livecodingspace-app/public/lib/gundb/sea/verify.js

    var SEA = require('./root');
    var shim = require('./shim');
    var S = require('./settings');
    var sha256hash = require('./sha256');
    var parse = require('./parse');
    var u;

    SEA.verify = async (data, pair, cb) => { try {
      const json = parse(data)
      if(false === pair){ // don't verify!
        const raw = (json !== data)? 
          (json.s && json.m)? parse(json.m) : data
        : json;
        if(cb){ try{ cb(raw) }catch(e){console.log(e)} }
        return raw;
      }
      const pub = pair.pub || pair
      const jwk = S.jwk(pub)
      const key = await (shim.ossl || shim.subtle).importKey('jwk', jwk, S.ecdsa.pair, false, ['verify'])
      const hash = await sha256hash(json.m)
      const sig = new Uint8Array(shim.Buffer.from(json.s, 'utf8'))
      const check = await (shim.ossl || shim.subtle).verify(S.ecdsa.sign, key, sig, new Uint8Array(hash))
      if(!check){ throw "Signature did not match." }
      const r = check? parse(json.m) : u;

      if(cb){ try{ cb(r) }catch(e){console.log(e)} }
      return r;
    } catch(e) {
      console.log(e);
      SEA.err = e;
      if(cb){ cb() }
      return;
    }}

    module.exports = SEA.verify;