cvsroot/spritz/spritz%2B%2B.h

/* spritz++ */
/* (C)2015 Marc Alexander Lehmann, all rights reserved */

#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];

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

  // add additional entropy
  void put (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:	1.2
Committed:	Fri Jan 9 09:12:18 2015 UTC (9 years, 6 months ago) by root
Content type:	text/plain
Branch:	MAIN
Changes since 1.1:	+3 -0 lines
Log Message:	* empty log message *
#	Content
1	/* spritz++ */
2	/* (C)2015 Marc Alexander Lehmann, all rights reserved */
3
4	#include <assert.h>
5	#include <stdint.h>
6	#include <sys/types.h>
7
8	struct spritz
9	{
10	enum { N = 256 };
11
12	uint8_t a, i, j, k, z, w;
13	uint8_t S[N];
14
15	spritz ()
16	{
17	a =
18	i =
19	j =
20	k =
21	z = 0;
22	w = 1;
23
24	uint_fast8_t v = N - 1;
25	do
26	S[v] = v;
27	while (v--);
28	}
29
30	void update ()
31	{
32	i += w;
33	j = k + S[j + S[i]];
34	k = k + i + S[j];
35	swap (S[i], S[j]);
36	}
37
38	void whip (uint_fast16_t r)
39	{
40	while (r--)
41	update ();
42
43	w += 2;
44	}
45
46	static void swap (uint8_t &a, uint8_t &b)
47	{
48	uint8_t c = a;
49	a = b;
50	b = c;
51	}
52
53	void crush ()
54	{
55	for (uint_fast16_t v = 0; v < (N >> 1); ++v)
56	if (S[v] > S[N - 1 - v])
57	swap (S[v], S[N - 1 - v]);
58	}
59
60	void shuffle ()
61	{
62	whip (2 * N); crush ();
63	whip (2 * N); crush ();
64	whip (2 * N);
65
66	a = 0;
67	}
68
69	void shuffle_absorb ()
70	{
71	if (a == (N >> 1))
72	shuffle ();
73	}
74
75	void absorb_nibble (uint8_t x)
76	{
77	shuffle_absorb ();
78
79	swap (S[a], S[(N >> 1) + x]);
80	++a;
81	}
82
83	void absorb_byte (uint8_t b)
84	{
85	absorb_nibble (b & 15);
86	absorb_nibble (b >> 4);
87	}
88
89	void absorb (const void *I, size_t I_len)
90	{
91	uint8_t i = (uint8_t )I;
92
93	while (I_len--)
94	absorb_byte (*i++);
95	}
96
97	void absorb_stop ()
98	{
99	shuffle_absorb ();
100
101	++a;
102	}
103
104	// commonly used helper function
105	void absorb_stop (const void *I, size_t I_len)
106	{
107	absorb (I, I_len);
108	absorb_stop ();
109	}
110
111	void shuffle_squeeze ()
112	{
113	if (a)
114	shuffle ();
115	}
116
117	uint8_t output ()
118	{
119	return S[j + S[i + S[z + k]]];
120	}
121
122	// slightly faster internal helper, drip without squeeze preparation
123	uint8_t drip_nosqueeze ()
124	{
125	update ();
126	return output ();
127	}
128
129	void squeeze (void *P, size_t P_len)
130	{
131	shuffle_squeeze ();
132
133	uint8_t p = (uint8_t )P;
134
135	while (P_len--)
136	*p++ = drip_nosqueeze ();
137	}
138
139	uint8_t drip ()
140	{
141	shuffle_squeeze ();
142
143	return drip_nosqueeze ();
144	}
145	};
146
147	// what follows is wrappers that make using spritz easier and less error-prone
148
149	// spritz-xor variant of cipher
150	struct spritz_xor : protected spritz
151	{
152	// key K required, IV optional
153	spritz_xor (const void K, size_t K_len, const void IV = 0, size_t IV_len = 0)
154	{
155	absorb (K, K_len);
156
157	if (IV)
158	{
159	absorb_stop ();
160	absorb (IV, IV_len);
161	}
162
163	shuffle_squeeze ();
164	}
165
166	// can be called multiple times/incrementally
167	// can work inplace
168	// works for both encryption and decryption
169	void crypt (const void I, void O, size_t len)
170	{
171	const uint8_t i = (const uint8_t )I;
172	uint8_t o = ( uint8_t )O;
173
174	while (len--)
175	o++ = i++ ^ drip_nosqueeze ();
176	}
177	};
178
179	struct spritz_hash : protected spritz
180	{
181	spritz_hash ()
182	{
183	}
184
185	// can be called multiple times/incrementally
186	void add (const void *M, size_t M_len)
187	{
188	absorb (M, M_len);
189	}
190
191	// must be called at most once at the end
192	void hash (void *H, size_t H_len)
193	{
194	absorb_stop ();
195	assert (H_len <= 0xff);
196	absorb_byte (H_len);
197
198	squeeze (H, H_len);
199	}
200	};
201
202	struct spritz_mac : protected spritz_hash
203	{
204	spritz_mac (const void *K, size_t K_len)
205	{
206	absorb_stop (K, K_len);
207	}
208
209	// use add to incrementally add data
210	using spritz_hash::add;
211
212	// must be called at most once at the end
213	void mac (void *H, size_t H_len)
214	{
215	hash (H, H_len);
216	}
217	};
218
219	struct spritz_aead : protected spritz_mac
220	{
221	spritz_aead (const void *K, size_t K_len)
222	: spritz_mac (K, K_len)
223	{
224	}
225
226	// must be called after construction, before data
227	void nonce (const void *N, size_t N_len)
228	{
229	absorb_stop (N, N_len);
230	}
231
232	// must be called after nonce, before crypt
233	void associated_data (const void *D, size_t D_len)
234	{
235	absorb_stop (D, D_len);
236	}
237
238	// must be called after data, only once, before mac
239	// works for both encryption and decryption
240	void crypt (const void I, void O, size_t len)
241	{
242	const uint8_t i = (const uint8_t )I;
243	uint8_t o = ( uint8_t )O;
244
245	uint8_t x[N >> 2];
246
247	while (len)
248	{
249	uint8_t l = len > sizeof (x) ? sizeof (x) : len;
250	len -= l;
251
252	squeeze (x, l);
253
254	for (uint_fast8_t j = 0; j < l; ++j)
255	absorb_byte (o++ = i++ ^ x[j]);
256	}
257	}
258
259	// call mac() at most once at the end
260	using spritz_mac::mac;
261	};
262
263	struct spritz_drbg : protected spritz
264	{
265	// seed optional, can be done via put
266	spritz_drbg (const void *S = 0, size_t S_len = 0)
267	{
268	absorb (S, S_len);
269	}
270
271	// add additional entropy
272	void put (const void *S, size_t S_len)
273	{
274	absorb (S, S_len);
275	}
276
277	// get random bytes
278	void get (void *R, size_t R_len)
279	{
280	squeeze (R, R_len);
281	}
282	};
283