SHA1 and Base64 implemented for nodemcu using bit library.

sha1.lua

do
  local byte, char = string.byte, string.char
  local floor = math.floor
  local rshift = bit.rshift
  local lshift = bit.lshift
  local band = bit.band
  local bor = bit.bor
  local bnot = bit.bnot
  local bxor = bit.bxor

  local function leftrotate(num, b)
    return bor(lshift(num, b), rshift(num, 32 - b))
  end

  function sha1(message)
    local len = #message
    local high = floor(len / 0x20000000)
    local low = (len * 8) % 100000000

    local function slot(g, o)
      local i = g + o
      if i <= len then
        return byte(message, i)
      elseif i == len + 1 then
        return 0x80
      elseif o <= 56 or len >= g + 56 then
        return 0
      elseif o <= 60 then
        return rshift(high, (60 - o) * 8) % 256
      else
        return rshift(low, (64 - o) * 8) % 256
      end
    end

    local h0, h1, h2, h3, h4 = 0x67452301, 0xEFCDAB89, 0x98BADCFE, 0x10325476, 0xC3D2E1F0

    local w = {}
    for g = 0, len + 8, 64 do
      for i = 0, 15 do
        local b = i * 4
        w[i] = bor(
          lshift(slot(g, b + 1), 24),
          lshift(slot(g, b + 2), 16),
          lshift(slot(g, b + 3), 8),
          slot(g, b + 4)
        )
      end
      for i = 16, 79 do
        w[i] = leftrotate(bxor(w[i - 3], w[i - 8], w[i - 14], w[i - 16]), 1)
      end

      local a, b, c, d, e = h0, h1, h2, h3, h4
      local function process(f, k, s)
        a, b, c, d, e =
          leftrotate(a, 5) + f + e + k + s,
          a, leftrotate(b, 30), c, d
      end
      for i = 0, 19 do
        process(bor(band(b, c), band(bnot(b), d)), 0x5A827999, w[i])
      end
      for i = 20, 39 do
        process(bxor(b, c, d), 0x6ED9EBA1, w[i])
      end
      for i = 40, 59 do
        process(bor(band(b, c), band(b, d), band(c, d)), 0x8F1BBCDC, w[i])
      end
      for i = 60, 79 do
        process(bxor(b, c, d), 0xCA62C1D6, w[i])
      end
      h0 = rshift(h0 + a, 0)
      h1 = rshift(h1 + b, 0)
      h2 = rshift(h2 + c, 0)
      h3 = rshift(h3 + d, 0)
      h4 = rshift(h4 + e, 0)
    end

    return char(
      rshift(h0, 24),
      band(rshift(h0, 16), 0xff),
      band(rshift(h0, 8), 0xff),
      band(h0, 0xff),
      rshift(h1, 24),
      band(rshift(h1, 16), 0xff),
      band(rshift(h1, 8), 0xff),
      band(h1, 0xff),
      rshift(h2, 24),
      band(rshift(h2, 16), 0xff),
      band(rshift(h2, 8), 0xff),
      band(h2, 0xff),
      rshift(h3, 24),
      band(rshift(h3, 16), 0xff),
      band(rshift(h3, 8), 0xff),
      band(h3, 0xff),
      rshift(h4, 24),
      band(rshift(h4, 16), 0xff),
      band(rshift(h4, 8), 0xff),
      band(h4, 0xff)
    )
  end

  local bytes =
    "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/"

  function base64(s)
    local parts = {}
    for i = 1, #s, 3 do
      local a, b, c = byte(s, i, i + 3)
      parts[#parts + 1] = char(
        byte(bytes, rshift(a, 2) + 1),
        byte(bytes, bor(lshift(band(a, 3), 4), rshift(b or 0, 4)) + 1),
        b and byte(bytes, bor(lshift(band(b, 15), 2), rshift(c or 0, 6)) + 1) or 61,
        c and byte(bytes, band(c, 63) + 1) or 61)
    end
    return table.concat(parts)
  end

end

test.lua

dofile("sha1.lua")

local function dump(hash)
  local hex = {}
  for i = 1, #hash do
    hex[i] = string.format("%02x", string.byte(hash, i))
  end
  return table.concat(hex)
end

-- Test data from http://www.nsrl.nist.gov/testdata/ and Wikipedia
-- http://csrc.nist.gov/groups/ST/toolkit/documents/Examples/SHA_All.pdf

local tests = {
  "2fd4e1c67a2d28fced849ee1bb76e7391b93eb12", "The quick brown fox jumps over the lazy dog",
  "de9f2c7fd25e1b3afad3e85a0bd17d9b100db4b3", "The quick brown fox jumps over the lazy cog",
  "da39a3ee5e6b4b0d3255bfef95601890afd80709", "",
  "a9993e364706816aba3e25717850c26c9cd0d89d", "abc",
  "84983e441c3bd26ebaae4aa1f95129e5e54670f1", "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq",
  "34aa973cd4c4daa4f61eeb2bdbad27316534016f", ("a"):rep(1000000),
}

for i = 1, #tests, 2 do
  local expected = tests[i]
  local input = tests[i + 1]
  local actual = dump(sha1(input))
  assert(expected == actual, expected)
end

tests = {
  "L9ThxnotKPzthJ7hu3bnORuT6xI=", "The quick brown fox jumps over the lazy dog",
  "3p8sf9JeGzr60+haC9F9mxANtLM=", "The quick brown fox jumps over the lazy cog",
  "2jmj7l5rSw0yVb/vlWAYkK/YBwk=", ""
}
for i = 1, #tests, 2 do
  local expected = tests[i]
  local input = tests[i + 1]
  local actual = base64(sha1(input))
  assert(actual == expected, expected)
end