ringct: import of Shen Noether's ring confidential transactions

1 files changed, 163 insertions, 0 deletions

diff --git a/src/ringct/rctOps.h b/src/ringct/rctOps.h
new file mode 100644
index 000000000..e232dba29
--- /dev/null
+++ b/src/ringct/rctOps.h
@@ -0,0 +1,163 @@
+//#define DBG
+// Copyright (c) 2016, Monero Research Labs
+//
+// Author: Shen Noether <shen.noether@gmx.com>
+//
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+//
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+//
+// 2. 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.
+//
+// 3. Neither the name of the copyright holder 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 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.
+
+#pragma once
+
+#ifndef RCTOPS_H
+#define RCTOPS_H
+
+#include <cstddef>
+#include <mutex>
+#include <vector>
+#include <tuple>
+
+#include "crypto/generic-ops.h"
+
+extern "C" {
+#include "crypto/random.h"
+#include "crypto/keccak.h"
+#include "rctCryptoOps.h"
+}
+#include "crypto/crypto.h"
+
+#include "rctTypes.h"
+
+//Define this flag when debugging to get additional info on the console
+#ifdef DBG
+#define DP(x) dp(x)
+#else
+#define DP(x)
+#endif
+
+using namespace std;
+using namespace crypto;
+
+namespace rct {
+
+    //Various key initialization functions
+
+    //Creates a zero scalar
+    key zero();
+    void zero(key &z);
+    //Creates a zero elliptic curve point
+    key identity();
+    void identity(key &Id);
+    //copies a scalar or point
+    void copy(key &AA, const key &A);
+    key copy(const key & AA);
+    //initializes a key matrix;
+    //first parameter is rows, 
+    //second is columns
+    keyM keyMInit(int, int);
+
+    //Various key generation functions        
+
+    //generates a random scalar which can be used as a secret key or mask
+    key skGen();
+    void skGen(key &);
+    
+    //generates a vector of secret keys of size "int"
+    keyV skvGen(int );
+    
+    //generates a random curve point (for testing)
+    key pkGen();
+    //generates a random secret and corresponding public key
+    void skpkGen(key &sk, key &pk);
+    tuple<key, key> skpkGen();
+    //generates a <secret , public> / Pedersen commitment to the amount
+    tuple<ctkey, ctkey> ctskpkGen(xmr_amount amount);
+    //this one is mainly for testing, can take arbitrary amounts..
+    tuple<ctkey, ctkey> ctskpkGen(key bH);
+    //generates a random uint long long
+    xmr_amount randXmrAmount(xmr_amount upperlimit);
+
+    //Scalar multiplications of curve points        
+
+    //does a * G where a is a scalar and G is the curve basepoint
+    void scalarmultBase(key & aG, const key &a);
+    key scalarmultBase(const key & a);
+    //does a * P where a is a scalar and P is an arbitrary point
+    void scalarmultKey(key &aP, const key &P, const key &a);
+    key scalarmultKey(const key &P, const key &a);
+    //Computes aH where H= toPoint(cn_fast_hash(G)), G the basepoint
+    key scalarmultH(const key & a);
+
+    //Curve addition / subtractions
+
+    //for curve points: AB = A + B
+    void addKeys(key &AB, const key &A, const key &B);
+    //aGB = aG + B where a is a scalar, G is the basepoint, and B is a point
+    void addKeys1(key &aGB, const key &a, const key & B);
+    //aGbB = aG + bB where a, b are scalars, G is the basepoint and B is a point
+    void addKeys2(key &aGbB, const key &a, const key &b, const key &B);
+    //Does some precomputation to make addKeys3 more efficient
+    // input B a curve point and output a ge_dsmp which has precomputation applied
+    void precomp(ge_dsmp rv, const key &B);
+    //aAbB = a*A + b*B where a, b are scalars, A, B are curve points
+    //B must be input after applying "precomp"
+    void addKeys3(key &aAbB, const key &a, const key &A, const key &b, const ge_dsmp B);
+    //AB = A - B where A, B are curve points
+    void subKeys(key &AB, const key &A, const  key &B);
+    //checks if A, B are equal as curve points
+    bool equalKeys(const key & A, const key & B);
+
+    //Hashing - cn_fast_hash
+    //be careful these are also in crypto namespace
+    //cn_fast_hash for arbitrary l multiples of 32 bytes 
+    void cn_fast_hash(key &hash, const void * data, const size_t l);
+    void hash_to_scalar(key &hash, const void * data, const size_t l);
+    //cn_fast_hash for a 32 byte key
+    void cn_fast_hash(key &hash, const key &in);
+    void hash_to_scalar(key &hash, const key &in);
+    //cn_fast_hash for a 32 byte key
+    key cn_fast_hash(const key &in);
+    key hash_to_scalar(const key &in);
+    //for mg sigs
+    key cn_fast_hash128(const void * in);
+    key hash_to_scalar128(const void * in);
+    key cn_fast_hash(ctkeyV PC);
+    key hash_to_scalar(ctkeyV PC);
+
+    //returns hashToPoint as described in https://github.com/ShenNoether/ge_fromfe_writeup 
+    key hashToPointSimple(const key &in);
+    key hashToPoint(const key &in);
+    key hashToPoint2(const key &in);
+    void hashToPoint(key &out, const key &in);
+
+    //sums a vector of curve points (for scalars use sc_add)
+    void sumKeys(key & Csum, const key &Cis);
+
+    //Elliptic Curve Diffie Helman: encodes and decodes the amount b and mask a
+    // where C= aG + bH
+    void ecdhEncode(ecdhTuple & unmasked, const key & receiverPk);
+    void ecdhDecode(ecdhTuple & masked, const key & receiverSk);
+}
+#endif  /* RCTOPS_H */