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_