├── .travis.yml ├── LICENSE ├── README.md ├── docs └── index.md ├── index.js ├── package-lock.json ├── package.json └── tests └── index.js /.travis.yml: -------------------------------------------------------------------------------- 1 | language: node_js 2 | node_js: 3 | - "8" 4 | env: 5 | global: 6 | - CXX=g++-4.8 7 | matrix: 8 | - TEST_SUITE=test 9 | addons: 10 | apt: 11 | sources: 12 | - ubuntu-toolchain-r-test 13 | packages: 14 | - g++-4.8 15 | matrix: 16 | fast_finish: true 17 | include: 18 | - os: linux 19 | node_js: "8" 20 | env: TEST_SUITE=coveralls 21 | - os: linux 22 | node_js: "8" 23 | env: TEST_SUITE=lint 24 | script: npm run $TEST_SUITE 25 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Mozilla Public License Version 2.0 2 | ================================== 3 | 4 | 1. Definitions 5 | -------------- 6 | 7 | 1.1. "Contributor" 8 | means each individual or legal entity that creates, contributes to 9 | the creation of, or owns Covered Software. 10 | 11 | 1.2. "Contributor Version" 12 | means the combination of the Contributions of others (if any) used 13 | by a Contributor and that particular Contributor's Contribution. 14 | 15 | 1.3. "Contribution" 16 | means Covered Software of a particular Contributor. 17 | 18 | 1.4. "Covered Software" 19 | means Source Code Form to which the initial Contributor has attached 20 | the notice in Exhibit A, the Executable Form of such Source Code 21 | Form, and Modifications of such Source Code Form, in each case 22 | including portions thereof. 23 | 24 | 1.5. "Incompatible With Secondary Licenses" 25 | means 26 | 27 | (a) that the initial Contributor has attached the notice described 28 | in Exhibit B to the Covered Software; or 29 | 30 | (b) that the Covered Software was made available under the terms of 31 | version 1.1 or earlier of the License, but not also under the 32 | terms of a Secondary License. 33 | 34 | 1.6. "Executable Form" 35 | means any form of the work other than Source Code Form. 36 | 37 | 1.7. "Larger Work" 38 | means a work that combines Covered Software with other material, in 39 | a separate file or files, that is not Covered Software. 40 | 41 | 1.8. "License" 42 | means this document. 43 | 44 | 1.9. "Licensable" 45 | means having the right to grant, to the maximum extent possible, 46 | whether at the time of the initial grant or subsequently, any and 47 | all of the rights conveyed by this License. 48 | 49 | 1.10. "Modifications" 50 | means any of the following: 51 | 52 | (a) any file in Source Code Form that results from an addition to, 53 | deletion from, or modification of the contents of Covered 54 | Software; or 55 | 56 | (b) any new file in Source Code Form that contains any Covered 57 | Software. 58 | 59 | 1.11. "Patent Claims" of a Contributor 60 | means any patent claim(s), including without limitation, method, 61 | process, and apparatus claims, in any patent Licensable by such 62 | Contributor that would be infringed, but for the grant of the 63 | License, by the making, using, selling, offering for sale, having 64 | made, import, or transfer of either its Contributions or its 65 | Contributor Version. 66 | 67 | 1.12. "Secondary License" 68 | means either the GNU General Public License, Version 2.0, the GNU 69 | Lesser General Public License, Version 2.1, the GNU Affero General 70 | Public License, Version 3.0, or any later versions of those 71 | licenses. 72 | 73 | 1.13. "Source Code Form" 74 | means the form of the work preferred for making modifications. 75 | 76 | 1.14. "You" (or "Your") 77 | means an individual or a legal entity exercising rights under this 78 | License. For legal entities, "You" includes any entity that 79 | controls, is controlled by, or is under common control with You. For 80 | purposes of this definition, "control" means (a) the power, direct 81 | or indirect, to cause the direction or management of such entity, 82 | whether by contract or otherwise, or (b) ownership of more than 83 | fifty percent (50%) of the outstanding shares or beneficial 84 | ownership of such entity. 85 | 86 | 2. License Grants and Conditions 87 | -------------------------------- 88 | 89 | 2.1. Grants 90 | 91 | Each Contributor hereby grants You a world-wide, royalty-free, 92 | non-exclusive license: 93 | 94 | (a) under intellectual property rights (other than patent or trademark) 95 | Licensable by such Contributor to use, reproduce, make available, 96 | modify, display, perform, distribute, and otherwise exploit its 97 | Contributions, either on an unmodified basis, with Modifications, or 98 | as part of a Larger Work; and 99 | 100 | (b) under Patent Claims of such Contributor to make, use, sell, offer 101 | for sale, have made, import, and otherwise transfer either its 102 | Contributions or its Contributor Version. 103 | 104 | 2.2. Effective Date 105 | 106 | The licenses granted in Section 2.1 with respect to any Contribution 107 | become effective for each Contribution on the date the Contributor first 108 | distributes such Contribution. 109 | 110 | 2.3. Limitations on Grant Scope 111 | 112 | The licenses granted in this Section 2 are the only rights granted under 113 | this License. No additional rights or licenses will be implied from the 114 | distribution or licensing of Covered Software under this License. 115 | Notwithstanding Section 2.1(b) above, no patent license is granted by a 116 | Contributor: 117 | 118 | (a) for any code that a Contributor has removed from Covered Software; 119 | or 120 | 121 | (b) for infringements caused by: (i) Your and any other third party's 122 | modifications of Covered Software, or (ii) the combination of its 123 | Contributions with other software (except as part of its Contributor 124 | Version); or 125 | 126 | (c) under Patent Claims infringed by Covered Software in the absence of 127 | its Contributions. 128 | 129 | This License does not grant any rights in the trademarks, service marks, 130 | or logos of any Contributor (except as may be necessary to comply with 131 | the notice requirements in Section 3.4). 132 | 133 | 2.4. Subsequent Licenses 134 | 135 | No Contributor makes additional grants as a result of Your choice to 136 | distribute the Covered Software under a subsequent version of this 137 | License (see Section 10.2) or under the terms of a Secondary License (if 138 | permitted under the terms of Section 3.3). 139 | 140 | 2.5. Representation 141 | 142 | Each Contributor represents that the Contributor believes its 143 | Contributions are its original creation(s) or it has sufficient rights 144 | to grant the rights to its Contributions conveyed by this License. 145 | 146 | 2.6. Fair Use 147 | 148 | This License is not intended to limit any rights You have under 149 | applicable copyright doctrines of fair use, fair dealing, or other 150 | equivalents. 151 | 152 | 2.7. Conditions 153 | 154 | Sections 3.1, 3.2, 3.3, and 3.4 are conditions of the licenses granted 155 | in Section 2.1. 156 | 157 | 3. Responsibilities 158 | ------------------- 159 | 160 | 3.1. Distribution of Source Form 161 | 162 | All distribution of Covered Software in Source Code Form, including any 163 | Modifications that You create or to which You contribute, must be under 164 | the terms of this License. You must inform recipients that the Source 165 | Code Form of the Covered Software is governed by the terms of this 166 | License, and how they can obtain a copy of this License. You may not 167 | attempt to alter or restrict the recipients' rights in the Source Code 168 | Form. 169 | 170 | 3.2. Distribution of Executable Form 171 | 172 | If You distribute Covered Software in Executable Form then: 173 | 174 | (a) such Covered Software must also be made available in Source Code 175 | Form, as described in Section 3.1, and You must inform recipients of 176 | the Executable Form how they can obtain a copy of such Source Code 177 | Form by reasonable means in a timely manner, at a charge no more 178 | than the cost of distribution to the recipient; and 179 | 180 | (b) You may distribute such Executable Form under the terms of this 181 | License, or sublicense it under different terms, provided that the 182 | license for the Executable Form does not attempt to limit or alter 183 | the recipients' rights in the Source Code Form under this License. 184 | 185 | 3.3. Distribution of a Larger Work 186 | 187 | You may create and distribute a Larger Work under terms of Your choice, 188 | provided that You also comply with the requirements of this License for 189 | the Covered Software. If the Larger Work is a combination of Covered 190 | Software with a work governed by one or more Secondary Licenses, and the 191 | Covered Software is not Incompatible With Secondary Licenses, this 192 | License permits You to additionally distribute such Covered Software 193 | under the terms of such Secondary License(s), so that the recipient of 194 | the Larger Work may, at their option, further distribute the Covered 195 | Software under the terms of either this License or such Secondary 196 | License(s). 197 | 198 | 3.4. Notices 199 | 200 | You may not remove or alter the substance of any license notices 201 | (including copyright notices, patent notices, disclaimers of warranty, 202 | or limitations of liability) contained within the Source Code Form of 203 | the Covered Software, except that You may alter any license notices to 204 | the extent required to remedy known factual inaccuracies. 205 | 206 | 3.5. Application of Additional Terms 207 | 208 | You may choose to offer, and to charge a fee for, warranty, support, 209 | indemnity or liability obligations to one or more recipients of Covered 210 | Software. However, You may do so only on Your own behalf, and not on 211 | behalf of any Contributor. You must make it absolutely clear that any 212 | such warranty, support, indemnity, or liability obligation is offered by 213 | You alone, and You hereby agree to indemnify every Contributor for any 214 | liability incurred by such Contributor as a result of warranty, support, 215 | indemnity or liability terms You offer. You may include additional 216 | disclaimers of warranty and limitations of liability specific to any 217 | jurisdiction. 218 | 219 | 4. Inability to Comply Due to Statute or Regulation 220 | --------------------------------------------------- 221 | 222 | If it is impossible for You to comply with any of the terms of this 223 | License with respect to some or all of the Covered Software due to 224 | statute, judicial order, or regulation then You must: (a) comply with 225 | the terms of this License to the maximum extent possible; and (b) 226 | describe the limitations and the code they affect. Such description must 227 | be placed in a text file included with all distributions of the Covered 228 | Software under this License. Except to the extent prohibited by statute 229 | or regulation, such description must be sufficiently detailed for a 230 | recipient of ordinary skill to be able to understand it. 231 | 232 | 5. Termination 233 | -------------- 234 | 235 | 5.1. The rights granted under this License will terminate automatically 236 | if You fail to comply with any of its terms. However, if You become 237 | compliant, then the rights granted under this License from a particular 238 | Contributor are reinstated (a) provisionally, unless and until such 239 | Contributor explicitly and finally terminates Your grants, and (b) on an 240 | ongoing basis, if such Contributor fails to notify You of the 241 | non-compliance by some reasonable means prior to 60 days after You have 242 | come back into compliance. Moreover, Your grants from a particular 243 | Contributor are reinstated on an ongoing basis if such Contributor 244 | notifies You of the non-compliance by some reasonable means, this is the 245 | first time You have received notice of non-compliance with this License 246 | from such Contributor, and You become compliant prior to 30 days after 247 | Your receipt of the notice. 248 | 249 | 5.2. If You initiate litigation against any entity by asserting a patent 250 | infringement claim (excluding declaratory judgment actions, 251 | counter-claims, and cross-claims) alleging that a Contributor Version 252 | directly or indirectly infringes any patent, then the rights granted to 253 | You by any and all Contributors for the Covered Software under Section 254 | 2.1 of this License shall terminate. 255 | 256 | 5.3. In the event of termination under Sections 5.1 or 5.2 above, all 257 | end user license agreements (excluding distributors and resellers) which 258 | have been validly granted by You or Your distributors under this License 259 | prior to termination shall survive termination. 260 | 261 | ************************************************************************ 262 | * * 263 | * 6. Disclaimer of Warranty * 264 | * ------------------------- * 265 | * * 266 | * Covered Software is provided under this License on an "as is" * 267 | * basis, without warranty of any kind, either expressed, implied, or * 268 | * statutory, including, without limitation, warranties that the * 269 | * Covered Software is free of defects, merchantable, fit for a * 270 | * particular purpose or non-infringing. The entire risk as to the * 271 | * quality and performance of the Covered Software is with You. * 272 | * Should any Covered Software prove defective in any respect, You * 273 | * (not any Contributor) assume the cost of any necessary servicing, * 274 | * repair, or correction. This disclaimer of warranty constitutes an * 275 | * essential part of this License. No use of any Covered Software is * 276 | * authorized under this License except under this disclaimer. * 277 | * * 278 | ************************************************************************ 279 | 280 | ************************************************************************ 281 | * * 282 | * 7. Limitation of Liability * 283 | * -------------------------- * 284 | * * 285 | * Under no circumstances and under no legal theory, whether tort * 286 | * (including negligence), contract, or otherwise, shall any * 287 | * Contributor, or anyone who distributes Covered Software as * 288 | * permitted above, be liable to You for any direct, indirect, * 289 | * special, incidental, or consequential damages of any character * 290 | * including, without limitation, damages for lost profits, loss of * 291 | * goodwill, work stoppage, computer failure or malfunction, or any * 292 | * and all other commercial damages or losses, even if such party * 293 | * shall have been informed of the possibility of such damages. This * 294 | * limitation of liability shall not apply to liability for death or * 295 | * personal injury resulting from such party's negligence to the * 296 | * extent applicable law prohibits such limitation. Some * 297 | * jurisdictions do not allow the exclusion or limitation of * 298 | * incidental or consequential damages, so this exclusion and * 299 | * limitation may not apply to You. * 300 | * * 301 | ************************************************************************ 302 | 303 | 8. Litigation 304 | ------------- 305 | 306 | Any litigation relating to this License may be brought only in the 307 | courts of a jurisdiction where the defendant maintains its principal 308 | place of business and such litigation shall be governed by laws of that 309 | jurisdiction, without reference to its conflict-of-law provisions. 310 | Nothing in this Section shall prevent a party's ability to bring 311 | cross-claims or counter-claims. 312 | 313 | 9. Miscellaneous 314 | ---------------- 315 | 316 | This License represents the complete agreement concerning the subject 317 | matter hereof. If any provision of this License is held to be 318 | unenforceable, such provision shall be reformed only to the extent 319 | necessary to make it enforceable. Any law or regulation which provides 320 | that the language of a contract shall be construed against the drafter 321 | shall not be used to construe this License against a Contributor. 322 | 323 | 10. Versions of the License 324 | --------------------------- 325 | 326 | 10.1. New Versions 327 | 328 | Mozilla Foundation is the license steward. Except as provided in Section 329 | 10.3, no one other than the license steward has the right to modify or 330 | publish new versions of this License. Each version will be given a 331 | distinguishing version number. 332 | 333 | 10.2. Effect of New Versions 334 | 335 | You may distribute the Covered Software under the terms of the version 336 | of the License under which You originally received the Covered Software, 337 | or under the terms of any subsequent version published by the license 338 | steward. 339 | 340 | 10.3. Modified Versions 341 | 342 | If you create software not governed by this License, and you want to 343 | create a new license for such software, you may create and use a 344 | modified version of this License if you rename the license and remove 345 | any references to the name of the license steward (except to note that 346 | such modified license differs from this License). 347 | 348 | 10.4. Distributing Source Code Form that is Incompatible With Secondary 349 | Licenses 350 | 351 | If You choose to distribute Source Code Form that is Incompatible With 352 | Secondary Licenses under the terms of this version of the License, the 353 | notice described in Exhibit B of this License must be attached. 354 | 355 | Exhibit A - Source Code Form License Notice 356 | ------------------------------------------- 357 | 358 | This Source Code Form is subject to the terms of the Mozilla Public 359 | License, v. 2.0. If a copy of the MPL was not distributed with this 360 | file, You can obtain one at http://mozilla.org/MPL/2.0/. 361 | 362 | If it is not possible or desirable to put the notice in a particular 363 | file, then You may include the notice in a location (such as a LICENSE 364 | file in a relevant directory) where a recipient would be likely to look 365 | for such a notice. 366 | 367 | You may add additional accurate notices of copyright ownership. 368 | 369 | Exhibit B - "Incompatible With Secondary Licenses" Notice 370 | --------------------------------------------------------- 371 | 372 | This Source Code Form is "Incompatible With Secondary Licenses", as 373 | defined by the Mozilla Public License, v. 2.0. 374 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # SYNOPSIS 2 | [![Build Status](https://img.shields.io/travis/wanderer/vss.svg?branch=master&style=flat-square)](https://travis-ci.org/wanderer/vss) 3 | [![Coverage Status](https://img.shields.io/coveralls/wanderer/vss.svg?style=flat-square)](https://coveralls.io/r/wanderer/vss) 4 | 5 | [![js-standard-style](https://cdn.rawgit.com/feross/standard/master/badge.svg)](https://github.com/feross/standard) 6 | 7 | This implements [verifiable secret sharing](https://en.wikipedia.org/wiki/Verifiable_secret_sharing) on top of [bls-lib](https://github.com/wanderer/bls-lib/). 8 | Its is based on [Shamir's scheme](https://en.wikipedia.org/wiki/Secret_sharing#Shamir.27s_scheme) but has the added benefit that ths recipients can verify their shares against a verifcation vector. 9 | This insures that dealer cannot hand out invalid shares. 10 | 11 | # INSTALL 12 | `npm install vss` 13 | 14 | # USAGE 15 | 16 | ```javascript 17 | const vss = require('vss') 18 | const bls = require('bls-lib') 19 | 20 | bls.onModuleInit(() => { 21 | bls.init() 22 | const threshold = 5 23 | const numOfPlayers = 7 24 | const setup = vss.createShare(bls, numOfPlayers, threshold) 25 | 26 | // use `setup.secret` to encrypt something, it is a random 32 byte Uint8Array 27 | // post `setup.verificationVector` somewhere public 28 | // then send each share in `setup.shares` to someone 29 | 30 | // when the recipients recieve thier share they can verify that it was created 31 | // corectly with the verifcationVector 32 | setup.shares.forEach(share => { 33 | const verified = vss.verifyShare(bls, share, setup.verifcationVector) 34 | console.log(verified) 35 | }) 36 | 37 | // when `threshold` number of recipients combine their shares the secert key 38 | // can be recovered 39 | const secret = vss.recoverSecret(bls, setup.shares.slice(0, threshold)) 40 | // secret === setup.secret 41 | }) 42 | ``` 43 | 44 | # API 45 | [./docs/](./docs/index.md) 46 | 47 | # LICENSE 48 | [MPL-2.0](https://tldrlegal.com/license/mozilla-public-license-2.0-(mpl-2)) 49 | -------------------------------------------------------------------------------- /docs/index.md: -------------------------------------------------------------------------------- 1 | 2 | 3 | ### Table of Contents 4 | 5 | - [createShare][1] 6 | - [Parameters][2] 7 | - [renewShare][3] 8 | - [Parameters][4] 9 | - [verifyShare][5] 10 | - [Parameters][6] 11 | - [recoverSecret][7] 12 | - [Parameters][8] 13 | 14 | ## createShare 15 | 16 | [index.js:9-49][9] 17 | 18 | creates a secert to share, an array of shares to share and a verifaction vector 19 | 20 | ### Parameters 21 | 22 | - `bls` **[Object][10]** an instance of [bls-lib][11] 23 | - `numOfShares` **[Number][12]** the number of share to create 24 | - `threshold` **[Number][12]** the number of share needed to recover the secret 25 | 26 | Returns **[Object][10]** the return value contains `verifcationVector`, and array of `shares` and a random `secert` 27 | 28 | ## renewShare 29 | 30 | [index.js:58-119][13] 31 | 32 | renew shares and verification vector, while keeping the secret 33 | 34 | ### Parameters 35 | 36 | - `bls` **[Object][10]** an instance of [bls-lib][11] 37 | - `shares` **[Number][12]** the array of shares to be renewed (it is not possible to renew only some shares ; all must be). This array will not be modified, and new shares appear in the return object. 38 | - `threshold` **[Number][12]** the number of share needed to recover the secret 39 | - `oldVvec` 40 | 41 | Returns **[Object][10]** the return value contains the new `verifcationVector`, an array containing the new `shares`, and the `secret` (which has not changed in respect to the original shares) 42 | 43 | ## verifyShare 44 | 45 | [index.js:128-148][14] 46 | 47 | verifys a share again a verifcation vector 48 | 49 | ### Parameters 50 | 51 | - `bls` **[Object][10]** an instance of [bls-lib][11] 52 | - `share` **[Object][10]** a share 53 | - `vvec` **[Array][15]** the verifcation vector 54 | 55 | Returns **[Boolean][16]** 56 | 57 | ## recoverSecret 58 | 59 | [index.js:155-166][17] 60 | 61 | verifys a share again a verifcation vector 62 | 63 | ### Parameters 64 | 65 | - `bls` 66 | - `shares` **[Array][15]** an array of unque shares containing threshold number of shares 67 | 68 | Returns **[Uint8Array][18]** the recovered secret 69 | 70 | [1]: #createshare 71 | 72 | [2]: #parameters 73 | 74 | [3]: #renewshare 75 | 76 | [4]: #parameters-1 77 | 78 | [5]: #verifyshare 79 | 80 | [6]: #parameters-2 81 | 82 | [7]: #recoversecret 83 | 84 | [8]: #parameters-3 85 | 86 | [9]: https://github.com/wanderer/vss/blob/353905bd7a0d60a7ca7155c05f3fe9c5b5e4d176/index.js#L9-L49 "Source code on GitHub" 87 | 88 | [10]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Object 89 | 90 | [11]: https://github.com/wanderer/bls-lib 91 | 92 | [12]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Number 93 | 94 | [13]: https://github.com/wanderer/vss/blob/353905bd7a0d60a7ca7155c05f3fe9c5b5e4d176/index.js#L58-L119 "Source code on GitHub" 95 | 96 | [14]: https://github.com/wanderer/vss/blob/353905bd7a0d60a7ca7155c05f3fe9c5b5e4d176/index.js#L128-L148 "Source code on GitHub" 97 | 98 | [15]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Array 99 | 100 | [16]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Boolean 101 | 102 | [17]: https://github.com/wanderer/vss/blob/353905bd7a0d60a7ca7155c05f3fe9c5b5e4d176/index.js#L155-L166 "Source code on GitHub" 103 | 104 | [18]: https://developer.mozilla.org/docs/Web/JavaScript/Reference/Global_Objects/Uint8Array 105 | -------------------------------------------------------------------------------- /index.js: -------------------------------------------------------------------------------- 1 | 2 | /** 3 | * creates a secert to share, an array of shares to share and a verifaction vector 4 | * @param {Object} bls - an instance of [bls-lib](https://github.com/wanderer/bls-lib) 5 | * @param {Number} numOfShares - the number of share to create 6 | * @param {Number} threshold - the number of share needed to recover the secret 7 | * @returns {Object} the return value contains `verifcationVector`, and array of `shares` and a random `secert` 8 | */ 9 | exports.createShare = function (bls, numOfShares, threshold) { 10 | // import secret 11 | // generate a sk and vvec 12 | const svec = [] 13 | const vvec = [] 14 | const shares = [] 15 | for (let i = 0; i < threshold; i++) { 16 | const sk = bls.secretKey() 17 | bls.secretKeySetByCSPRNG(sk) 18 | svec.push(sk) 19 | 20 | const pk = bls.publicKey() 21 | bls.getPublicKey(pk, sk) 22 | vvec.push(pk) 23 | } 24 | 25 | // generate key shares 26 | for (let i = 1; i < numOfShares + 1; i++) { 27 | const sk = bls.secretKey() 28 | const id = bls.idImportFromInt(i) 29 | bls.secretKeyShare(sk, svec, id) 30 | shares.push({ 31 | sk: bls.secretKeyExport(sk), 32 | id: i 33 | }) 34 | bls.free(id) 35 | bls.free(sk) 36 | } 37 | 38 | const results = { 39 | verifcationVector: vvec.map(pk => bls.publicKeyExport(pk)), 40 | shares: shares, 41 | secret: bls.secretKeyExport(svec[0]) 42 | } 43 | 44 | // clean up! 45 | bls.freeArray(vvec) 46 | bls.freeArray(svec) 47 | 48 | return results 49 | } 50 | 51 | /** 52 | * renew shares and verification vector, while keeping the secret 53 | * @param {Object} bls - an instance of [bls-lib](https://github.com/wanderer/bls-lib) 54 | * @param {Number} shares - the array of shares to be renewed (it is not possible to renew only some shares ; all must be). This array will not be modified, and new shares appear in the return object. 55 | * @param {Number} threshold - the number of share needed to recover the secret 56 | * @returns {Object} the return value contains the new `verifcationVector`, an array containing the new `shares`, and the `secret` (which has not changed in respect to the original shares) 57 | */ 58 | exports.renewShare = function (bls, shares, threshold, oldVvec) { 59 | // import secret 60 | // generate a sk and vvec 61 | const svec = [] 62 | const vvec = [] 63 | 64 | const zeroArray = Buffer.alloc(32) 65 | const zeroSK = bls.secretKeyImport(zeroArray) 66 | svec.push(zeroSK) 67 | 68 | const zeroPK = bls.publicKey() 69 | bls.getPublicKey(zeroPK, zeroSK) 70 | vvec.push(zeroPK) 71 | 72 | for (let i = 1; i < threshold; i++) { 73 | const sk = bls.secretKey() 74 | bls.secretKeySetByCSPRNG(sk) 75 | svec.push(sk) 76 | 77 | const pk = bls.publicKey() 78 | bls.getPublicKey(pk, sk) 79 | vvec.push(pk) 80 | } 81 | 82 | // generate key shares 83 | const newShares = [] 84 | shares.forEach(share => { 85 | var sk = bls.secretKey() 86 | const id = bls.idImportFromInt(share.id) 87 | bls.secretKeyShare(sk, svec, id) 88 | 89 | const originalShare = bls.secretKeyImport(share.sk) 90 | bls.secretKeyAdd(sk, originalShare) 91 | bls.free(originalShare) 92 | 93 | newShares.push({ 94 | sk: bls.secretKeyExport(sk), 95 | id: share.id 96 | }) 97 | bls.free(id) 98 | bls.free(sk) 99 | }) 100 | 101 | const newVvec = oldVvec.map((pk, i) => { 102 | pk = bls.publicKeyImport(pk) 103 | bls.publicKeyAdd(pk, vvec[i]) 104 | return pk 105 | }) 106 | 107 | const results = { 108 | verifcationVector: newVvec.map(pk => bls.publicKeyExport(pk)), 109 | shares: newShares, 110 | secret: bls.secretKeyExport(svec[0]) 111 | } 112 | 113 | // clean up! 114 | bls.freeArray(vvec) 115 | bls.freeArray(newVvec) 116 | bls.freeArray(svec) 117 | 118 | return results 119 | } 120 | 121 | /** 122 | * verifys a share again a verifcation vector 123 | * @param {Object} bls - an instance of [bls-lib](https://github.com/wanderer/bls-lib) 124 | * @param {Object} share - a share 125 | * @param {Array} vvec - the verifcation vector 126 | * @return {Boolean} 127 | */ 128 | exports.verifyShare = function (bls, share, vvec) { 129 | const pk1 = bls.publicKey() 130 | const sk = bls.secretKeyImport(share.sk) 131 | 132 | vvec = vvec.map(pk => bls.publicKeyImport(pk)) 133 | 134 | const id = bls.idImportFromInt(share.id) 135 | bls.publicKeyShare(pk1, vvec, id) 136 | 137 | const pk2 = bls.publicKey() 138 | bls.getPublicKey(pk2, sk) 139 | 140 | const isEqual = bls.publicKeyIsEqual(pk1, pk2) 141 | 142 | bls.freeArray(vvec) 143 | bls.free(pk1) 144 | bls.free(pk2) 145 | bls.free(id) 146 | 147 | return Boolean(isEqual) 148 | } 149 | 150 | /** 151 | * verifys a share again a verifcation vector 152 | * @param {Array} shares - an array of unque shares containing threshold number of shares 153 | * @returns {Uint8Array} - the recovered secret 154 | */ 155 | exports.recoverSecret = function (bls, shares) { 156 | const sk = bls.secretKey() 157 | const sks = shares.map(s => bls.secretKeyImport(s.sk)) 158 | const ids = shares.map(s => bls.idImportFromInt(s.id)) 159 | bls.secretKeyRecover(sk, sks, ids) 160 | const result = bls.secretKeyExport(sk) 161 | 162 | bls.free(sk) 163 | bls.freeArray(sks) 164 | bls.freeArray(ids) 165 | return result 166 | } 167 | -------------------------------------------------------------------------------- /package.json: -------------------------------------------------------------------------------- 1 | { 2 | "name": "vss", 3 | "version": "0.1.0", 4 | "description": "this implements verifiable secret sharing", 5 | "main": "index.js", 6 | "scripts": { 7 | "coveralls": "npm run coverage && nyc report --reporter=text-lcov | coveralls", 8 | "coverage": "nyc npm test", 9 | "lint": "standard", 10 | "test": "node ./tests/index.js", 11 | "build:docs": "documentation build --github -f md ./index.js > ./docs/index.md" 12 | }, 13 | "keywords": [ 14 | "crypto", 15 | "vss" 16 | ], 17 | "author": "mjbecze ", 18 | "license": "MPL-2.0", 19 | "dependencies": {}, 20 | "devDependencies": { 21 | "bls-lib": "^0.3.0", 22 | "coveralls": "^3.0.2", 23 | "documentation": "^9.0.0", 24 | "istanbul": "^0.4.1", 25 | "nyc": "^13.1.0", 26 | "standard": "^12.0.1", 27 | "tape": "^4.9.1" 28 | }, 29 | "repository": { 30 | "type": "git", 31 | "url": "git@github.com:wanderer/vss.git" 32 | }, 33 | "bugs": { 34 | "url": "https://github.com/wanderer/vss/issues" 35 | }, 36 | "homepage": "https://github.com/wanderer/vss" 37 | } 38 | -------------------------------------------------------------------------------- /tests/index.js: -------------------------------------------------------------------------------- 1 | const tape = require('tape') 2 | const vss = require('../') 3 | const bls = require('bls-lib') 4 | 5 | bls.onModuleInit(() => { 6 | tape('tests', (t) => { 7 | bls.init() 8 | 9 | const threshold = 4 10 | const numOfPlayers = 7 11 | const setup = vss.createShare(bls, numOfPlayers, threshold) 12 | 13 | setup.shares.forEach(share => { 14 | const verified = vss.verifyShare(bls, share, setup.verifcationVector) 15 | t.true(verified, 'should verify share') 16 | }) 17 | 18 | var secret = vss.recoverSecret(bls, setup.shares.slice(0, threshold)) 19 | t.deepEqual(secret, setup.secret, 'should recover the secret') 20 | 21 | const renewal = vss.renewShare(bls, setup.shares, threshold, setup.verifcationVector) 22 | 23 | renewal.shares.forEach(share => { 24 | const verified = vss.verifyShare(bls, share, renewal.verifcationVector) 25 | t.true(verified, 'should verify new share') 26 | }) 27 | 28 | secret = vss.recoverSecret(bls, renewal.shares.slice(0, threshold)) 29 | t.deepEqual(secret, setup.secret, 'secret should not change after share renewal') 30 | 31 | t.end() 32 | }) 33 | }) 34 | --------------------------------------------------------------------------------