FourDolphins!

gistfile1.c

#include <stdint.h>
#include <stdio.h>

/* Permutations of {0, ..., 15} */
static const uint8_t SIGMA[14][16] = {
	{  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15 },
	{ 14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3 },
	{ 11,  8, 12,  0,  5,  2, 15, 13, 10, 14,  3,  6,  7,  1,  9,  4 },
	{  7,  9,  3,  1, 13, 12, 11, 14,  2,  6,  5, 10,  4,  0, 15,  8 },
	{  9,  0,  5,  7,  2,  4, 10, 15, 14,  1, 11, 12,  6,  8,  3, 13 },
	{  2, 12,  6, 10,  0, 11,  8,  3,  4, 13,  7,  5, 15, 14,  1,  9 },
	{ 12,  5,  1, 15, 14, 13,  4, 10,  0,  7,  6,  3,  9,  2,  8, 11 },
	{ 13, 11,  7, 14, 12,  1,  3,  9,  5,  0, 15,  4,  8,  6,  2, 10 },
	{  6, 15, 14,  9, 11,  3,  0,  8, 12,  2, 13,  7,  1,  4, 10,  5 },
	{ 10,  2,  8,  4,  7,  6,  1,  5, 15, 11,  9, 14,  3, 12, 13,  0 },
	{  0,  1,  2,  3,  4,  5,  6,  7,  8,  9, 10, 11, 12, 13, 14, 15 },
	{ 14, 10,  4,  8,  9, 15, 13,  6,  1, 12,  0,  2, 11,  7,  5,  3 },
	{ 11,  8, 12,  0,  5,  2, 15, 13, 10, 14,  3,  6,  7,  1,  9,  4 },
	{  7,  9,  3,  1, 13, 12, 11, 14,  2,  6,  5, 10,  4,  0, 15,  8 }
};

/* Constants */
static const uint32_t CST[16] = {
	0x243F6A88, 0x85A308D3, 0x13198A2E, 0x03707344,
	0xA4093822, 0x299F31D0, 0x082EFA98, 0xEC4E6C89,
	0x452821E6, 0x38D01377, 0xBE5466CF, 0x34E90C6C,
	0xC0AC29B7, 0xC97C50DD, 0x3F84D5B5, 0xB5470917
};

#define NROUNDS 14

#define ROTR(x, n) (((x)<<(32-n)) | ((x)>>(n)))
#define ROTL(x, n) (((x)>>(32-n)) | ((x)<<(n)))

void
FourDolphins_Encrypt(uint32_t k[16], uint32_t src[16], uint32_t dst[16])
{
	uint32_t v[16];
	int i;

	for (i = 0; i < 16; i++)
		v[i] = src[i];

#define GE(a, b, c, d, e) do {						\
	v[a] += (k[SIGMA[i][e]] ^ CST[SIGMA[i][e+1]]) + v[b];		\
	v[d] = ROTR(v[d] ^ v[a], 16);					\
	v[c] += v[d];							\
	v[b] = ROTR(v[b] ^ v[c], 12);					\
	v[a] += (k[SIGMA[i][e+1]] ^ CST[SIGMA[i][e]]) + v[b];		\
	v[d] = ROTR(v[d] ^ v[a], 8);					\
	v[c] += v[d];							\
	v[b] = ROTR(v[b] ^ v[c], 7);					\
} while (0)


	for (i = 0; i < NROUNDS; i++) {
		GE(0, 4,  8, 12,  0);
		GE(1, 5,  9, 13,  2);
		GE(2, 6, 10, 14,  4);
		GE(3, 7, 11, 15,  6);
		GE(3, 4,  9, 14, 14);
		GE(2, 7,  8, 13, 12);
		GE(0, 5, 10, 15,  8);
		GE(1, 6, 11, 12, 10);
	}

#undef GE
	for (i = 0; i < 16; i++)
		dst[i] = v[i];
}

void
FourDolphins_Decrypt(uint32_t k[16], uint32_t src[16], uint32_t dst[16])
{
	uint32_t v[16];
	int i;

	for (i = 0; i < 16; i++)
		v[i] = src[i];

#define GD(a, b, c, d, e) do {						\
	v[b] = ROTL(v[b], 7) ^ v[c];					\
	v[c] -= v[d];							\
	v[d] = ROTL(v[d], 8) ^ v[a];					\
	v[a] -= (k[SIGMA[i][e+1]] ^ CST[SIGMA[i][e]]) + v[b];		\
	v[b] = ROTL(v[b], 12) ^ v[c];					\
	v[c] -= v[d];							\
	v[d] = ROTL(v[d], 16) ^ v[a];					\
	v[a] -= (k[SIGMA[i][e]] ^ CST[SIGMA[i][e+1]]) + v[b];		\
} while (0)
		
	for (i = NROUNDS-1; i >= 0; i--) {
		GD(1, 6, 11, 12, 10);
		GD(0, 5, 10, 15,  8);
		GD(2, 7,  8, 13, 12);
		GD(3, 4,  9, 14, 14);
		GD(3, 7, 11, 15,  6);
		GD(2, 6, 10, 14,  4);
		GD(1, 5,  9, 13,  2);
		GD(0, 4,  8, 12,  0);
	}

#undef GD
	for (i = 0; i < 16; i++)
		dst[i] = v[i];
}

void
print16(uint32_t *v)
{
	int i;
	for (i = 0; i < 16; i++)
		printf("%u ", v[i]);
	printf("\n");

}

int
main(void)
{
	uint32_t k[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
	uint32_t src[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};
	uint32_t dst[16] = {0};

	printf("original:\n");
	print16(src);
	FourDolphins_Encrypt(k, src, dst);
	printf("\nencrypted:\n");
	print16(dst);
	FourDolphins_Decrypt(k, dst, dst);
	printf("\ndecrypted:\n");
	print16(dst);

}