[linux-2.6-block.git] / include / crypto / internal / ecc.h

/*
 * Copyright (c) 2013, Kenneth MacKay
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *  * Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *  * 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, 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 OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef _CRYPTO_ECC_H
#define _CRYPTO_ECC_H

#include <crypto/ecc_curve.h>
#include <asm/unaligned.h>

/* One digit is u64 qword. */
#define ECC_CURVE_NIST_P192_DIGITS  3
#define ECC_CURVE_NIST_P256_DIGITS  4
#define ECC_CURVE_NIST_P384_DIGITS  6
#define ECC_CURVE_NIST_P521_DIGITS  9
#define ECC_MAX_DIGITS              DIV_ROUND_UP(521, 64) /* NIST P521 */

#define ECC_DIGITS_TO_BYTES_SHIFT 3

#define ECC_MAX_BYTES (ECC_MAX_DIGITS << ECC_DIGITS_TO_BYTES_SHIFT)

#define ECC_POINT_INIT(x, y, ndigits)	(struct ecc_point) { x, y, ndigits }

/**
 * ecc_swap_digits() - Copy ndigits from big endian array to native array
 * @in:       Input array
 * @out:      Output array
 * @ndigits:  Number of digits to copy
 */
static inline void ecc_swap_digits(const void *in, u64 *out, unsigned int ndigits)
{
	const __be64 *src = (__force __be64 *)in;
	int i;

	for (i = 0; i < ndigits; i++)
		out[i] = get_unaligned_be64(&src[ndigits - 1 - i]);
}

/**
 * ecc_digits_from_bytes() - Create ndigits-sized digits array from byte array
 * @in:       Input byte array
 * @nbytes    Size of input byte array
 * @out       Output digits array
 * @ndigits:  Number of digits to create from byte array
 */
static inline void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes,
					 u64 *out, unsigned int ndigits)
{
	unsigned int o = nbytes & 7;
	__be64 msd = 0;

	if (o) {
		memcpy((u8 *)&msd + sizeof(msd) - o, in, o);
		out[--ndigits] = be64_to_cpu(msd);
		in += o;
	}
	ecc_swap_digits(in, out, ndigits);
}

/**
 * ecc_is_key_valid() - Validate a given ECDH private key
 *
 * @curve_id:		id representing the curve to use
 * @ndigits:		curve's number of digits
 * @private_key:	private key to be used for the given curve
 * @private_key_len:	private key length
 *
 * Returns 0 if the key is acceptable, a negative value otherwise
 */
int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
		     const u64 *private_key, unsigned int private_key_len);

/**
 * ecc_gen_privkey() -  Generates an ECC private key.
 * The private key is a random integer in the range 0 < random < n, where n is a
 * prime that is the order of the cyclic subgroup generated by the distinguished
 * point G.
 * @curve_id:		id representing the curve to use
 * @ndigits:		curve number of digits
 * @private_key:	buffer for storing the generated private key
 *
 * Returns 0 if the private key was generated successfully, a negative value
 * if an error occurred.
 */
int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits,
		    u64 *private_key);

/**
 * ecc_make_pub_key() - Compute an ECC public key
 *
 * @curve_id:		id representing the curve to use
 * @ndigits:		curve's number of digits
 * @private_key:	pregenerated private key for the given curve
 * @public_key:		buffer for storing the generated public key
 *
 * Returns 0 if the public key was generated successfully, a negative value
 * if an error occurred.
 */
int ecc_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
		     const u64 *private_key, u64 *public_key);

/**
 * crypto_ecdh_shared_secret() - Compute a shared secret
 *
 * @curve_id:		id representing the curve to use
 * @ndigits:		curve's number of digits
 * @private_key:	private key of part A
 * @public_key:		public key of counterpart B
 * @secret:		buffer for storing the calculated shared secret
 *
 * Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
 * before using it for symmetric encryption or HMAC.
 *
 * Returns 0 if the shared secret was generated successfully, a negative value
 * if an error occurred.
 */
int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
			      const u64 *private_key, const u64 *public_key,
			      u64 *secret);

/**
 * ecc_is_pubkey_valid_partial() - Partial public key validation
 *
 * @curve:		elliptic curve domain parameters
 * @pk:			public key as a point
 *
 * Valdiate public key according to SP800-56A section 5.6.2.3.4 ECC Partial
 * Public-Key Validation Routine.
 *
 * Note: There is no check that the public key is in the correct elliptic curve
 * subgroup.
 *
 * Return: 0 if validation is successful, -EINVAL if validation is failed.
 */
int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
				struct ecc_point *pk);

/**
 * ecc_is_pubkey_valid_full() - Full public key validation
 *
 * @curve:		elliptic curve domain parameters
 * @pk:			public key as a point
 *
 * Valdiate public key according to SP800-56A section 5.6.2.3.3 ECC Full
 * Public-Key Validation Routine.
 *
 * Return: 0 if validation is successful, -EINVAL if validation is failed.
 */
int ecc_is_pubkey_valid_full(const struct ecc_curve *curve,
			     struct ecc_point *pk);

/**
 * vli_is_zero() - Determine is vli is zero
 *
 * @vli:		vli to check.
 * @ndigits:		length of the @vli
 */
bool vli_is_zero(const u64 *vli, unsigned int ndigits);

/**
 * vli_cmp() - compare left and right vlis
 *
 * @left:		vli
 * @right:		vli
 * @ndigits:		length of both vlis
 *
 * Returns sign of @left - @right, i.e. -1 if @left < @right,
 * 0 if @left == @right, 1 if @left > @right.
 */
int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits);

/**
 * vli_sub() - Subtracts right from left
 *
 * @result:		where to write result
 * @left:		vli
 * @right		vli
 * @ndigits:		length of all vlis
 *
 * Note: can modify in-place.
 *
 * Return: carry bit.
 */
u64 vli_sub(u64 *result, const u64 *left, const u64 *right,
	    unsigned int ndigits);

/**
 * vli_from_be64() - Load vli from big-endian u64 array
 *
 * @dest:		destination vli
 * @src:		source array of u64 BE values
 * @ndigits:		length of both vli and array
 */
void vli_from_be64(u64 *dest, const void *src, unsigned int ndigits);

/**
 * vli_from_le64() - Load vli from little-endian u64 array
 *
 * @dest:		destination vli
 * @src:		source array of u64 LE values
 * @ndigits:		length of both vli and array
 */
void vli_from_le64(u64 *dest, const void *src, unsigned int ndigits);

/**
 * vli_mod_inv() - Modular inversion
 *
 * @result:		where to write vli number
 * @input:		vli value to operate on
 * @mod:		modulus
 * @ndigits:		length of all vlis
 */
void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,
		 unsigned int ndigits);

/**
 * vli_mod_mult_slow() - Modular multiplication
 *
 * @result:		where to write result value
 * @left:		vli number to multiply with @right
 * @right:		vli number to multiply with @left
 * @mod:		modulus
 * @ndigits:		length of all vlis
 *
 * Note: Assumes that mod is big enough curve order.
 */
void vli_mod_mult_slow(u64 *result, const u64 *left, const u64 *right,
		       const u64 *mod, unsigned int ndigits);

/**
 * vli_num_bits() - Counts the number of bits required for vli.
 *
 * @vli:		vli to check.
 * @ndigits:		Length of the @vli
 *
 * Return: The number of bits required to represent @vli.
 */
unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits);

/**
 * ecc_aloc_point() - Allocate ECC point.
 *
 * @ndigits:		Length of vlis in u64 qwords.
 *
 * Return: Pointer to the allocated point or NULL if allocation failed.
 */
struct ecc_point *ecc_alloc_point(unsigned int ndigits);

/**
 * ecc_free_point() - Free ECC point.
 *
 * @p:			The point to free.
 */
void ecc_free_point(struct ecc_point *p);

/**
 * ecc_point_is_zero() - Check if point is zero.
 *
 * @p:			Point to check for zero.
 *
 * Return: true if point is the point at infinity, false otherwise.
 */
bool ecc_point_is_zero(const struct ecc_point *point);

/**
 * ecc_point_mult_shamir() - Add two points multiplied by scalars
 *
 * @result:		resulting point
 * @x:			scalar to multiply with @p
 * @p:			point to multiply with @x
 * @y:			scalar to multiply with @q
 * @q:			point to multiply with @y
 * @curve:		curve
 *
 * Returns result = x * p + x * q over the curve.
 * This works faster than two multiplications and addition.
 */
void ecc_point_mult_shamir(const struct ecc_point *result,
			   const u64 *x, const struct ecc_point *p,
			   const u64 *y, const struct ecc_point *q,
			   const struct ecc_curve *curve);

#endif
Commit	Line	Data
3c4b2390 SB	1	/*
	2	* Copyright (c) 2013, Kenneth MacKay
	3	* All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions are
	7	* met:
	8	* * Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* * Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	*
	14	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	15	* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	16	* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	17	* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	18	* HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	19	* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	20	* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	21	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	22	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	23	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	24	* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	25	*/
	26	#ifndef _CRYPTO_ECC_H
	27	#define _CRYPTO_ECC_H
	28
14bb7676	29	#include <crypto/ecc_curve.h>
0469dede	30	#include <asm/unaligned.h>
14bb7676	31
0d7a7864	32	/* One digit is u64 qword. */
d5c3b178 KC	33	#define ECC_CURVE_NIST_P192_DIGITS 3
d5c3b178 KC	34	#define ECC_CURVE_NIST_P256_DIGITS 4
149ca161	35	#define ECC_CURVE_NIST_P384_DIGITS 6
e7fb0627 SB	36	#define ECC_CURVE_NIST_P521_DIGITS 9
e7fb0627 SB	37	#define ECC_MAX_DIGITS DIV_ROUND_UP(521, 64) /* NIST P521 */
3c4b2390 SB	38
	39	#define ECC_DIGITS_TO_BYTES_SHIFT 3
	40
4e660291 SB	41	#define ECC_MAX_BYTES (ECC_MAX_DIGITS << ECC_DIGITS_TO_BYTES_SHIFT)
4e660291 SB	42
0d7a7864 VC	43	#define ECC_POINT_INIT(x, y, ndigits) (struct ecc_point) { x, y, ndigits }
0d7a7864 VC	44
4e660291 SB	45	/**
	46	* ecc_swap_digits() - Copy ndigits from big endian array to native array
	47	* @in: Input array
	48	* @out: Output array
	49	* @ndigits: Number of digits to copy
	50	*/
0469dede	51	static inline void ecc_swap_digits(const void in, u64 out, unsigned int ndigits)
4e660291 SB	52	{
	53	const __be64 src = (__force __be64 )in;
	54	int i;
	55
	56	for (i = 0; i < ndigits; i++)
0469dede	57	out[i] = get_unaligned_be64(&src[ndigits - 1 - i]);
4e660291 SB	58	}
4e660291 SB	59
d67c96fb SB	60	/**
	61	* ecc_digits_from_bytes() - Create ndigits-sized digits array from byte array
	62	* @in: Input byte array
	63	* @nbytes Size of input byte array
	64	* @out Output digits array
	65	* @ndigits: Number of digits to create from byte array
	66	*/
	67	static inline void ecc_digits_from_bytes(const u8 *in, unsigned int nbytes,
	68	u64 *out, unsigned int ndigits)
	69	{
	70	unsigned int o = nbytes & 7;
	71	__be64 msd = 0;
	72
	73	if (o) {
	74	memcpy((u8 *)&msd + sizeof(msd) - o, in, o);
	75	out[--ndigits] = be64_to_cpu(msd);
	76	in += o;
	77	}
	78	ecc_swap_digits(in, out, ndigits);
	79	}
	80
3c4b2390 SB	81	/**
	82	* ecc_is_key_valid() - Validate a given ECDH private key
	83	*
	84	* @curve_id: id representing the curve to use
c0ca1215	85	* @ndigits: curve's number of digits
3c4b2390	86	* @private_key: private key to be used for the given curve
c0ca1215	87	* @private_key_len: private key length
3c4b2390 SB	88	*
	89	* Returns 0 if the key is acceptable, a negative value otherwise
	90	*/
	91	int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
ad269597	92	const u64 *private_key, unsigned int private_key_len);
3c4b2390	93
6755fd26 TDA	94	/**
	95	* ecc_gen_privkey() - Generates an ECC private key.
	96	* The private key is a random integer in the range 0 < random < n, where n is a
	97	* prime that is the order of the cyclic subgroup generated by the distinguished
	98	* point G.
	99	* @curve_id: id representing the curve to use
	100	* @ndigits: curve number of digits
	101	* @private_key: buffer for storing the generated private key
	102	*
	103	* Returns 0 if the private key was generated successfully, a negative value
	104	* if an error occurred.
	105	*/
01474b70 SB	106	int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits,
01474b70 SB	107	u64 *private_key);
6755fd26	108
3c4b2390	109	/**
7380c56d	110	* ecc_make_pub_key() - Compute an ECC public key
3c4b2390 SB	111	*
3c4b2390 SB	112	* @curve_id: id representing the curve to use
c0ca1215	113	* @ndigits: curve's number of digits
3c4b2390	114	* @private_key: pregenerated private key for the given curve
c0ca1215	115	* @public_key: buffer for storing the generated public key
3c4b2390 SB	116	*
	117	* Returns 0 if the public key was generated successfully, a negative value
	118	* if an error occurred.
	119	*/
7380c56d TDA	120	int ecc_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
7380c56d TDA	121	const u64 private_key, u64 public_key);
3c4b2390 SB	122
3c4b2390 SB	123	/**
8f44df15	124	* crypto_ecdh_shared_secret() - Compute a shared secret
3c4b2390 SB	125	*
3c4b2390 SB	126	* @curve_id: id representing the curve to use
c0ca1215	127	* @ndigits: curve's number of digits
3c4b2390	128	* @private_key: private key of part A
3c4b2390	129	* @public_key: public key of counterpart B
3c4b2390	130	* @secret: buffer for storing the calculated shared secret
3c4b2390	131	*
8f44df15	132	* Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
3c4b2390 SB	133	* before using it for symmetric encryption or HMAC.
	134	*
	135	* Returns 0 if the shared secret was generated successfully, a negative value
	136	* if an error occurred.
	137	*/
8f44df15	138	int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
ad269597 TDA	139	const u64 private_key, const u64 public_key,
ad269597 TDA	140	u64 *secret);
4a2289da VC	141
	142	/**
	143	* ecc_is_pubkey_valid_partial() - Partial public key validation
	144	*
	145	* @curve: elliptic curve domain parameters
	146	* @pk: public key as a point
	147	*
	148	* Valdiate public key according to SP800-56A section 5.6.2.3.4 ECC Partial
	149	* Public-Key Validation Routine.
	150	*
	151	* Note: There is no check that the public key is in the correct elliptic curve
	152	* subgroup.
	153	*
	154	* Return: 0 if validation is successful, -EINVAL if validation is failed.
	155	*/
	156	int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
	157	struct ecc_point *pk);
	158
6914dd53 SM	159	/**
	160	* ecc_is_pubkey_valid_full() - Full public key validation
	161	*
	162	* @curve: elliptic curve domain parameters
	163	* @pk: public key as a point
	164	*
	165	* Valdiate public key according to SP800-56A section 5.6.2.3.3 ECC Full
	166	* Public-Key Validation Routine.
	167	*
	168	* Return: 0 if validation is successful, -EINVAL if validation is failed.
	169	*/
	170	int ecc_is_pubkey_valid_full(const struct ecc_curve *curve,
	171	struct ecc_point *pk);
	172
4a2289da VC	173	/**
	174	* vli_is_zero() - Determine is vli is zero
	175	*
	176	* @vli: vli to check.
	177	* @ndigits: length of the @vli
	178	*/
	179	bool vli_is_zero(const u64 *vli, unsigned int ndigits);
	180
	181	/**
	182	* vli_cmp() - compare left and right vlis
	183	*
	184	* @left: vli
	185	* @right: vli
	186	* @ndigits: length of both vlis
	187	*
	188	* Returns sign of @left - @right, i.e. -1 if @left < @right,
	189	* 0 if @left == @right, 1 if @left > @right.
	190	*/
	191	int vli_cmp(const u64 left, const u64 right, unsigned int ndigits);
	192
	193	/**
	194	* vli_sub() - Subtracts right from left
	195	*
	196	* @result: where to write result
	197	* @left: vli
	198	* @right vli
	199	* @ndigits: length of all vlis
	200	*
	201	* Note: can modify in-place.
	202	*
	203	* Return: carry bit.
	204	*/
	205	u64 vli_sub(u64 result, const u64 left, const u64 *right,
	206	unsigned int ndigits);
	207
0d7a7864 VC	208	/**
	209	* vli_from_be64() - Load vli from big-endian u64 array
	210	*
	211	* @dest: destination vli
	212	* @src: source array of u64 BE values
	213	* @ndigits: length of both vli and array
	214	*/
	215	void vli_from_be64(u64 dest, const void src, unsigned int ndigits);
	216
	217	/**
	218	* vli_from_le64() - Load vli from little-endian u64 array
	219	*
	220	* @dest: destination vli
	221	* @src: source array of u64 LE values
	222	* @ndigits: length of both vli and array
	223	*/
	224	void vli_from_le64(u64 dest, const void src, unsigned int ndigits);
	225
4a2289da VC	226	/**
	227	* vli_mod_inv() - Modular inversion
	228	*
	229	* @result: where to write vli number
	230	* @input: vli value to operate on
	231	* @mod: modulus
	232	* @ndigits: length of all vlis
	233	*/
	234	void vli_mod_inv(u64 result, const u64 input, const u64 *mod,
	235	unsigned int ndigits);
	236
0d7a7864 VC	237	/**
	238	* vli_mod_mult_slow() - Modular multiplication
	239	*
	240	* @result: where to write result value
	241	* @left: vli number to multiply with @right
	242	* @right: vli number to multiply with @left
	243	* @mod: modulus
	244	* @ndigits: length of all vlis
	245	*
	246	* Note: Assumes that mod is big enough curve order.
	247	*/
	248	void vli_mod_mult_slow(u64 result, const u64 left, const u64 *right,
	249	const u64 *mod, unsigned int ndigits);
	250
eaffe377 DA	251	/**
	252	* vli_num_bits() - Counts the number of bits required for vli.
	253	*
	254	* @vli: vli to check.
	255	* @ndigits: Length of the @vli
	256	*
	257	* Return: The number of bits required to represent @vli.
	258	*/
	259	unsigned int vli_num_bits(const u64 *vli, unsigned int ndigits);
	260
	261	/**
	262	* ecc_aloc_point() - Allocate ECC point.
	263	*
	264	* @ndigits: Length of vlis in u64 qwords.
	265	*
	266	* Return: Pointer to the allocated point or NULL if allocation failed.
	267	*/
	268	struct ecc_point *ecc_alloc_point(unsigned int ndigits);
	269
	270	/**
	271	* ecc_free_point() - Free ECC point.
	272	*
	273	* @p: The point to free.
	274	*/
	275	void ecc_free_point(struct ecc_point *p);
	276
	277	/**
	278	* ecc_point_is_zero() - Check if point is zero.
	279	*
	280	* @p: Point to check for zero.
	281	*
	282	* Return: true if point is the point at infinity, false otherwise.
	283	*/
	284	bool ecc_point_is_zero(const struct ecc_point *point);
	285
0d7a7864 VC	286	/**
	287	* ecc_point_mult_shamir() - Add two points multiplied by scalars
	288	*
	289	* @result: resulting point
	290	* @x: scalar to multiply with @p
	291	* @p: point to multiply with @x
	292	* @y: scalar to multiply with @q
	293	* @q: point to multiply with @y
	294	* @curve: curve
	295	*
	296	* Returns result = x * p + x * q over the curve.
	297	* This works faster than two multiplications and addition.
	298	*/
	299	void ecc_point_mult_shamir(const struct ecc_point *result,
	300	const u64 x, const struct ecc_point p,
	301	const u64 y, const struct ecc_point q,
	302	const struct ecc_curve *curve);
eaffe377	303
3c4b2390	304	#endif