linux password sha512 encrypt with nodejs

linux-password-crypt-sha512.js

const crypto = require('crypto')

const SALT_LEN_MAX = 16
const DEFAULT_ROUNDS = 5000

function sha512crypt(key, salt) {
  salt = salt.slice(0, SALT_LEN_MAX)

  let cnt = 0

  // step 1-3
  const hashA = crypto.createHash('sha512')
  hashA.update(key)
  hashA.update(salt)

  // step 4-8
  const hashB = crypto.createHash('sha512')
  hashB.update(key)
  hashB.update(salt)
  hashB.update(key)
  let altResult = hashB.digest()

  // step: 9-10
  for (cnt = key.length; cnt > 64; cnt -= 64) {
    hashA.update(altResult)
  }
  hashA.update(altResult.slice(0, cnt))

  // setp: 11-12
  for (cnt = key.length; cnt > 0; cnt >>= 1) {
    if ((cnt & 1) != 0) {
      hashA.update(altResult)
    } else {
      hashA.update(key)
    }
  }
  altResult = hashA.digest()

  // step: 13-15
  const hashDP = crypto.createHash('sha512')
  for (cnt = 0; cnt < key.length; cnt++) {
    hashDP.update(password)
  }
  let tempResult = hashDP.digest()

  // step: 16
  let P = Buffer.from('')
  for (cnt = key.length; cnt > 64; cnt -= 64) {
    P = Buffer.concat([P, tempResult])
  }
  P = Buffer.concat([P, tempResult.slice(0, cnt)])

  // step: 17-19
  const hashDS = crypto.createHash('sha512')
  for (cnt = 0; cnt < 16 + altResult[0]; ++cnt) hashDS.update(salt)

  tempResult = hashDS.digest()

  // step: 20
  let S = Buffer.from('')
  for (cnt = salt.length; cnt >= 64; cnt -= 64) {
    S = Buffer.concat([S, tempResult])
  }
  S = Buffer.concat([S, tempResult.slice(0, cnt)])

  // step: 21
  for (cnt = 0; cnt < DEFAULT_ROUNDS; ++cnt) {
    const hashC = crypto.createHash('sha512')
    if ((cnt & 1) != 0) {
      hashC.update(P.slice(0, key.length))
    } else {
      hashC.update(altResult)
    }

    if (cnt % 3 != 0) {
      hashC.update(S.slice(0, salt.length))
    }

    if (cnt % 7 != 0) {
      hashC.update(P.slice(0, key.length))
    }

    if ((cnt & 1) != 0) {
      hashC.update(altResult)
    } else {
      hashC.update(P.slice(0, key.length))
    }

    altResult = hashC.digest()
  }

  // step: 22
  const result = [
    radix64(Buffer.from([altResult[0], altResult[21], altResult[42]])),
    radix64(Buffer.from([altResult[22], altResult[43], altResult[1]])),
    radix64(Buffer.from([altResult[44], altResult[2], altResult[23]])),
    radix64(Buffer.from([altResult[3], altResult[24], altResult[45]])),
    radix64(Buffer.from([altResult[25], altResult[46], altResult[4]])),
    radix64(Buffer.from([altResult[47], altResult[5], altResult[26]])),
    radix64(Buffer.from([altResult[6], altResult[27], altResult[48]])),
    radix64(Buffer.from([altResult[28], altResult[49], altResult[7]])),
    radix64(Buffer.from([altResult[50], altResult[8], altResult[29]])),
    radix64(Buffer.from([altResult[9], altResult[30], altResult[51]])),
    radix64(Buffer.from([altResult[31], altResult[52], altResult[10]])),
    radix64(Buffer.from([altResult[53], altResult[11], altResult[32]])),
    radix64(Buffer.from([altResult[12], altResult[33], altResult[54]])),
    radix64(Buffer.from([altResult[34], altResult[55], altResult[13]])),
    radix64(Buffer.from([altResult[56], altResult[14], altResult[35]])),
    radix64(Buffer.from([altResult[15], altResult[36], altResult[57]])),
    radix64(Buffer.from([altResult[37], altResult[58], altResult[16]])),
    radix64(Buffer.from([altResult[59], altResult[17], altResult[38]])),
    radix64(Buffer.from([altResult[18], altResult[39], altResult[60]])),
    radix64(Buffer.from([altResult[40], altResult[61], altResult[19]])),
    radix64(Buffer.from([altResult[62], altResult[20], altResult[41]])),
    radix64(Buffer.from([0, 0, altResult[63]])).slice(0, 2),
  ].join('')

  return result
}

const radix64Encoder =
  './0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz'
function radix64(buffer) {
  let v = (buffer[0] << 16) | (buffer[1] << 8) | buffer[2]
  const c1Idx = v & 0x3f
  v = v >> 6
  const c2Idx = v & 0x3f
  v = v >> 6
  const c3Idx = v & 0x3f
  v = v >> 6
  const c4Idx = v & 0x3f
  v = v >> 6

  return (
    radix64Encoder[c1Idx] +
    radix64Encoder[c2Idx] +
    radix64Encoder[c3Idx] +
    radix64Encoder[c4Idx]
  )
}

const password = '123456'
const salt = 'PCjFvrAA/NnyKdMp'

const encryptPassword = sha512crypt(password, salt)

console.log(encryptPassword)

# openssl passwd -6 -salt PCjFvrAA/NnyKdMp 123456
$6$PCjFvrAA/NnyKdMp$7fs0mn0nUuQ0jjtKZVAyf8TCBIx5MUvwC2ftkRwh2q7PYSuKpnv4wVu63zX.oCJ/RG2v4gDbNMCDAV1dIjCuE.