13 #include <avr/pgmspace.h>
15 /*****************************************************************************/
17 uint8_t skipjack_ftable[] PROGMEM ={
18 0xa3, 0xd7, 0x09, 0x83, 0xf8, 0x48, 0xf6, 0xf4,
19 0xb3, 0x21, 0x15, 0x78, 0x99, 0xb1, 0xaf, 0xf9,
20 0xe7, 0x2d, 0x4d, 0x8a, 0xce, 0x4c, 0xca, 0x2e,
21 0x52, 0x95, 0xd9, 0x1e, 0x4e, 0x38, 0x44, 0x28,
22 0x0a, 0xdf, 0x02, 0xa0, 0x17, 0xf1, 0x60, 0x68,
23 0x12, 0xb7, 0x7a, 0xc3, 0xe9, 0xfa, 0x3d, 0x53,
24 0x96, 0x84, 0x6b, 0xba, 0xf2, 0x63, 0x9a, 0x19,
25 0x7c, 0xae, 0xe5, 0xf5, 0xf7, 0x16, 0x6a, 0xa2,
26 0x39, 0xb6, 0x7b, 0x0f, 0xc1, 0x93, 0x81, 0x1b,
27 0xee, 0xb4, 0x1a, 0xea, 0xd0, 0x91, 0x2f, 0xb8,
28 0x55, 0xb9, 0xda, 0x85, 0x3f, 0x41, 0xbf, 0xe0,
29 0x5a, 0x58, 0x80, 0x5f, 0x66, 0x0b, 0xd8, 0x90,
30 0x35, 0xd5, 0xc0, 0xa7, 0x33, 0x06, 0x65, 0x69,
31 0x45, 0x00, 0x94, 0x56, 0x6d, 0x98, 0x9b, 0x76,
32 0x97, 0xfc, 0xb2, 0xc2, 0xb0, 0xfe, 0xdb, 0x20,
33 0xe1, 0xeb, 0xd6, 0xe4, 0xdd, 0x47, 0x4a, 0x1d,
34 0x42, 0xed, 0x9e, 0x6e, 0x49, 0x3c, 0xcd, 0x43,
35 0x27, 0xd2, 0x07, 0xd4, 0xde, 0xc7, 0x67, 0x18,
36 0x89, 0xcb, 0x30, 0x1f, 0x8d, 0xc6, 0x8f, 0xaa,
37 0xc8, 0x74, 0xdc, 0xc9, 0x5d, 0x5c, 0x31, 0xa4,
38 0x70, 0x88, 0x61, 0x2c, 0x9f, 0x0d, 0x2b, 0x87,
39 0x50, 0x82, 0x54, 0x64, 0x26, 0x7d, 0x03, 0x40,
40 0x34, 0x4b, 0x1c, 0x73, 0xd1, 0xc4, 0xfd, 0x3b,
41 0xcc, 0xfb, 0x7f, 0xab, 0xe6, 0x3e, 0x5b, 0xa5,
42 0xad, 0x04, 0x23, 0x9c, 0x14, 0x51, 0x22, 0xf0,
43 0x29, 0x79, 0x71, 0x7e, 0xff, 0x8c, 0x0e, 0xe2,
44 0x0c, 0xef, 0xbc, 0x72, 0x75, 0x6f, 0x37, 0xa1,
45 0xec, 0xd3, 0x8e, 0x62, 0x8b, 0x86, 0x10, 0xe8,
46 0x08, 0x77, 0x11, 0xbe, 0x92, 0x4f, 0x24, 0xc5,
47 0x32, 0x36, 0x9d, 0xcf, 0xf3, 0xa6, 0xbb, 0xac,
48 0x5e, 0x6c, 0xa9, 0x13, 0x57, 0x25, 0xb5, 0xe3,
49 0xbd, 0xa8, 0x3a, 0x01, 0x05, 0x59, 0x2a, 0x46
52 /*****************************************************************************/
54 uint16_t skipjack_g(uint16_t g, uint8_t k, uint8_t *key){
55 #define G1 (((uint8_t*)&g)[0])
56 #define G2 (((uint8_t*)&g)[1])
57 /* this could also be rolled up */
58 G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+0)%10]]));
59 G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+1)%10]]));
60 G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+2)%10]]));
61 G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+3)%10]]));
65 /*****************************************************************************/
67 uint16_t skipjack_g_inv(uint16_t g, uint8_t k, uint8_t *key){
68 // #define G1 (((uint8_t)&g)[1])
69 // #define G2 (((uint8_t)&g)[0])
70 /* this could also be rolled up */
71 G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+3)%10]]));
72 G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+2)%10]]));
73 G2 ^= pgm_read_byte_near(&(skipjack_ftable[G1 ^ key[(4*k+1)%10]]));
74 G1 ^= pgm_read_byte_near(&(skipjack_ftable[G2 ^ key[(4*k+0)%10]]));
78 /*****************************************************************************/
80 void skipjack_a(uint16_t* w, uint8_t k, uint8_t* key){
86 w[1] = skipjack_g(w[0],k-1,key);
87 w[0] = t ^ w[1] ^ k<<8;
90 /*****************************************************************************/
92 void skipjack_a_inv(uint16_t* w, uint8_t k, uint8_t* key){
95 w[0] = skipjack_g_inv(w[1],k-1,key);
101 /*****************************************************************************/
103 void skipjack_b(uint16_t* w, uint8_t k, uint8_t* key){
108 w[2] = t ^ k<<8 ^ w[1];
109 w[1] = skipjack_g(t,k-1,key);
112 /*****************************************************************************/
114 void skipjack_b_inv(uint16_t* w, uint8_t k, uint8_t* key){
119 w[0] = skipjack_g_inv(w[1],k-1,key);
120 w[1] = w[0] ^ t ^ k<<8;
123 /*****************************************************************************/
125 * block is 64 bits (=8 bytes) in size, key is 80 bits (=10 bytes) in size.
128 void skipjack_enc(void* block, void* key){
132 skipjack_b((uint16_t*)block, k+1, key);
134 skipjack_a((uint16_t*)block, k+1, key);
139 /*****************************************************************************/
141 * block is 64 bits (=8 bytes) in size, key is 80 bits (=10 bytes) in size.
144 void skipjack_dec(void* block, void* key){
146 for(k=31; k>=0; --k){
148 skipjack_b_inv((uint16_t*)block, k+1, key);
150 skipjack_a_inv((uint16_t*)block, k+1, key);