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 // 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 #include #include #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; 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_