Dr. Mark B. Lundeberg, 2018 August 30
bitcoincash:qqy9myvyt7qffgye5a2mn2vn8ry95qm6asy40ptgx2
Since version 2.1, GnuPG is able to use the very same secp256k1 elliptic curve signature algorithm (ECDSA) as used in bitcoin. Quite soon Bitcoin Cash will add a new script opcode OP_CHECKDATASIG that is able to check signatures not just on the containing transaction, but also on arbitrary data. For fun, let's try to intersect the two signature systems and see what can be done!
| const readline = require('readline'); | |
| const rl = readline.createInterface({ | |
| input: process.stdin, | |
| output: process.stdout | |
| }); | |
| let stack = []; | |
| let consts = { | |
| swapd: '[[swap] dip]', | |
| popd: '[[pop] dip]', |
| // used to retrieve template content | |
| const templates = new WeakMap; | |
| // used to retrieve node updates | |
| const updates = new WeakMap; | |
| // hyperHTML, the nitty gritty | |
| function hyperHTML(chunks, ...interpolations) { | |
| // if the static chunks are unknown |
| /* eslint no-param-reassign: 0 */ | |
| /** | |
| * JavaScript implementation of W3 DOM4 TreeWalker interface. | |
| * | |
| * See also: | |
| * - https://dom.spec.whatwg.org/#interface-treewalker | |
| * | |
| * Attributes like "read-only" and "private" are ignored in this implementation | |
| * due to ECMAScript 3 (as opposed to ES5) not supporting creation of such properties. |
| const nodes = [ | |
| { | |
| links: [ 1 ], // node 0 is linked to node 1 | |
| visited: false | |
| }, { | |
| links: [ 0, 2 ], // node 1 is linked to node 0 and 2 | |
| visited: false | |
| }, | |
| ... | |
| ]; |
| // General hints on defining types with constraints or invariants | |
| // | |
| // Just as in C#, use a private constructor | |
| // and expose "factory" methods that enforce the constraints | |
| // | |
| // In F#, only classes can have private constructors with public members. | |
| // | |
| // If you want to use the record and DU types, the whole type becomes | |
| // private, which means that you also need to provide: | |
| // * a constructor function ("create"). |
| // This works on all devices/browsers, and uses IndexedDBShim as a final fallback | |
| var indexedDB = window.indexedDB || window.mozIndexedDB || window.webkitIndexedDB || window.msIndexedDB || window.shimIndexedDB; | |
| // Open (or create) the database | |
| var open = indexedDB.open("MyDatabase", 1); | |
| // Create the schema | |
| open.onupgradeneeded = function() { | |
| var db = open.result; | |
| var store = db.createObjectStore("MyObjectStore", {keyPath: "id"}); |
| @In((a: string, b: string) => { | |
| assert(typeof a === 'string'); | |
| assert(typeof b === 'string'); | |
| assert(a.length > 5); | |
| assert(a.length > 7); | |
| }) | |
| @Out((result: string) => { | |
| assert(typeof result === 'string'); | |
| assert(a.length > 12); | |
| }) |
