String to hexbytestring and back

-- original strlen: 16
-- hex strlen: 32= orig*2

-- Base functions
function ToByte(str)
    assert(type(str) == "string")
    return string.format(("%02x"):rep(str:len()), string.byte(str, 1, str:len()))
end

local function hextochar(hexstr) return string.char(tonumber(hexstr, 16)) end
function FromByte(str)
    assert(type(str) == "string")
    return string.gsub(str, "%x%x", hextochar)
end

local str = "Some test string"
local byteval = ToByte(str) -- Convert to byte
local orig = FromByte(byteval) -- Convert back to original string

-- Print lengths and content of each string used
print(str:len(), "'"..str.."'")
print(byteval:len(), "'"..byteval.."'")
print(orig:len(), "'"..orig.."'")