1 // SPDX-License-Identifier: BSD-2-Clause
2 /* LibTomCrypt, modular cryptographic library -- Tom St Denis
3  *
4  * LibTomCrypt is a library that provides various cryptographic
5  * algorithms in a highly modular and flexible manner.
6  *
7  * The library is free for all purposes without any express
8  * guarantee it works.
9  */
10 
11 /**
12   @file kasumi.c
13   Implementation of the 3GPP Kasumi block cipher
14   Derived from the 3GPP standard source code
15 */
16 
17 #include "tomcrypt_private.h"
18 
19 #ifdef LTC_KASUMI
20 
21 typedef unsigned u16;
22 
23 #define ROL16(x, y) ((((x)<<(y)) | ((x)>>(16-(y)))) & 0xFFFF)
24 
25 const struct ltc_cipher_descriptor kasumi_desc = {
26    "kasumi",
27    21,
28    16, 16, 8, 8,
29    &kasumi_setup,
30    &kasumi_ecb_encrypt,
31    &kasumi_ecb_decrypt,
32    &kasumi_test,
33    &kasumi_done,
34    &kasumi_keysize,
35    NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL, NULL
36 };
37 
FI(u16 in,u16 subkey)38 static u16 FI( u16 in, u16 subkey )
39 {
40    u16 nine, seven;
41    static const u16 S7[128] = {
42       54, 50, 62, 56, 22, 34, 94, 96, 38, 6, 63, 93, 2, 18,123, 33,
43       55,113, 39,114, 21, 67, 65, 12, 47, 73, 46, 27, 25,111,124, 81,
44       53, 9,121, 79, 52, 60, 58, 48,101,127, 40,120,104, 70, 71, 43,
45       20,122, 72, 61, 23,109, 13,100, 77, 1, 16, 7, 82, 10,105, 98,
46       117,116, 76, 11, 89,106, 0,125,118, 99, 86, 69, 30, 57,126, 87,
47       112, 51, 17, 5, 95, 14, 90, 84, 91, 8, 35,103, 32, 97, 28, 66,
48       102, 31, 26, 45, 75, 4, 85, 92, 37, 74, 80, 49, 68, 29,115, 44,
49       64,107,108, 24,110, 83, 36, 78, 42, 19, 15, 41, 88,119, 59, 3 };
50   static const u16 S9[512] = {
51       167,239,161,379,391,334, 9,338, 38,226, 48,358,452,385, 90,397,
52       183,253,147,331,415,340, 51,362,306,500,262, 82,216,159,356,177,
53       175,241,489, 37,206, 17, 0,333, 44,254,378, 58,143,220, 81,400,
54        95, 3,315,245, 54,235,218,405,472,264,172,494,371,290,399, 76,
55       165,197,395,121,257,480,423,212,240, 28,462,176,406,507,288,223,
56       501,407,249,265, 89,186,221,428,164, 74,440,196,458,421,350,163,
57       232,158,134,354, 13,250,491,142,191, 69,193,425,152,227,366,135,
58       344,300,276,242,437,320,113,278, 11,243, 87,317, 36, 93,496, 27,
59       487,446,482, 41, 68,156,457,131,326,403,339, 20, 39,115,442,124,
60       475,384,508, 53,112,170,479,151,126,169, 73,268,279,321,168,364,
61       363,292, 46,499,393,327,324, 24,456,267,157,460,488,426,309,229,
62       439,506,208,271,349,401,434,236, 16,209,359, 52, 56,120,199,277,
63       465,416,252,287,246, 6, 83,305,420,345,153,502, 65, 61,244,282,
64       173,222,418, 67,386,368,261,101,476,291,195,430, 49, 79,166,330,
65       280,383,373,128,382,408,155,495,367,388,274,107,459,417, 62,454,
66       132,225,203,316,234, 14,301, 91,503,286,424,211,347,307,140,374,
67        35,103,125,427, 19,214,453,146,498,314,444,230,256,329,198,285,
68        50,116, 78,410, 10,205,510,171,231, 45,139,467, 29, 86,505, 32,
69        72, 26,342,150,313,490,431,238,411,325,149,473, 40,119,174,355,
70       185,233,389, 71,448,273,372, 55,110,178,322, 12,469,392,369,190,
71         1,109,375,137,181, 88, 75,308,260,484, 98,272,370,275,412,111,
72       336,318, 4,504,492,259,304, 77,337,435, 21,357,303,332,483, 18,
73        47, 85, 25,497,474,289,100,269,296,478,270,106, 31,104,433, 84,
74       414,486,394, 96, 99,154,511,148,413,361,409,255,162,215,302,201,
75       266,351,343,144,441,365,108,298,251, 34,182,509,138,210,335,133,
76       311,352,328,141,396,346,123,319,450,281,429,228,443,481, 92,404,
77       485,422,248,297, 23,213,130,466, 22,217,283, 70,294,360,419,127,
78       312,377, 7,468,194, 2,117,295,463,258,224,447,247,187, 80,398,
79       284,353,105,390,299,471,470,184, 57,200,348, 63,204,188, 33,451,
80        97, 30,310,219, 94,160,129,493, 64,179,263,102,189,207,114,402,
81       438,477,387,122,192, 42,381, 5,145,118,180,449,293,323,136,380,
82        43, 66, 60,455,341,445,202,432, 8,237, 15,376,436,464, 59,461};
83 
84   /* The sixteen bit input is split into two unequal halves, *
85    * nine bits and seven bits - as is the subkey            */
86 
87   nine  = (u16)(in>>7)&0x1FF;
88   seven = (u16)(in&0x7F);
89 
90   /* Now run the various operations */
91   nine   = (u16)(S9[nine] ^ seven);
92   seven  = (u16)(S7[seven] ^ (nine & 0x7F));
93   seven ^= (subkey>>9);
94   nine  ^= (subkey&0x1FF);
95   nine   = (u16)(S9[nine] ^ seven);
96   seven  = (u16)(S7[seven] ^ (nine & 0x7F));
97   return (u16)(seven<<9) + nine;
98 }
99 
FO(ulong32 in,int round_no,const symmetric_key * key)100 static ulong32 FO( ulong32 in, int round_no, const symmetric_key *key)
101 {
102    u16 left, right;
103 
104   /* Split the input into two 16-bit words */
105   left = (u16)(in>>16);
106   right = (u16) in&0xFFFF;
107 
108   /* Now apply the same basic transformation three times */
109   left ^= key->kasumi.KOi1[round_no];
110   left = FI( left, key->kasumi.KIi1[round_no] );
111   left ^= right;
112 
113   right ^= key->kasumi.KOi2[round_no];
114   right = FI( right, key->kasumi.KIi2[round_no] );
115   right ^= left;
116 
117   left ^= key->kasumi.KOi3[round_no];
118   left = FI( left, key->kasumi.KIi3[round_no] );
119   left ^= right;
120 
121   return (((ulong32)right)<<16)+left;
122 }
123 
FL(ulong32 in,int round_no,const symmetric_key * key)124 static ulong32 FL( ulong32 in, int round_no, const symmetric_key *key )
125 {
126     u16 l, r, a, b;
127     /* split out the left and right halves */
128     l = (u16)(in>>16);
129     r = (u16)(in)&0xFFFF;
130     /* do the FL() operations           */
131     a = (u16) (l & key->kasumi.KLi1[round_no]);
132     r ^= ROL16(a,1);
133     b = (u16)(r | key->kasumi.KLi2[round_no]);
134     l ^= ROL16(b,1);
135     /* put the two halves back together */
136 
137     return (((ulong32)l)<<16) + r;
138 }
139 
kasumi_ecb_encrypt(const unsigned char * pt,unsigned char * ct,const symmetric_key * skey)140 int kasumi_ecb_encrypt(const unsigned char *pt, unsigned char *ct, const symmetric_key *skey)
141 {
142     ulong32 left, right, temp;
143     int n;
144 
145     LTC_ARGCHK(pt   != NULL);
146     LTC_ARGCHK(ct   != NULL);
147     LTC_ARGCHK(skey != NULL);
148 
149     LOAD32H(left, pt);
150     LOAD32H(right, pt+4);
151 
152     for (n = 0; n <= 7; ) {
153         temp = FL(left,  n,   skey);
154         temp = FO(temp,  n++, skey);
155         right ^= temp;
156         temp = FO(right, n,   skey);
157         temp = FL(temp,  n++, skey);
158         left ^= temp;
159     }
160 
161     STORE32H(left, ct);
162     STORE32H(right, ct+4);
163 
164     return CRYPT_OK;
165 }
166 
kasumi_ecb_decrypt(const unsigned char * ct,unsigned char * pt,const symmetric_key * skey)167 int kasumi_ecb_decrypt(const unsigned char *ct, unsigned char *pt, const symmetric_key *skey)
168 {
169     ulong32 left, right, temp;
170     int n;
171 
172     LTC_ARGCHK(pt   != NULL);
173     LTC_ARGCHK(ct   != NULL);
174     LTC_ARGCHK(skey != NULL);
175 
176     LOAD32H(left, ct);
177     LOAD32H(right, ct+4);
178 
179     for (n = 7; n >= 0; ) {
180         temp = FO(right, n,   skey);
181         temp = FL(temp,  n--, skey);
182         left ^= temp;
183         temp = FL(left,  n,   skey);
184         temp = FO(temp,  n--, skey);
185         right ^= temp;
186     }
187 
188     STORE32H(left, pt);
189     STORE32H(right, pt+4);
190 
191     return CRYPT_OK;
192 }
193 
kasumi_setup(const unsigned char * key,int keylen,int num_rounds,symmetric_key * skey)194 int kasumi_setup(const unsigned char *key, int keylen, int num_rounds, symmetric_key *skey)
195 {
196     static const u16 C[8] = { 0x0123,0x4567,0x89AB,0xCDEF, 0xFEDC,0xBA98,0x7654,0x3210 };
197     u16 ukey[8], Kprime[8];
198     int n;
199 
200     LTC_ARGCHK(key  != NULL);
201     LTC_ARGCHK(skey != NULL);
202 
203     if (keylen != 16) {
204        return CRYPT_INVALID_KEYSIZE;
205     }
206 
207     if (num_rounds != 0 && num_rounds != 8) {
208        return CRYPT_INVALID_ROUNDS;
209     }
210 
211     /* Start by ensuring the subkeys are endian correct on a 16-bit basis */
212     for (n = 0; n < 8; n++ ) {
213         ukey[n] = (((u16)key[2*n]) << 8) | key[2*n+1];
214     }
215 
216     /* Now build the K'[] keys */
217     for (n = 0; n < 8; n++) {
218         Kprime[n] = ukey[n] ^ C[n];
219     }
220 
221     /* Finally construct the various sub keys */
222     for(n = 0; n < 8; n++) {
223         skey->kasumi.KLi1[n] = ROL16(ukey[n],1);
224         skey->kasumi.KLi2[n] = Kprime[(n+2)&0x7];
225         skey->kasumi.KOi1[n] = ROL16(ukey[(n+1)&0x7],5);
226         skey->kasumi.KOi2[n] = ROL16(ukey[(n+5)&0x7],8);
227         skey->kasumi.KOi3[n] = ROL16(ukey[(n+6)&0x7],13);
228         skey->kasumi.KIi1[n] = Kprime[(n+4)&0x7];
229         skey->kasumi.KIi2[n] = Kprime[(n+3)&0x7];
230         skey->kasumi.KIi3[n] = Kprime[(n+7)&0x7];
231     }
232 
233     return CRYPT_OK;
234 }
235 
kasumi_done(symmetric_key * skey)236 void kasumi_done(symmetric_key *skey)
237 {
238   LTC_UNUSED_PARAM(skey);
239 }
240 
kasumi_keysize(int * keysize)241 int kasumi_keysize(int *keysize)
242 {
243    LTC_ARGCHK(keysize != NULL);
244    if (*keysize >= 16) {
245       *keysize = 16;
246       return CRYPT_OK;
247    }
248    return CRYPT_INVALID_KEYSIZE;
249 }
250 
kasumi_test(void)251 int kasumi_test(void)
252 {
253 #ifndef LTC_TEST
254    return CRYPT_NOP;
255 #else
256    static const struct {
257       unsigned char key[16], pt[8], ct[8];
258    } tests[] = {
259 
260 {
261    { 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
262    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
263    { 0x4B, 0x58, 0xA7, 0x71, 0xAF, 0xC7, 0xE5, 0xE8 }
264 },
265 
266 {
267    { 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
268    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
269    { 0x7E, 0xEF, 0x11, 0x3C, 0x95, 0xBB, 0x5A, 0x77 }
270 },
271 
272 {
273    { 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
274    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
275    { 0x5F, 0x14, 0x06, 0x86, 0xD7, 0xAD, 0x5A, 0x39 },
276 },
277 
278 {
279    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01 },
280    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
281    { 0x2E, 0x14, 0x91, 0xCF, 0x70, 0xAA, 0x46, 0x5D }
282 },
283 
284 {
285    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x01, 0x00 },
286    { 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00 },
287    { 0xB5, 0x45, 0x86, 0xF4, 0xAB, 0x9A, 0xE5, 0x46 }
288 },
289 
290 };
291    unsigned char buf[2][8];
292    symmetric_key key;
293    int err, x;
294 
295    for (x = 0; x < (int)(sizeof(tests)/sizeof(tests[0])); x++) {
296        if ((err = kasumi_setup(tests[x].key, 16, 0, &key)) != CRYPT_OK) {
297           return err;
298        }
299        if ((err = kasumi_ecb_encrypt(tests[x].pt, buf[0], &key)) != CRYPT_OK) {
300           return err;
301        }
302        if ((err = kasumi_ecb_decrypt(tests[x].ct, buf[1], &key)) != CRYPT_OK) {
303           return err;
304        }
305        if (compare_testvector(buf[1], 8, tests[x].pt, 8, "Kasumi Decrypt", x) ||
306              compare_testvector(buf[0], 8, tests[x].ct, 8, "Kasumi Encrypt", x)) {
307           return CRYPT_FAIL_TESTVECTOR;
308        }
309    }
310    return CRYPT_OK;
311 #endif
312 }
313 
314 #endif
315 
316 /* ref:         $Format:%D$ */
317 /* git commit:  $Format:%H$ */
318 /* commit time: $Format:%ai$ */
319