2 * Copyright (c) 2013, Kenneth MacKay
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29 /* One digit is u64 qword. */
30 #define ECC_CURVE_NIST_P192_DIGITS 3
31 #define ECC_CURVE_NIST_P256_DIGITS 4
32 #define ECC_MAX_DIGITS (512 / 64)
34 #define ECC_DIGITS_TO_BYTES_SHIFT 3
36 #define ECC_MAX_BYTES (ECC_MAX_DIGITS << ECC_DIGITS_TO_BYTES_SHIFT)
39 * struct ecc_point - elliptic curve point in affine coordinates
41 * @x: X coordinate in vli form.
42 * @y: Y coordinate in vli form.
43 * @ndigits: Length of vlis in u64 qwords.
51 #define ECC_POINT_INIT(x, y, ndigits) (struct ecc_point) { x, y, ndigits }
54 * struct ecc_curve - definition of elliptic curve
56 * @name: Short name of the curve.
57 * @g: Generator point of the curve.
58 * @p: Prime number, if Barrett's reduction is used for this curve
59 * pre-calculated value 'mu' is appended to the @p after ndigits.
60 * Use of Barrett's reduction is heuristically determined in
62 * @n: Order of the curve group.
63 * @a: Curve parameter a.
64 * @b: Curve parameter b.
76 * ecc_swap_digits() - Copy ndigits from big endian array to native array
79 * @ndigits: Number of digits to copy
81 static inline void ecc_swap_digits(const u64 *in, u64 *out, unsigned int ndigits)
83 const __be64 *src = (__force __be64 *)in;
86 for (i = 0; i < ndigits; i++)
87 out[i] = be64_to_cpu(src[ndigits - 1 - i]);
91 * ecc_get_curve() - Get a curve given its curve_id
92 * @curve_id: Id of the curve
94 * Returns pointer to the curve data, NULL if curve is not available
96 const struct ecc_curve *ecc_get_curve(unsigned int curve_id);
99 * ecc_is_key_valid() - Validate a given ECDH private key
101 * @curve_id: id representing the curve to use
102 * @ndigits: curve's number of digits
103 * @private_key: private key to be used for the given curve
104 * @private_key_len: private key length
106 * Returns 0 if the key is acceptable, a negative value otherwise
108 int ecc_is_key_valid(unsigned int curve_id, unsigned int ndigits,
109 const u64 *private_key, unsigned int private_key_len);
112 * ecc_gen_privkey() - Generates an ECC private key.
113 * The private key is a random integer in the range 0 < random < n, where n is a
114 * prime that is the order of the cyclic subgroup generated by the distinguished
116 * @curve_id: id representing the curve to use
117 * @ndigits: curve number of digits
118 * @private_key: buffer for storing the generated private key
120 * Returns 0 if the private key was generated successfully, a negative value
121 * if an error occurred.
123 int ecc_gen_privkey(unsigned int curve_id, unsigned int ndigits, u64 *privkey);
126 * ecc_make_pub_key() - Compute an ECC public key
128 * @curve_id: id representing the curve to use
129 * @ndigits: curve's number of digits
130 * @private_key: pregenerated private key for the given curve
131 * @public_key: buffer for storing the generated public key
133 * Returns 0 if the public key was generated successfully, a negative value
134 * if an error occurred.
136 int ecc_make_pub_key(const unsigned int curve_id, unsigned int ndigits,
137 const u64 *private_key, u64 *public_key);
140 * crypto_ecdh_shared_secret() - Compute a shared secret
142 * @curve_id: id representing the curve to use
143 * @ndigits: curve's number of digits
144 * @private_key: private key of part A
145 * @public_key: public key of counterpart B
146 * @secret: buffer for storing the calculated shared secret
148 * Note: It is recommended that you hash the result of crypto_ecdh_shared_secret
149 * before using it for symmetric encryption or HMAC.
151 * Returns 0 if the shared secret was generated successfully, a negative value
152 * if an error occurred.
154 int crypto_ecdh_shared_secret(unsigned int curve_id, unsigned int ndigits,
155 const u64 *private_key, const u64 *public_key,
159 * ecc_is_pubkey_valid_partial() - Partial public key validation
161 * @curve: elliptic curve domain parameters
162 * @pk: public key as a point
164 * Valdiate public key according to SP800-56A section 5.6.2.3.4 ECC Partial
165 * Public-Key Validation Routine.
167 * Note: There is no check that the public key is in the correct elliptic curve
170 * Return: 0 if validation is successful, -EINVAL if validation is failed.
172 int ecc_is_pubkey_valid_partial(const struct ecc_curve *curve,
173 struct ecc_point *pk);
176 * ecc_is_pubkey_valid_full() - Full public key validation
178 * @curve: elliptic curve domain parameters
179 * @pk: public key as a point
181 * Valdiate public key according to SP800-56A section 5.6.2.3.3 ECC Full
182 * Public-Key Validation Routine.
184 * Return: 0 if validation is successful, -EINVAL if validation is failed.
186 int ecc_is_pubkey_valid_full(const struct ecc_curve *curve,
187 struct ecc_point *pk);
190 * vli_is_zero() - Determine is vli is zero
192 * @vli: vli to check.
193 * @ndigits: length of the @vli
195 bool vli_is_zero(const u64 *vli, unsigned int ndigits);
198 * vli_cmp() - compare left and right vlis
202 * @ndigits: length of both vlis
204 * Returns sign of @left - @right, i.e. -1 if @left < @right,
205 * 0 if @left == @right, 1 if @left > @right.
207 int vli_cmp(const u64 *left, const u64 *right, unsigned int ndigits);
210 * vli_sub() - Subtracts right from left
212 * @result: where to write result
215 * @ndigits: length of all vlis
217 * Note: can modify in-place.
221 u64 vli_sub(u64 *result, const u64 *left, const u64 *right,
222 unsigned int ndigits);
225 * vli_from_be64() - Load vli from big-endian u64 array
227 * @dest: destination vli
228 * @src: source array of u64 BE values
229 * @ndigits: length of both vli and array
231 void vli_from_be64(u64 *dest, const void *src, unsigned int ndigits);
234 * vli_from_le64() - Load vli from little-endian u64 array
236 * @dest: destination vli
237 * @src: source array of u64 LE values
238 * @ndigits: length of both vli and array
240 void vli_from_le64(u64 *dest, const void *src, unsigned int ndigits);
243 * vli_mod_inv() - Modular inversion
245 * @result: where to write vli number
246 * @input: vli value to operate on
248 * @ndigits: length of all vlis
250 void vli_mod_inv(u64 *result, const u64 *input, const u64 *mod,
251 unsigned int ndigits);
254 * vli_mod_mult_slow() - Modular multiplication
256 * @result: where to write result value
257 * @left: vli number to multiply with @right
258 * @right: vli number to multiply with @left
260 * @ndigits: length of all vlis
262 * Note: Assumes that mod is big enough curve order.
264 void vli_mod_mult_slow(u64 *result, const u64 *left, const u64 *right,
265 const u64 *mod, unsigned int ndigits);
268 * ecc_point_mult_shamir() - Add two points multiplied by scalars
270 * @result: resulting point
271 * @x: scalar to multiply with @p
272 * @p: point to multiply with @x
273 * @y: scalar to multiply with @q
274 * @q: point to multiply with @y
277 * Returns result = x * p + x * q over the curve.
278 * This works faster than two multiplications and addition.
280 void ecc_point_mult_shamir(const struct ecc_point *result,
281 const u64 *x, const struct ecc_point *p,
282 const u64 *y, const struct ecc_point *q,
283 const struct ecc_curve *curve);