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Refactor S2K function

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This commit is contained in:
Daniel Huigens 2019-11-08 19:45:57 +01:00
parent cd2bfca519
commit 6ddfca5f14
1 changed files with 28 additions and 42 deletions
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70
src/type/s2k.js
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@ -151,55 +151,41 @@ S2K.prototype.write = function () {
*/
S2K.prototype.produce_key = async function (passphrase, numBytes) {
passphrase = util.encode_utf8(passphrase);
async function round(prefix, s2k) {
const algorithm = enums.write(enums.hash, s2k.algorithm);
switch (s2k.type) {
case 'simple':
return crypto.hash.digest(algorithm, util.concatUint8Array([prefix, passphrase]));
case 'salted':
return crypto.hash.digest(
algorithm,
util.concatUint8Array([prefix, s2k.salt, passphrase])
);
case 'iterated': {
const count = s2k.get_count();
const data = util.concatUint8Array([s2k.salt, passphrase]);
let datalen = data.length;
const prefixlen = prefix.length;
const isp = new Uint8Array(prefixlen + count);
isp.set(prefix);
isp.set(data, prefixlen);
for (let pos = prefixlen + datalen; pos < count; pos += datalen, datalen *= 2) {
isp.copyWithin(pos, prefixlen, pos);
}
return crypto.hash.digest(algorithm, isp);
}
case 'gnu':
throw new Error("GNU s2k type not supported.");
default:
throw new Error("Unknown s2k type.");
}
}
const algorithm = enums.write(enums.hash, this.algorithm);
const arr = [];
let rlength = 0;
const prefix = new Uint8Array(numBytes);
for (let i = 0; i < numBytes; i++) {
prefix[i] = 0;
}
let i = 0;
let prefixlen = 0;
while (rlength < numBytes) {
const result = await round(prefix.subarray(0, i), this);
let toHash;
switch (this.type) {
case 'simple':
toHash = util.concatUint8Array([new Uint8Array(prefixlen), passphrase]);
break;
case 'salted':
toHash = util.concatUint8Array([new Uint8Array(prefixlen), this.salt, passphrase]);
break;
case 'iterated': {
const count = this.get_count();
const data = util.concatUint8Array([this.salt, passphrase]);
let datalen = data.length;
toHash = new Uint8Array(prefixlen + count);
toHash.set(data, prefixlen);
for (let pos = prefixlen + datalen; pos < count; pos += datalen, datalen *= 2) {
toHash.copyWithin(pos, prefixlen, pos);
}
break;
}
case 'gnu':
throw new Error("GNU s2k type not supported.");
default:
throw new Error("Unknown s2k type.");
}
const result = await crypto.hash.digest(algorithm, toHash);
arr.push(result);
rlength += result.length;
i++;
prefixlen++;
}
return util.concatUint8Array(arr).subarray(0, numBytes);