void EncryptionModeLRW::SetKey (const ConstBufferPtr &key)
{
if (key.Size() != 16)
throw ParameterIncorrect (SRC_POS);
if (!KeySet)
GfContext.Allocate (sizeof (GfCtx));
if (!Gf64TabInit ((unsigned char *) key.Get(), (GfCtx *) (GfContext.Ptr())))
throw bad_alloc();
if (!Gf128Tab64Init ((unsigned char *) key.Get(), (GfCtx *) (GfContext.Ptr())))
throw bad_alloc();
Key.CopyFrom (key);
KeySet = true;
}
BOOL EAInitMode (PCRYPTO_INFO ci)
{
switch (ci->mode)
{
case XTS:
// Secondary key schedule
if (EAInit (ci->ea, ci->k2, ci->ks2) != ERR_SUCCESS)
return FALSE;
/* Note: XTS mode could potentially be initialized with a weak key causing all blocks in one data unit
on the volume to be tweaked with zero tweaks (i.e. 512 bytes of the volume would be encrypted in ECB
mode). However, to create a GostCrypt volume with such a weak key, each human being on Earth would have
to create approximately 11,378,125,361,078,862 (about eleven quadrillion) GostCrypt volumes (provided
that the size of each of the volumes is 1024 terabytes). */
break;
case LRW:
switch (CipherGetBlockSize (EAGetFirstCipher (ci->ea)))
{
case 8:
/* Deprecated/legacy */
return Gf64TabInit (ci->k2, &ci->gf_ctx);
case 16:
return Gf128Tab64Init (ci->k2, &ci->gf_ctx);
default:
GST_THROW_FATAL_EXCEPTION;
}
break;
case CBC:
case INNER_CBC:
case OUTER_CBC:
// The mode does not need to be initialized or is initialized elsewhere
return TRUE;
default:
// Unknown/wrong ID
GST_THROW_FATAL_EXCEPTION;
}
return TRUE;
}
