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Initial API for Confidential Transactions
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4 files changed

+265
-32
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‎Sources/zkp/Surjection.swift

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//
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// Surjection.swift
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// GigaBitcoin/secp256k1.swift
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//
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// Copyright (c) 2023 GigaBitcoin LLC
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// Distributed under the MIT software license
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//
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// See the accompanying file LICENSE for information
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//
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import Foundation
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import zkp_bindings
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// MARK: - secp256k1 + SurjectionProof
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public extension secp256k1 {
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enum Surjection {
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struct Proof {
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let length = Int(32 * (1 + SECP256K1_SURJECTIONPROOF_MAX_USED_INPUTS))
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/// Total number of input asset tags
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public let nInputs: Int
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/// Bitmap of which input tags are used in the surjection proof
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public let usedInputs: Data
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/// Borromean signature: e0, scalars
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public let rawRepresentation: Data
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/// The index of the actual input that is secretly mapped to the output
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public let inputIndex: Int
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/// The ephemeral asset tag of the output
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public let ephemeralOutputTag: Data
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/// the blinding key of the output
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public let blindingKey: [UInt8]
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/// Surjection proof initialization and generation functions
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@usableFromInline init(
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fixedInputTags: [secp256k1_fixed_asset_tag],
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ephemeralInputTags: [secp256k1_generator],
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inputBlindingKey: [UInt8]
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) throws {
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var outSurjectionProof = secp256k1_surjectionproof()
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var ephemeralOutputTag = secp256k1_generator()
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var outputBlindingKey = [UInt8](repeating: 0, count: 64)
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var outInputIndex = 0
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var fixedOutputTag = secp256k1_fixed_asset_tag()
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var randomSeed: Int8 = 3
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var proofData = [UInt8](repeating: 0, count: length)
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guard secp256k1_surjectionproof_initialize(
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secp256k1.Context.raw,
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&outSurjectionProof,
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&outInputIndex,
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fixedInputTags,
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fixedInputTags.count,
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fixedInputTags.count,
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&fixedOutputTag,
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100,
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&randomSeed
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).boolValue,
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secp256k1_surjectionproof_generate(
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secp256k1.Context.raw,
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&outSurjectionProof,
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ephemeralInputTags,
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ephemeralInputTags.count,
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&ephemeralOutputTag,
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outInputIndex,
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inputBlindingKey,
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&outputBlindingKey
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).boolValue else {
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throw secp256k1Error.underlyingCryptoError
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}
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secp256k1_swift_surjection_proof_parse(&proofData, outSurjectionProof)
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self.blindingKey = outputBlindingKey
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self.nInputs = outSurjectionProof.n_inputs
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self.inputIndex = outInputIndex
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self.usedInputs = Data(outSurjectionProof.used_inputs)
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self.rawRepresentation = Data(proofData)
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self.ephemeralOutputTag = Data(ephemeralOutputTag.data)
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}
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static func verify(
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proof: inout secp256k1_surjectionproof,
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ephemeralInputTags: [secp256k1_generator],
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ephemeralOutputTag: inout secp256k1_generator
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) -> Bool {
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secp256k1_surjectionproof_verify(
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secp256k1.Context.raw,
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&proof,
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ephemeralInputTags,
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ephemeralInputTags.count,
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&ephemeralOutputTag
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).boolValue
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}
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}
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}
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}
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internal extension Data {
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init(_ usedInputs: UsedInputsType) {
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self = Data(Swift.withUnsafeBytes(of: usedInputs) { [UInt8]($0) })
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}
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init(_ ephemeralTag: EphemeralTagType) {
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self = Data(Swift.withUnsafeBytes(of: ephemeralTag) { [UInt8]($0) })
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}
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}
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typealias UsedInputsType = (
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8
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)
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typealias EphemeralTagType = (
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8,
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UInt8
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)

‎Sources/zkp_bindings/include/Utility.h ‎Sources/zkp_bindings/include/secp256k1_swift.h

+12-1
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//
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// Utility.h
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// secp256k1_swift.h
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// GigaBitcoin/secp256k1.swift
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//
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// Copyright (c) 2021 GigaBitcoin LLC
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//
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#include "./secp256k1.h"
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#include "./secp256k1_surjectionproof.h"
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/// Exposes secp256k1 memczero implementation to the bindings target
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/// @param s pointer to an array to be zero'd by the function
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/// @param input a pointer to the data to be hashed
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/// @param len the length of the data to be hashed
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void secp256k1_swift_sha256(unsigned char *output, const unsigned char *input, size_t len);
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/// Parse a surjection proof
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/// @param data Borromean signature: e0, scalars
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/// @param proof data structure that holds a parsed surjection proof
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void secp256k1_swift_surjection_proof_parse(const unsigned char *data, secp256k1_surjectionproof proof);
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/// Serialize a surjection proof
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/// @param proof data structure that holds a parsed surjection proof
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/// @param data Borromean signature: e0, scalars
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void secp256k1_swift_surjection_proof_serialize(secp256k1_surjectionproof proof, const unsigned char *data);

‎Sources/zkp_bindings/src/Utility.c

-31
This file was deleted.

‎Sources/zkp_bindings/src/secp256k1_swift.c

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//
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// secp256k1_swift.c
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// GigaBitcoin/secp256k1.swift
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//
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// Copyright (c) 2021 GigaBitcoin LLC
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// Distributed under the MIT software license
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//
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// See the accompanying file LICENSE for information
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//
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#include "../include/secp256k1_swift.h"
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#include "../src/hash_impl.h"
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/// Exposes secp256k1 memczero implementation to the bindings target
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/// @param s pointer to an array to be zero'd by the function
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/// @param len the length of the data to be zero'd
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/// @param flag zero memory if flag == 1. Flag must be 0 or 1. Constant time.
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void secp256k1_swift_memczero(void *s, size_t len, int flag) {
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secp256k1_memczero(s, len, flag);
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}
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/// Exposes secp256k1 SHA256 implementation to the bindings target
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/// @param output pointer to an array to be filled by the function
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/// @param input a pointer to the data to be hashed
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/// @param len the length of the data to be hashed
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void secp256k1_swift_sha256(unsigned char *output, const unsigned char *input, size_t len) {
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secp256k1_sha256 hasher;
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secp256k1_sha256_initialize(&hasher);
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secp256k1_sha256_write(&hasher, input, len);
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secp256k1_sha256_finalize(&hasher, output);
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}
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/// Parse a surjection proof
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/// @param data Borromean signature: e0, scalars
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/// @param proof data structure that holds a parsed surjection proof
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void secp256k1_swift_surjection_proof_parse(const unsigned char *data, secp256k1_surjectionproof proof) {
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data = proof.data;
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}
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/// Serialize a surjection proof
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/// @param proof data structure that holds a parsed surjection proof
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/// @param data Borromean signature: e0, scalars
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void secp256k1_swift_surjection_proof_serialize(secp256k1_surjectionproof proof, const unsigned char *data) {
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memcpy(proof.data, &data, sizeof data);
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}

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