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var md5 = require('create-hash/md5')
var RIPEMD160 = require('ripemd160')
var sha = require('sha.js')
var Buffer = require('safe-buffer').Buffer
var checkParameters = require('./precondition')
var defaultEncoding = require('./default-encoding')
var toBuffer = require('./to-buffer')
var ZEROS = Buffer.alloc(128)
var sizes = {
md5: 16,
sha1: 20,
sha224: 28,
sha256: 32,
sha384: 48,
sha512: 64,
rmd160: 20,
ripemd160: 20
}
function Hmac (alg, key, saltLen) {
var hash = getDigest(alg)
var blocksize = (alg === 'sha512' || alg === 'sha384') ? 128 : 64
if (key.length > blocksize) {
key = hash(key)
} else if (key.length < blocksize) {
key = Buffer.concat([key, ZEROS], blocksize)
}
var ipad = Buffer.allocUnsafe(blocksize + sizes[alg])
var opad = Buffer.allocUnsafe(blocksize + sizes[alg])
for (var i = 0; i < blocksize; i++) {
ipad[i] = key[i] ^ 0x36
opad[i] = key[i] ^ 0x5C
}
var ipad1 = Buffer.allocUnsafe(blocksize + saltLen + 4)
ipad.copy(ipad1, 0, 0, blocksize)
this.ipad1 = ipad1
this.ipad2 = ipad
this.opad = opad
this.alg = alg
this.blocksize = blocksize
this.hash = hash
this.size = sizes[alg]
}
Hmac.prototype.run = function (data, ipad) {
data.copy(ipad, this.blocksize)
var h = this.hash(ipad)
h.copy(this.opad, this.blocksize)
return this.hash(this.opad)
}
function getDigest (alg) {
function shaFunc (data) {
return sha(alg).update(data).digest()
}
function rmd160Func (data) {
return new RIPEMD160().update(data).digest()
}
if (alg === 'rmd160' || alg === 'ripemd160') return rmd160Func
if (alg === 'md5') return md5
return shaFunc
}
function pbkdf2 (password, salt, iterations, keylen, digest) {
checkParameters(iterations, keylen)
password = toBuffer(password, defaultEncoding, 'Password')
salt = toBuffer(salt, defaultEncoding, 'Salt')
digest = digest || 'sha1'
var hmac = new Hmac(digest, password, salt.length)
var DK = Buffer.allocUnsafe(keylen)
var block1 = Buffer.allocUnsafe(salt.length + 4)
salt.copy(block1, 0, 0, salt.length)
var destPos = 0
var hLen = sizes[digest]
var l = Math.ceil(keylen / hLen)
for (var i = 1; i <= l; i++) {
block1.writeUInt32BE(i, salt.length)
var T = hmac.run(block1, hmac.ipad1)
var U = T
for (var j = 1; j < iterations; j++) {
U = hmac.run(U, hmac.ipad2)
for (var k = 0; k < hLen; k++) T[k] ^= U[k]
}
T.copy(DK, destPos)
destPos += hLen
}
return DK
}
module.exports = pbkdf2