keyhole logo

Functions

Diffie-Hellman functions

Functions

const DH_METHOD * DH_ltm_method (void)
DH * DH_new (void)
DH * DH_new_method (ENGINE *engine)
void DH_free (DH *dh)
int DH_up_ref (DH *dh)
int DH_size (const DH *dh)
int DH_set_ex_data (DH *dh, int idx, void *data)
void * DH_get_ex_data (DH *dh, int idx)
int DH_generate_parameters_ex (DH *dh, int prime_len, int generator, BN_GENCB *cb)
int DH_check_pubkey (const DH *dh, const BIGNUM *pub_key, int *codes)
int DH_generate_key (DH *dh)
int DH_compute_key (unsigned char *shared_key, const BIGNUM *peer_pub_key, DH *dh)
int DH_set_method (DH *dh, const DH_METHOD *method)
const DH_METHOD * DH_null_method (void)
void DH_set_default_method (const DH_METHOD *meth)
const DH_METHOD * DH_get_default_method (void)

Detailed Description

See the DH - Diffie-Hellman key exchange for description and examples.


Function Documentation

int DH_check_pubkey ( const DH *  dh,
const BIGNUM *  pub_key,
int *  codes 
)

Check that the public key is sane.

Parameters:
dhthe local peer DH parameters.
pub_keythe remote peer public key parameters.
codesreturn that the failures of the pub_key are.
Returns:
1 on success, 0 on failure and *codes is set the the combined fail check for the public key

Checks that the function performs are:

  • pub_key is not negative
  • pub_key > 1 and pub_key < p - 1, to avoid small subgroups attack.
  • if g == 2, pub_key have more then one bit set, if bits set is 1, log_2(pub_key) is trival

int DH_compute_key ( unsigned char *  shared_key,
const BIGNUM *  peer_pub_key,
DH *  dh 
)

Complute the shared secret key.

Parameters:
shared_keythe resulting shared key, need to be at least DH_size() large.
peer_pub_keythe peer's public key.
dhthe dh key pair.
Returns:
1 on success.

Checks that the pubkey passed in is valid using DH_check_pubkey().

void DH_free ( DH *  dh )

Free a DH object and release related resources, like ENGINE, that the object was using.

Parameters:
dhobject to be freed.
int DH_generate_key ( DH *  dh )

Generate a new DH private-public key pair. The dh parameter must be allocted first with DH_new(). dh->p and dp->g must be set.

Parameters:
dhdh parameter.
Returns:
1 on success.
int DH_generate_parameters_ex ( DH *  dh,
int  prime_len,
int  generator,
BN_GENCB *  cb 
)

Generate DH parameters for the DH object give parameters.

Parameters:
dhThe DH object to generate parameters for.
prime_lenlength of the prime
generatorgenerator, g
cbCallback parameters to show progress, can be NULL.
Returns:
the maximum size in bytes of the out data.
const DH_METHOD* DH_get_default_method ( void   )

Return the default DH implementation.

Returns:
pointer to a DH_METHOD.
void* DH_get_ex_data ( DH *  dh,
int  idx 
)

Get the data for index idx in the DH object.

Parameters:
dhDH object.
idxindex to get the data for.
Returns:
the object store in index idx
const DH_METHOD* DH_ltm_method ( void   )

DH implementation using libtommath.

Returns:
the DH_METHOD for the DH implementation using libtommath.
DH* DH_new ( void   )

Create a new DH object using DH_new_method(NULL), see DH_new_method().

Returns:
a newly allocated DH object.
DH* DH_new_method ( ENGINE *  engine )

Create a new DH object from the given engine, if the NULL is used, the default engine is used. Free the DH object with DH_free().

Parameters:
engineThe engine to use to allocate the DH object.
Returns:
a newly allocated DH object.
const DH_METHOD* DH_null_method ( void   )

Return the dummy DH implementation.

Returns:
pointer to a DH_METHOD.
void DH_set_default_method ( const DH_METHOD *  meth )

Set the default DH implementation.

Parameters:
methpointer to a DH_METHOD.
int DH_set_ex_data ( DH *  dh,
int  idx,
void *  data 
)

Set the data index idx in the DH object to data.

Parameters:
dhDH object.
idxindex to set the data for.
datadata to store for the index idx.
Returns:
1 on success.
int DH_set_method ( DH *  dh,
const DH_METHOD *  method 
)

Set a new method for the DH keypair.

Parameters:
dhdh parameter.
methodthe new method for the DH parameter.
Returns:
1 on success.
int DH_size ( const DH *  dh )

The maximum output size of the DH_compute_key() function.

Parameters:
dhThe DH object to get the size from.
Returns:
the maximum size in bytes of the out data.
int DH_up_ref ( DH *  dh )

Add a reference to the DH object. The object should be free with DH_free() to drop the reference.

Parameters:
dhthe object to increase the reference count too.
Returns:
the updated reference count, can't safely be used except for debug printing.

Generated on Wed Nov 9 2011 16:14:48 for Heimdal crypto library by doxygen 1.7.2