CUID Generator

Introduction

A CUID (Collision-resistant Unique IDentifier) is a unique identifier designed to be collision-resistant, horizontally scalable, and sequentially sortable. CUIDs are particularly useful in distributed systems where unique identifiers need to be generated without coordination between nodes.

Structure of CUIDs

A CUID typically consists of the following components:

1. Timestamp: A representation of the current time
2. Counter: A sequential counter to ensure uniqueness within the same millisecond
3. Client fingerprint: A unique identifier for the machine or process generating the CUID
4. Random component: Additional random data to further reduce collision probability

The exact structure may vary depending on the CUID implementation, but these components work together to create a unique and sortable identifier.

Here's a visual representation of a typical CUID structure:

How CUIDs are Generated

CUIDs are generated using a combination of time-based and random components. The process typically involves:

1. Getting the current timestamp
2. Incrementing a counter (which resets periodically)
3. Generating a client fingerprint (usually done once per session or application start)
4. Adding random data
5. Combining these elements in a specific format

The resulting CUID is typically represented as a string of letters and numbers.

Advantages and Use Cases

CUIDs offer several advantages over other unique identifier systems:

1. Collision resistance: The combination of timestamp, counter, and random data makes collisions extremely unlikely, even in distributed systems.
2. Horizontal scalability: CUIDs can be generated independently on multiple machines without coordination.
3. Sequential sorting: The timestamp component allows for chronological sorting of CUIDs.
4. URL-friendly: CUIDs are typically composed of URL-safe characters.

Common use cases for CUIDs include:

• Database primary keys
• Distributed systems where unique IDs need to be generated across multiple nodes
• Session IDs in web applications
• Tracking events in analytics systems
• File or resource naming in cloud storage systems

Code Examples

Here are examples of generating CUIDs in various programming languages:

1// JavaScript (using the 'cuid' library)
2const cuid = require('cuid');
3const id = cuid();
4console.log(id);
5

1## Python (using the 'cuid' library)
2import cuid
3id = cuid.cuid()
4print(id)
5

1## Ruby (using the 'cuid' gem)
2require 'cuid'
3id = Cuid::generate
4puts id
5

1// Java (using the 'com.github.f4b6a3.cuid' library)
2import com.github.f4b6a3.cuid.Cuid;
3
4public class CuidExample {
5    public static void main(String[] args) {
6        String id = Cuid.createCuid();
7        System.out.println(id);
8    }
9}
10

1// C# (using the 'Cuid.Net' NuGet package)
2using Cuid;
3
4class Program
5{
6    static void Main(string[] args)
7    {
8        string id = CuidGenerator.Generate();
9        Console.WriteLine(id);
10    }
11}
12

1// PHP (using the 'endyjasmi/cuid' package)
2<?php
3require 'vendor/autoload.php';
4use Endyjasmi\Cuid\Cuid;
5
6$id = Cuid::make();
7echo $id;
8

1// Go (using the 'github.com/lucsky/cuid' package)
2package main
3
4import (
5    "fmt"
6    "github.com/lucsky/cuid"
7)
8
9func main() {
10    id := cuid.New()
11    fmt.Println(id)
12}
13

1// Swift (using the 'CUID' package)
2import CUID
3
4let id = CUID()
5print(id)
6

1// C++ (using a custom implementation)
2#include <iostream>
3#include <chrono>
4#include <random>
5#include <sstream>
6#include <iomanip>
7
8std::string generateCUID() {
9    auto now = std::chrono::system_clock::now();
10    auto now_ms = std::chrono::time_point_cast<std::chrono::milliseconds>(now);
11    auto value = now_ms.time_since_epoch();
12    long duration = value.count();
13
14    std::random_device rd;
15    std::mt19937 gen(rd());
16    std::uniform_int_distribution<> dis(0, 35);
17
18    std::stringstream ss;
19    ss << 'c';
20    ss << std::hex << std::setfill('0') << std::setw(8) << duration;
21    for (int i = 0; i < 8; i++) {
22        int r = dis(gen);
23        ss << (char)(r < 10 ? '0' + r : 'a' + r - 10);
24    }
25    return ss.str();
26}
27
28int main() {
29    std::string id = generateCUID();
30    std::cout << id << std::endl;
31    return 0;
32}
33

1% MATLAB (using a custom implementation)
2function id = generateCUID()
3    timestamp = dec2hex(round(posixtime(datetime('now'))*1000), 8);
4    random = '';
5    for i = 1:8
6        random = [random char(randi([48 57 97 122]))];
7    end
8    id = ['c' timestamp random];
9end
10
11% Usage
12id = generateCUID();
13disp(id);
14

1## R (using a custom implementation)
2library(lubridate)
3
4generate_cuid <- function() {
5  timestamp <- format(as.numeric(now()) * 1000, scientific = FALSE)
6  timestamp <- substr(timestamp, 1, 8)
7  random <- paste0(sample(c(0:9, letters[1:6]), 8, replace = TRUE), collapse = "")
8  paste0("c", timestamp, random)
9}
10
11## Usage
12id <- generate_cuid()
13print(id)
14

1' Excel VBA (using a custom implementation)
2Function GenerateCUID() As String
3    Dim timestamp As String
4    Dim random As String
5    Dim i As Integer
6    
7    timestamp = Right("00000000" & Hex(CLng(CDbl(Now()) * 86400000)), 8)
8    
9    For i = 1 To 8
10        random = random & Mid("0123456789abcdef", Int(Rnd() * 16) + 1, 1)
11    Next i
12    
13    GenerateCUID = "c" & timestamp & random
14End Function
15
16' Usage in a cell
17'=GenerateCUID()
18

History and Development

CUIDs were originally developed by Eric Elliott in 2012 as a solution to the problem of generating unique identifiers in distributed systems. The concept was inspired by Twitter's Snowflake ID system but designed to be more easily implemented and used across various platforms.

The development of CUIDs was driven by the need for a simple, collision-resistant ID system that could work across different programming languages and environments. Elliott's goal was to create a system that was easy to implement, didn't require central coordination, and could scale horizontally.

Since its inception, CUID has gone through several iterations and improvements:

1. The original CUID implementation focused on simplicity and ease of use.
2. As adoption grew, the community contributed implementations in various programming languages.
3. In 2021, CUID2 was introduced to address some limitations of the original CUID and provide even better performance and collision resistance.
4. CUID2 improved upon the original by using a more secure random number generator and increasing the overall length of the identifier.

The evolution of CUIDs reflects the changing needs of distributed systems and the ongoing efforts to balance simplicity, security, and performance in unique identifier generation.

References

1. Official CUID GitHub Repository
2. CUID2 Specification
3. Elliott, Eric. "Generating Unique IDs in a Distributed Environment." Medium, 2015.
4. "Collision-resistant IDs for Distributed Systems." DZone, 2018.

This CUID generator tool allows you to quickly generate CUIDs for your projects. Simply click the "Generate" button to create a new CUID, and use the "Copy" button to copy it to your clipboard for easy use in your applications.