spritz/spritz%2B%2B.h

/* spritz++, C++ header-only implementation
 *
 * Copyright (c) 2015 Marc Alexander Lehmann <libev@schmorp.de>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modifica-
 * tion, are permitted provided that the following conditions are met:
 *
 *   1.  Redistributions of source code must retain the above copyright notice,
 *       this list of conditions and the following disclaimer.
 *
 *   2.  Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
 * CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO
 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
 * CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
 * ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Alternatively, the contents of this file may be used under the terms of
 * the GNU General Public License ("GPL") version 2 or any later version,
 * in which case the provisions of the GPL are applicable instead of
 * the above. If you wish to allow the use of your version of this file
 * only under the terms of the GPL and not to allow others to use your
 * version of this file under the BSD license, indicate your decision
 * by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL. If you do not delete the
 * provisions above, a recipient may use your version of this file under
 * either the BSD or the GPL.
 */

#include <assert.h>
#include <stdint.h>
#include <sys/types.h>

struct spritz
{
  enum { N = 256 };

  uint8_t a, i, j, k, z, w;
  uint8_t s[N];

  // helper to reduce index to uint8_t
  uint8_t &S (uint8_t i)
  {
    return s[i];
  }

  spritz ()
  {
    a =
    i =
    j =
    k =
    z = 0;
    w = 1;

    uint_fast8_t v = N - 1;
    do
      S(v) = v;
    while (v--);
  }

  void update ()
  {
    i += w;
    j = k + S(j + S(i));
    k = k + i + S(j);
    swap (S(i), S(j));
  }

  void whip (uint_fast16_t r)
  {
    while (r--)
      update ();

    w += 2;
  }

  static void swap (uint8_t &a, uint8_t &b)
  {
    uint8_t c = a;
            a = b;
            b = c;
  }

  void crush ()
  {
    for (uint_fast16_t v = 0; v < (N >> 1); ++v)
      if (S(v) > S(N - 1 - v))
        swap (S(v), S(N - 1 - v));
  }

  void shuffle ()
  {
    whip (2 * N); crush ();
    whip (2 * N); crush ();
    whip (2 * N);

    a = 0;
  }

  void shuffle_absorb ()
  {
    if (a == (N >> 1))
      shuffle ();
  }

  void absorb_nibble (uint8_t x)
  {
    shuffle_absorb ();

    swap (S(a), S((N >> 1) + x));
    ++a;
  }

  void absorb_byte (uint8_t b)
  {
    absorb_nibble (b & 15);
    absorb_nibble (b >> 4);
  }
  
  void absorb (const void *I, size_t I_len)
  {
    uint8_t *i = (uint8_t *)I;

    while (I_len--)
      absorb_byte (*i++);
  }

  void absorb_stop ()
  {
    shuffle_absorb ();

    ++a;
  }

  // commonly used helper function
  void absorb_stop (const void *I, size_t I_len)
  {
    absorb (I, I_len);
    absorb_stop ();
  }

  void shuffle_squeeze ()
  {
    if (a)
      shuffle ();
  }

  uint8_t output ()
  {
    return z = S(j + S(i + S(z + k)));
  }

  // slightly faster internal helper, drip without squeeze preparation
  uint8_t drip_nosqueeze ()
  {
    update ();
    return output ();
  }

  void squeeze (void *P, size_t P_len)
  {
    shuffle_squeeze ();

    uint8_t *p = (uint8_t *)P;

    while (P_len--)
      *p++ = drip_nosqueeze ();
  }

  uint8_t drip ()
  {
    shuffle_squeeze ();

    return drip_nosqueeze ();
  }
};

// what follows is wrappers that make using spritz easier and less error-prone

// spritz-xor variant of cipher
struct spritz_xor : protected spritz
{
  // key K required, IV optional
  spritz_xor (const void *K, size_t K_len, const void *IV = 0, size_t IV_len = 0)
  {
    absorb (K, K_len);

    if (IV)
      {
        absorb_stop ();
        absorb (IV, IV_len);
      }

    shuffle_squeeze ();
  }

  // can be called multiple times/incrementally
  // can work inplace
  // works for both encryption and decryption
  void crypt (const void *I, void *O, size_t len)
  {
    const uint8_t *i = (const uint8_t *)I;
          uint8_t *o = (      uint8_t *)O;

    while (len--)
      *o++ = *i++ ^ drip_nosqueeze ();
  }
};

struct spritz_hash : protected spritz
{
  spritz_hash ()
  {
  }

  // can be called multiple times/incrementally
  void add (const void *M, size_t M_len)
  {
    absorb (M, M_len);
  }

  // must be called at most once at the end
  void hash (void *H, size_t H_len)
  {
    absorb_stop ();
    assert (H_len <= 0xff);
    absorb_byte (H_len);

    squeeze (H, H_len);
  }
};

struct spritz_mac : protected spritz_hash
{
  spritz_mac (const void *K, size_t K_len)
  {
    absorb_stop (K, K_len);
  }

  // use add to incrementally add data
  using spritz_hash::add;

  // must be called at most once at the end
  void mac (void *H, size_t H_len)
  {
    hash (H, H_len);
  }
};

struct spritz_aead : protected spritz_mac
{
  spritz_aead (const void *K, size_t K_len)
  : spritz_mac (K, K_len)
  {
  }

  // must be called after construction, before data
  void nonce (const void *N, size_t N_len)
  {
    absorb_stop (N, N_len);
  }

  // must be called after nonce, before crypt
  void associated_data (const void *D, size_t D_len)
  {
    absorb_stop (D, D_len);
  }

  // must be called after data, only once, before mac
  // works for both encryption and decryption
  void crypt (const void *I, void *O, size_t len)
  {
    const uint8_t *i = (const uint8_t *)I;
          uint8_t *o = (      uint8_t *)O;

    uint8_t x[N >> 2];

    while (len)
      {
        uint8_t l = len > sizeof (x) ? sizeof (x) : len;
        len -= l;

        squeeze (x, l);

        for (uint_fast8_t j = 0; j < l; ++j)
          absorb_byte (*o++ = *i++ ^ x[j]);
      }
  }

  // call mac() at most once at the end
  using spritz_mac::mac;
};

struct spritz_prng : protected spritz
{
  // seed optional, can be done via put
  spritz_prng (const void *S = 0, size_t S_len = 0)
  {
    absorb (S, S_len);
  }

  // add additional entropy
  void add (const void *S, size_t S_len)
  {
    absorb (S, S_len);
  }

  // get random bytes
  void get (void *R, size_t R_len)
  {
    squeeze (R, R_len);
  }
};

Revision:	1.4
Committed:	Sat Jan 10 04:14:21 2015 UTC (9 years, 5 months ago) by root
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rel-1_02, rel-1_0, rel-0_2, rel-1_01, HEAD
Changes since 1.3:	+18 -12 lines
Log Message:	* empty log message *
#	Content
1	/* spritz++, C++ header-only implementation
2	*
3	* Copyright (c) 2015 Marc Alexander Lehmann <libev@schmorp.de>
4	* All rights reserved.
5	*
6	* Redistribution and use in source and binary forms, with or without modifica-
7	* tion, are permitted provided that the following conditions are met:
8	*
9	* 1. Redistributions of source code must retain the above copyright notice,
10	* this list of conditions and the following disclaimer.
11	*
12	* 2. Redistributions in binary form must reproduce the above copyright
13	* notice, this list of conditions and the following disclaimer in the
14	* documentation and/or other materials provided with the distribution.
15	*
16	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
17	* WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MER-
18	* CHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
19	* EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPE-
20	* CIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
21	* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
22	* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
23	* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTH-
24	* ERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
25	* OF THE POSSIBILITY OF SUCH DAMAGE.
26	*
27	* Alternatively, the contents of this file may be used under the terms of
28	* the GNU General Public License ("GPL") version 2 or any later version,
29	* in which case the provisions of the GPL are applicable instead of
30	* the above. If you wish to allow the use of your version of this file
31	* only under the terms of the GPL and not to allow others to use your
32	* version of this file under the BSD license, indicate your decision
33	* by deleting the provisions above and replace them with the notice
34	* and other provisions required by the GPL. If you do not delete the
35	* provisions above, a recipient may use your version of this file under
36	* either the BSD or the GPL.
37	*/
38
39	#include <assert.h>
40	#include <stdint.h>
41	#include <sys/types.h>
42
43	struct spritz
44	{
45	enum { N = 256 };
46
47	uint8_t a, i, j, k, z, w;
48	uint8_t s[N];
49
50	// helper to reduce index to uint8_t
51	uint8_t &S (uint8_t i)
52	{
53	return s[i];
54	}
55
56	spritz ()
57	{
58	a =
59	i =
60	j =
61	k =
62	z = 0;
63	w = 1;
64
65	uint_fast8_t v = N - 1;
66	do
67	S(v) = v;
68	while (v--);
69	}
70
71	void update ()
72	{
73	i += w;
74	j = k + S(j + S(i));
75	k = k + i + S(j);
76	swap (S(i), S(j));
77	}
78
79	void whip (uint_fast16_t r)
80	{
81	while (r--)
82	update ();
83
84	w += 2;
85	}
86
87	static void swap (uint8_t &a, uint8_t &b)
88	{
89	uint8_t c = a;
90	a = b;
91	b = c;
92	}
93
94	void crush ()
95	{
96	for (uint_fast16_t v = 0; v < (N >> 1); ++v)
97	if (S(v) > S(N - 1 - v))
98	swap (S(v), S(N - 1 - v));
99	}
100
101	void shuffle ()
102	{
103	whip (2 * N); crush ();
104	whip (2 * N); crush ();
105	whip (2 * N);
106
107	a = 0;
108	}
109
110	void shuffle_absorb ()
111	{
112	if (a == (N >> 1))
113	shuffle ();
114	}
115
116	void absorb_nibble (uint8_t x)
117	{
118	shuffle_absorb ();
119
120	swap (S(a), S((N >> 1) + x));
121	++a;
122	}
123
124	void absorb_byte (uint8_t b)
125	{
126	absorb_nibble (b & 15);
127	absorb_nibble (b >> 4);
128	}
129
130	void absorb (const void *I, size_t I_len)
131	{
132	uint8_t i = (uint8_t )I;
133
134	while (I_len--)
135	absorb_byte (*i++);
136	}
137
138	void absorb_stop ()
139	{
140	shuffle_absorb ();
141
142	++a;
143	}
144
145	// commonly used helper function
146	void absorb_stop (const void *I, size_t I_len)
147	{
148	absorb (I, I_len);
149	absorb_stop ();
150	}
151
152	void shuffle_squeeze ()
153	{
154	if (a)
155	shuffle ();
156	}
157
158	uint8_t output ()
159	{
160	return z = S(j + S(i + S(z + k)));
161	}
162
163	// slightly faster internal helper, drip without squeeze preparation
164	uint8_t drip_nosqueeze ()
165	{
166	update ();
167	return output ();
168	}
169
170	void squeeze (void *P, size_t P_len)
171	{
172	shuffle_squeeze ();
173
174	uint8_t p = (uint8_t )P;
175
176	while (P_len--)
177	*p++ = drip_nosqueeze ();
178	}
179
180	uint8_t drip ()
181	{
182	shuffle_squeeze ();
183
184	return drip_nosqueeze ();
185	}
186	};
187
188	// what follows is wrappers that make using spritz easier and less error-prone
189
190	// spritz-xor variant of cipher
191	struct spritz_xor : protected spritz
192	{
193	// key K required, IV optional
194	spritz_xor (const void K, size_t K_len, const void IV = 0, size_t IV_len = 0)
195	{
196	absorb (K, K_len);
197
198	if (IV)
199	{
200	absorb_stop ();
201	absorb (IV, IV_len);
202	}
203
204	shuffle_squeeze ();
205	}
206
207	// can be called multiple times/incrementally
208	// can work inplace
209	// works for both encryption and decryption
210	void crypt (const void I, void O, size_t len)
211	{
212	const uint8_t i = (const uint8_t )I;
213	uint8_t o = ( uint8_t )O;
214
215	while (len--)
216	o++ = i++ ^ drip_nosqueeze ();
217	}
218	};
219
220	struct spritz_hash : protected spritz
221	{
222	spritz_hash ()
223	{
224	}
225
226	// can be called multiple times/incrementally
227	void add (const void *M, size_t M_len)
228	{
229	absorb (M, M_len);
230	}
231
232	// must be called at most once at the end
233	void hash (void *H, size_t H_len)
234	{
235	absorb_stop ();
236	assert (H_len <= 0xff);
237	absorb_byte (H_len);
238
239	squeeze (H, H_len);
240	}
241	};
242
243	struct spritz_mac : protected spritz_hash
244	{
245	spritz_mac (const void *K, size_t K_len)
246	{
247	absorb_stop (K, K_len);
248	}
249
250	// use add to incrementally add data
251	using spritz_hash::add;
252
253	// must be called at most once at the end
254	void mac (void *H, size_t H_len)
255	{
256	hash (H, H_len);
257	}
258	};
259
260	struct spritz_aead : protected spritz_mac
261	{
262	spritz_aead (const void *K, size_t K_len)
263	: spritz_mac (K, K_len)
264	{
265	}
266
267	// must be called after construction, before data
268	void nonce (const void *N, size_t N_len)
269	{
270	absorb_stop (N, N_len);
271	}
272
273	// must be called after nonce, before crypt
274	void associated_data (const void *D, size_t D_len)
275	{
276	absorb_stop (D, D_len);
277	}
278
279	// must be called after data, only once, before mac
280	// works for both encryption and decryption
281	void crypt (const void I, void O, size_t len)
282	{
283	const uint8_t i = (const uint8_t )I;
284	uint8_t o = ( uint8_t )O;
285
286	uint8_t x[N >> 2];
287
288	while (len)
289	{
290	uint8_t l = len > sizeof (x) ? sizeof (x) : len;
291	len -= l;
292
293	squeeze (x, l);
294
295	for (uint_fast8_t j = 0; j < l; ++j)
296	absorb_byte (o++ = i++ ^ x[j]);
297	}
298	}
299
300	// call mac() at most once at the end
301	using spritz_mac::mac;
302	};
303
304	struct spritz_prng : protected spritz
305	{
306	// seed optional, can be done via put
307	spritz_prng (const void *S = 0, size_t S_len = 0)
308	{
309	absorb (S, S_len);
310	}
311
312	// add additional entropy
313	void add (const void *S, size_t S_len)
314	{
315	absorb (S, S_len);
316	}
317
318	// get random bytes
319	void get (void *R, size_t R_len)
320	{
321	squeeze (R, R_len);
322	}
323	};
324