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Diffstat (limited to 'crypto/ecc.h')
| -rw-r--r-- | crypto/ecc.h | 259 |
1 files changed, 259 insertions, 0 deletions
diff --git a/crypto/ecc.h b/crypto/ecc.h new file mode 100644 index 000000000..d4e546b9a --- /dev/null +++ b/crypto/ecc.h @@ -0,0 +1,259 @@ +/* + * 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 + +/* One digit is u64 qword. */ +#define ECC_CURVE_NIST_P192_DIGITS 3 +#define ECC_CURVE_NIST_P256_DIGITS 4 +#define ECC_MAX_DIGITS (512 / 64) + +#define ECC_DIGITS_TO_BYTES_SHIFT 3 + +/** + * struct ecc_point - elliptic curve point in affine coordinates + * + * @x: X coordinate in vli form. + * @y: Y coordinate in vli form. + * @ndigits: Length of vlis in u64 qwords. + */ +struct ecc_point { + u64 *x; + u64 *y; + u8 ndigits; +}; + +#define ECC_POINT_INIT(x, y, ndigits) (struct ecc_point) { x, y, ndigits } + +/** + * struct ecc_curve - definition of elliptic curve + * + * @name: Short name of the curve. + * @g: Generator point of the curve. + * @p: Prime number, if Barrett's reduction is used for this curve + * pre-calculated value 'mu' is appended to the @p after ndigits. + * Use of Barrett's reduction is heuristically determined in + * vli_mmod_fast(). + * @n: Order of the curve group. + * @a: Curve parameter a. + * @b: Curve parameter b. + */ +struct ecc_curve { + char *name; + struct ecc_point g; + u64 *p; + u64 *n; + u64 *a; + u64 *b; +}; + +/** + * 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 *privkey); + +/** + * 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); + +/** + * 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 |