().

Referenced by GNUNET_GNSRECORD_pow_init().

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cmp_pow_value()

static int cmp_pow_value ( const void *  a, const void *  b  )

static

Comparison function for quicksort.

Parameters

a	left element
b	right element

Returns

a-b

Definition at line 354 of file gnsrecord_pow.c.

{
  return (GNUNET_ntohll (*(uint64_t*) a) - GNUNET_ntohll (*(uint64_t*) b));
}

References GNUNET_ntohll().

Referenced by GNUNET_GNSRECORD_pow_round().

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Variable Documentation

salt

struct GNUNET_CRYPTO_PowSalt salt = { "GnsRevocationPow" }

static

Definition at line 84 of file gnsrecord_pow.c.

{ "GnsRevocationPow" };

Referenced by GNUNET_GNSRECORD_check_pow(), and GNUNET_GNSRECORD_pow_round().