BaseCryptLib/Pk/CryptDh.c

	CryptDh.c revision 4fd606d1f5abe38e1f42c38de1d2e895166bd0f4
45e9809aff7304721fddb95654901b32195c9c7avboxsync/** @file
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Diffie-Hellman Wrapper Implementation over OpenSSL.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsyncCopyright (c) 2010 - 2012, Intel Corporation. All rights reserved.<BR>
45e9809aff7304721fddb95654901b32195c9c7avboxsyncThis program and the accompanying materials
45e9809aff7304721fddb95654901b32195c9c7avboxsyncare licensed and made available under the terms and conditions of the BSD License
45e9809aff7304721fddb95654901b32195c9c7avboxsyncwhich accompanies this distribution.  The full text of the license may be found at
45e9809aff7304721fddb95654901b32195c9c7avboxsynchttp://opensource.org/licenses/bsd-license.php
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsyncTHE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
45e9809aff7304721fddb95654901b32195c9c7avboxsyncWITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync**/
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync#include "InternalCryptLib.h"
45e9809aff7304721fddb95654901b32195c9c7avboxsync#include <openssl/dh.h>
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync/**
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Allocates and Initializes one Diffie-Hellman Context for subsequent use.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @return  Pointer to the Diffie-Hellman Context that has been initialized.
45e9809aff7304721fddb95654901b32195c9c7avboxsync           If the allocations fails, DhNew() returns NULL.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync**/
45e9809aff7304721fddb95654901b32195c9c7avboxsyncVOID *
45e9809aff7304721fddb95654901b32195c9c7avboxsyncEFIAPI
45e9809aff7304721fddb95654901b32195c9c7avboxsyncDhNew (
45e9809aff7304721fddb95654901b32195c9c7avboxsync  VOID
45e9809aff7304721fddb95654901b32195c9c7avboxsync  )
45e9809aff7304721fddb95654901b32195c9c7avboxsync{
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  // Allocates & Initializes DH Context by OpenSSL DH_new()
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  return (VOID *)DH_new ();
45e9809aff7304721fddb95654901b32195c9c7avboxsync}
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync/**
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Release the specified DH context.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If DhContext is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]  DhContext  Pointer to the DH context to be released.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync**/
45e9809aff7304721fddb95654901b32195c9c7avboxsyncVOID
45e9809aff7304721fddb95654901b32195c9c7avboxsyncEFIAPI
45e9809aff7304721fddb95654901b32195c9c7avboxsyncDhFree (
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN  VOID  *DhContext
45e9809aff7304721fddb95654901b32195c9c7avboxsync  )
45e9809aff7304721fddb95654901b32195c9c7avboxsync{
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  // Free OpenSSL DH Context
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  DH_free ((DH *)DhContext);
45e9809aff7304721fddb95654901b32195c9c7avboxsync}
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync/**
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Generates DH parameter.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Given generator g, and length of prime number p in bits, this function generates p,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  and sets DH context according to value of g and p.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Before this function can be invoked, pseudorandom number generator must be correctly
45e9809aff7304721fddb95654901b32195c9c7avboxsync  initialized by RandomSeed().
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If DhContext is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If Prime is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in, out]  DhContext    Pointer to the DH context.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]       Generator    Value of generator.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]       PrimeLength  Length in bits of prime to be generated.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[out]      Prime        Pointer to the buffer to receive the generated prime number.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval TRUE   DH pamameter generation succeeded.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  Value of Generator is not supported.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  PRNG fails to generate random prime number with PrimeLength.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync**/
45e9809aff7304721fddb95654901b32195c9c7avboxsyncBOOLEAN
45e9809aff7304721fddb95654901b32195c9c7avboxsyncEFIAPI
45e9809aff7304721fddb95654901b32195c9c7avboxsyncDhGenerateParameter (
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN OUT  VOID   *DhContext,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN      UINTN  Generator,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN      UINTN  PrimeLength,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  OUT     UINT8  *Prime
45e9809aff7304721fddb95654901b32195c9c7avboxsync  )
45e9809aff7304721fddb95654901b32195c9c7avboxsync{
45e9809aff7304721fddb95654901b32195c9c7avboxsync  BOOLEAN RetVal;
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  // Check input parameters.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (DhContext == NULL || Prime == NULL) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (Generator != DH_GENERATOR_2 && Generator != DH_GENERATOR_5) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  RetVal = (BOOLEAN) DH_generate_parameters_ex (DhContext, (UINT32) PrimeLength, (UINT32) Generator, NULL);
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (!RetVal) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  BN_bn2bin (((DH *) DhContext)->p, Prime);
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  return TRUE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync}
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync/**
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Sets generator and prime parameters for DH.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Given generator g, and prime number p, this function and sets DH
45e9809aff7304721fddb95654901b32195c9c7avboxsync  context accordingly.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If DhContext is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If Prime is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in, out]  DhContext    Pointer to the DH context.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]       Generator    Value of generator.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]       PrimeLength  Length in bits of prime to be generated.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]       Prime        Pointer to the prime number.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval TRUE   DH pamameter setting succeeded.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  Value of Generator is not supported.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  Value of Generator is not suitable for the Prime.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  Value of Prime is not a prime number.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  Value of Prime is not a safe prime number.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync**/
45e9809aff7304721fddb95654901b32195c9c7avboxsyncBOOLEAN
45e9809aff7304721fddb95654901b32195c9c7avboxsyncEFIAPI
45e9809aff7304721fddb95654901b32195c9c7avboxsyncDhSetParameter (
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN OUT  VOID         *DhContext,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN      UINTN        Generator,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN      UINTN        PrimeLength,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN      CONST UINT8  *Prime
45e9809aff7304721fddb95654901b32195c9c7avboxsync  )
45e9809aff7304721fddb95654901b32195c9c7avboxsync{
45e9809aff7304721fddb95654901b32195c9c7avboxsync  DH  *Dh;
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  // Check input parameters.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (DhContext == NULL || Prime == NULL) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (Generator != DH_GENERATOR_2 && Generator != DH_GENERATOR_5) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Dh = (DH *) DhContext;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Dh->p = BN_new();
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Dh->g = BN_new();
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  BN_bin2bn (Prime, (UINT32) (PrimeLength / 8), Dh->p);
45e9809aff7304721fddb95654901b32195c9c7avboxsync  BN_set_word (Dh->g, (UINT32) Generator);
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  return TRUE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync}
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync/**
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Generates DH public key.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  This function generates random secret exponent, and computes the public key, which is
45e9809aff7304721fddb95654901b32195c9c7avboxsync  returned via parameter PublicKey and PublicKeySize. DH context is updated accordingly.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If the PublicKey buffer is too small to hold the public key, FALSE is returned and
45e9809aff7304721fddb95654901b32195c9c7avboxsync  PublicKeySize is set to the required buffer size to obtain the public key.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If DhContext is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If PublicKeySize is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If PublicKeySize is large enough but PublicKey is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in, out]  DhContext      Pointer to the DH context.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[out]      PublicKey      Pointer to the buffer to receive generated public key.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in, out]  PublicKeySize  On input, the size of PublicKey buffer in bytes.
45e9809aff7304721fddb95654901b32195c9c7avboxsync                                  On output, the size of data returned in PublicKey buffer in bytes.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval TRUE   DH public key generation succeeded.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  DH public key generation failed.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  PublicKeySize is not large enough.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync**/
45e9809aff7304721fddb95654901b32195c9c7avboxsyncBOOLEAN
45e9809aff7304721fddb95654901b32195c9c7avboxsyncEFIAPI
45e9809aff7304721fddb95654901b32195c9c7avboxsyncDhGenerateKey (
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN OUT  VOID   *DhContext,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  OUT     UINT8  *PublicKey,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN OUT  UINTN  *PublicKeySize
45e9809aff7304721fddb95654901b32195c9c7avboxsync  )
45e9809aff7304721fddb95654901b32195c9c7avboxsync{
45e9809aff7304721fddb95654901b32195c9c7avboxsync  BOOLEAN RetVal;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  DH      *Dh;
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  // Check input parameters.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (DhContext == NULL || PublicKeySize == NULL) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (PublicKey == NULL && *PublicKeySize != 0) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Dh = (DH *) DhContext;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  *PublicKeySize = 0;
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  RetVal = (BOOLEAN) DH_generate_key (DhContext);
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (RetVal) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    BN_bn2bin (Dh->pub_key, PublicKey);
45e9809aff7304721fddb95654901b32195c9c7avboxsync    *PublicKeySize  = BN_num_bytes (Dh->pub_key);
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  return RetVal;
45e9809aff7304721fddb95654901b32195c9c7avboxsync}
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync/**
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Computes exchanged common key.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  Given peer's public key, this function computes the exchanged common key, based on its own
45e9809aff7304721fddb95654901b32195c9c7avboxsync  context including value of prime modulus and random secret exponent.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If DhContext is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If PeerPublicKey is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If KeySize is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  If KeySize is large enough but Key is NULL, then return FALSE.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in, out]  DhContext          Pointer to the DH context.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]       PeerPublicKey      Pointer to the peer's public key.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in]       PeerPublicKeySize  Size of peer's public key in bytes.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[out]      Key                Pointer to the buffer to receive generated key.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @param[in, out]  KeySize            On input, the size of Key buffer in bytes.
45e9809aff7304721fddb95654901b32195c9c7avboxsync                                      On output, the size of data returned in Key buffer in bytes.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval TRUE   DH exchanged key generation succeeded.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  DH exchanged key generation failed.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  @retval FALSE  KeySize is not large enough.
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync**/
45e9809aff7304721fddb95654901b32195c9c7avboxsyncBOOLEAN
45e9809aff7304721fddb95654901b32195c9c7avboxsyncEFIAPI
45e9809aff7304721fddb95654901b32195c9c7avboxsyncDhComputeKey (
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN OUT  VOID         *DhContext,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN      CONST UINT8  *PeerPublicKey,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN      UINTN        PeerPublicKeySize,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  OUT     UINT8        *Key,
45e9809aff7304721fddb95654901b32195c9c7avboxsync  IN OUT  UINTN        *KeySize
45e9809aff7304721fddb95654901b32195c9c7avboxsync  )
45e9809aff7304721fddb95654901b32195c9c7avboxsync{
45e9809aff7304721fddb95654901b32195c9c7avboxsync  BIGNUM  *Bn;
45e9809aff7304721fddb95654901b32195c9c7avboxsync
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  // Check input parameters.
45e9809aff7304721fddb95654901b32195c9c7avboxsync  //
45e9809aff7304721fddb95654901b32195c9c7avboxsync  if (DhContext == NULL || PeerPublicKey == NULL || KeySize == NULL) {
45e9809aff7304721fddb95654901b32195c9c7avboxsync    return FALSE;
45e9809aff7304721fddb95654901b32195c9c7avboxsync  }
45e9809aff7304721fddb95654901b32195c9c7avboxsync
  if (Key == NULL && *KeySize != 0) {
    return FALSE;
  }

  Bn = BN_bin2bn (PeerPublicKey, (UINT32) PeerPublicKeySize, NULL);

  *KeySize = (BOOLEAN) DH_compute_key (Key, Bn, DhContext);

  BN_free (Bn);

  return TRUE;
}