Esempio n. 1
0
void sapphire::initialize(unsigned char *key, unsigned char keysize)
    {
    // Key size may be up to 256 bytes.
    // Pass phrases may be used directly, with longer length
    // compensating for the low entropy expected in such keys.
    // Alternatively, shorter keys hashed from a pass phrase or
    // generated randomly may be used. For random keys, lengths
    // of from 4 to 16 bytes are recommended, depending on how
    // secure you want this to be.

    int i;
    unsigned char toswap, swaptemp, rsum;
    unsigned keypos;

    // If we have been given no key, assume the default hash setup.

    if (keysize < 1)
        {
        hash_init();
        return;
        }

    // Start with cards all in order, one of each.

    for (i=0;i<256;i++)
        cards[i] = i;

    // Swap the card at each position with some other card.

    toswap = 0;
    keypos = 0;         // Start with first byte of user key.
    rsum = 0;
    for (i=255;i>=0;i--)
        {
        toswap = keyrand(i, key, keysize, &rsum, &keypos);
        swaptemp = cards[i];
        cards[i] = cards[toswap];
        cards[toswap] = swaptemp;
        }

    // Initialize the indices and data dependencies.
    // Indices are set to different values instead of all 0
    // to reduce what is known about the state of the cards
    // when the first byte is emitted.

    rotor = cards[1];
    ratchet = cards[3];
    avalanche = cards[5];
    last_plain = cards[7];
    last_cipher = cards[rsum];

    toswap = swaptemp = rsum = 0;
    keypos = 0;
    }
Esempio n. 2
0
SapphireBase::SapphireBase(const byte *key, unsigned int keysize)
	: cards(256)
{
	assert(keysize < 256);
	// Key size may be up to 256 bytes.
	// Pass phrases may be used directly, with longer length
	// compensating for the low entropy expected in such keys.
	// Alternatively, shorter keys hashed from a pass phrase or
	// generated randomly may be used. For random keys, lengths
	// of from 4 to 16 bytes are recommended, depending on how
	// secure you want this to be.

	int i;
	byte rsum;
	unsigned keypos;

	// Start with cards all in order, one of each.

	for (i=0;i<256;i++)
		cards[i] = i;

	// Swap the card at each position with some other card.

	keypos = 0;         // Start with first byte of user key.
	rsum = 0;
	for (i=255;i;i--)
		std::swap(cards[i], cards[keyrand(i, key, keysize, &rsum, &keypos)]);

	// Initialize the indices and data dependencies.
	// Indices are set to different values instead of all 0
	// to reduce what is known about the state of the cards
	// when the first byte is emitted.

	rotor = cards[1];
	ratchet = cards[3];
	avalanche = cards[5];
	last_plain = cards[7];
	last_cipher = cards[rsum];

	rsum = 0;
	keypos = 0;
}