| // Copyright 2012 The Chromium OS Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef LIBWEAVE_THIRD_PARTY_CHROMIUM_P224_H_ |
| #define LIBWEAVE_THIRD_PARTY_CHROMIUM_P224_H_ |
| |
| #include <stddef.h> |
| #include <stdint.h> |
| |
| #include <string> |
| |
| #include "base/strings/string_piece.h" |
| |
| namespace crypto { |
| |
| // P224 implements an elliptic curve group, commonly known as P224 and defined |
| // in FIPS 186-3, section D.2.2. |
| namespace p224 { |
| |
| // An element of the field (ℤ/pℤ) is represented with 8, 28-bit limbs in |
| // little endian order. |
| typedef uint32_t FieldElement[8]; |
| |
| struct Point { |
| // SetFromString the value of the point from the 56 byte, external |
| // representation. The external point representation is an (x, y) pair of a |
| // point on the curve. Each field element is represented as a big-endian |
| // number < p. |
| bool SetFromString(const base::StringPiece& in); |
| |
| // ToString returns an external representation of the Point. |
| std::string ToString() const; |
| |
| // An Point is represented in Jacobian form (x/z², y/z³). |
| FieldElement x, y, z; |
| }; |
| |
| // kScalarBytes is the number of bytes needed to represent an element of the |
| // P224 field. |
| static const size_t kScalarBytes = 28; |
| |
| // ScalarMult computes *out = in*scalar where scalar is a 28-byte, big-endian |
| // number. |
| void ScalarMult(const Point& in, const uint8_t* scalar, Point* out); |
| |
| // ScalarBaseMult computes *out = g*scalar where g is the base point of the |
| // curve and scalar is a 28-byte, big-endian number. |
| void ScalarBaseMult(const uint8_t* scalar, Point* out); |
| |
| // Add computes *out = a+b. |
| void Add(const Point& a, const Point& b, Point* out); |
| |
| // Negate calculates out = -a; |
| void Negate(const Point& a, Point* out); |
| |
| } // namespace p224 |
| |
| } // namespace crypto |
| |
| #endif // LIBWEAVE_THIRD_PARTY_CHROMIUM_P224_H_ |