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Diffstat (limited to 'include/mincrypt/p256.h')
-rw-r--r-- | include/mincrypt/p256.h | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/include/mincrypt/p256.h b/include/mincrypt/p256.h new file mode 100644 index 0000000..465a1b9 --- /dev/null +++ b/include/mincrypt/p256.h @@ -0,0 +1,162 @@ +/* + * Copyright 2013 The Android Open Source Project + * + * 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. + * * Neither the name of Google Inc. nor the names of its contributors may + * be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY Google Inc. ``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 Google Inc. 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 SYSTEM_CORE_INCLUDE_MINCRYPT_LITE_P256_H_ +#define SYSTEM_CORE_INCLUDE_MINCRYPT_LITE_P256_H_ + +// Collection of routines manipulating 256 bit unsigned integers. +// Just enough to implement ecdsa-p256 and related algorithms. + +#include <stdint.h> + +#ifdef __cplusplus +extern "C" { +#endif + +#define P256_BITSPERDIGIT 32 +#define P256_NDIGITS 8 +#define P256_NBYTES 32 + +typedef int p256_err; +typedef uint32_t p256_digit; +typedef int32_t p256_sdigit; +typedef uint64_t p256_ddigit; +typedef int64_t p256_sddigit; + +// Defining p256_int as struct to leverage struct assigment. +typedef struct { + p256_digit a[P256_NDIGITS]; +} p256_int; + +extern const p256_int SECP256r1_n; // Curve order +extern const p256_int SECP256r1_p; // Curve prime +extern const p256_int SECP256r1_b; // Curve param + +// Initialize a p256_int to zero. +void p256_init(p256_int* a); + +// Clear a p256_int to zero. +void p256_clear(p256_int* a); + +// Return bit. Index 0 is least significant. +int p256_get_bit(const p256_int* a, int index); + +// b := a % MOD +void p256_mod( + const p256_int* MOD, + const p256_int* a, + p256_int* b); + +// c := a * (top_b | b) % MOD +void p256_modmul( + const p256_int* MOD, + const p256_int* a, + const p256_digit top_b, + const p256_int* b, + p256_int* c); + +// b := 1 / a % MOD +// MOD best be SECP256r1_n +void p256_modinv( + const p256_int* MOD, + const p256_int* a, + p256_int* b); + +// b := 1 / a % MOD +// MOD best be SECP256r1_n +// Faster than p256_modinv() +void p256_modinv_vartime( + const p256_int* MOD, + const p256_int* a, + p256_int* b); + +// b := a << (n % P256_BITSPERDIGIT) +// Returns the bits shifted out of most significant digit. +p256_digit p256_shl(const p256_int* a, int n, p256_int* b); + +// b := a >> (n % P256_BITSPERDIGIT) +void p256_shr(const p256_int* a, int n, p256_int* b); + +int p256_is_zero(const p256_int* a); +int p256_is_odd(const p256_int* a); +int p256_is_even(const p256_int* a); + +// Returns -1, 0 or 1. +int p256_cmp(const p256_int* a, const p256_int *b); + +// c: = a - b +// Returns -1 on borrow. +int p256_sub(const p256_int* a, const p256_int* b, p256_int* c); + +// c := a + b +// Returns 1 on carry. +int p256_add(const p256_int* a, const p256_int* b, p256_int* c); + +// c := a + (single digit)b +// Returns carry 1 on carry. +int p256_add_d(const p256_int* a, p256_digit b, p256_int* c); + +// ec routines. + +// {out_x,out_y} := nG +void p256_base_point_mul(const p256_int *n, + p256_int *out_x, + p256_int *out_y); + +// {out_x,out_y} := n{in_x,in_y} +void p256_point_mul(const p256_int *n, + const p256_int *in_x, + const p256_int *in_y, + p256_int *out_x, + p256_int *out_y); + +// {out_x,out_y} := n1G + n2{in_x,in_y} +void p256_points_mul_vartime( + const p256_int *n1, const p256_int *n2, + const p256_int *in_x, const p256_int *in_y, + p256_int *out_x, p256_int *out_y); + +// Return whether point {x,y} is on curve. +int p256_is_valid_point(const p256_int* x, const p256_int* y); + +// Outputs big-endian binary form. No leading zero skips. +void p256_to_bin(const p256_int* src, uint8_t dst[P256_NBYTES]); + +// Reads from big-endian binary form, +// thus pre-pad with leading zeros if short. +void p256_from_bin(const uint8_t src[P256_NBYTES], p256_int* dst); + +#define P256_DIGITS(x) ((x)->a) +#define P256_DIGIT(x,y) ((x)->a[y]) + +#define P256_ZERO {{0}} +#define P256_ONE {{1}} + +#ifdef __cplusplus +} +#endif + +#endif // SYSTEM_CORE_INCLUDE_MINCRYPT_LITE_P256_H_ |