Adventures in Machine Learning

Generating Secure and Random Strings and UUIDs in Python

Generating Random Strings in Python: How to Make it More Secure

Are you wondering how to generate random strings in Python? Whether you need to create passwords, API keys, or other identifiers for your project, Python offers various approaches to meet your requirements.

In this article, we’ll dive into two primary methods for generating random strings: building a string from a random integer sequence and using the string module. We’ll also discuss how to make your random generation more secure by using the random.SystemRandom() function.

Approach 1: Building a String from a Random Integer Sequence

One of the simplest ways to generate random strings is to build them from a random integer sequence. To do this, we’ll start by using the random module in Python, which provides various functions to generate random numbers.

We can use the chr() function to convert a random integer to its corresponding ASCII character. For example, chr(65) returns ‘A’, chr(97) returns ‘a’, and so on.

Once we have a set of random ASCII integers, we can concatenate them to form a random string. Here’s an implementation of this approach:


import random

def generate_random_string(length):

result = “”

for i in range(length):

rand_num = random.randint(32, 126)

result += str(chr(rand_num))

return result


In the code above, we are using the range() function to loop through the string of the desired length. For each iteration, we generate a random number between 32 and 126, which represents the printable ASCII characters, excluding the backspace and delete characters.

We then convert this number to its corresponding ASCII character using chr(), append it to the result string, and return the final result. While this approach is simple and straightforward, it has a few limitations.

Since it only generates printable ASCII characters, the resulting string may not contain special characters or other non-printable characters. Additionally, the random sequence of characters generated may not be cryptographically secure, so it might not be safe for sensitive use cases.

Approach 2: Using the String Module for Generating Random Strings

Another way to generate random strings in Python is to use the string module, which provides a list of all possible characters we can use. We can then use the random.choice() method to pick a random character from this list to create a random string.

Here’s an example implementation of this approach:


import random

import string

def generate_secure_random_string(length):

return ”.join(random.choices(string.ascii_letters + string.digits + string.punctuation, k=length))


In the code above, we are using the string module to define the set of characters that we want to use – letters (both upper and lower case), digits, and punctuation characters. We are then using the random.choice() function to randomly pick a character from this set for the desired length of the string.

This approach is more secure than the previous one since it includes a broader range of characters, including special characters. Additionally, the random string generator function provided by this approach has been deemed cryptographically secure.

Making the Random Generation More Secure

While the random module offers ways for creating randomized characters and strings, it does have limitations in terms of its randomness. For secure string generation, we recommend using the random.SystemRandom() function added in Python 2.4.

The random.SystemRandom() is a subclass of the random module, intended to use the random number generator present in the operating system.

Since the random number generator within the OS usually provides truly random values, the random numbers generated through this function are more secure. Using the random.SystemRandom() function is straightforward.

Here’s an example implementation of the previous secure random string generator but with random.SystemRandom() as the RNG generator:


import random

import string

rng = random.SystemRandom()

def generate_secure_random_string(length):

return ”.join(rng.choice(string.ascii_letters + string.digits + string.punctuation) for i in range(length))


In the code above, we first create a random.SystemRandom() object, which is assigned to the rng variable. We then use this object to create the random secure string by looping through the desired length and picking a random character out of our defined set of letters, digits, and punctuations.

This approach would ensure that the resulting random strings are truly random, unpredictable, and cryptographically secure.


We’re living in an era where data protection, security, and privacy are paramount concerns. Whether you’re protecting sensitive user data or participating in bug bounties, generating secure random strings is crucial.

In this article, we have discussed two approaches to generating random strings in Python: building a string from a random integer sequence and using the string module. We’ve also recommended the use of random.SystemRandom() for more secure string generation that is more suitable for highly sensitive information.

By employing these techniques, you can generate random strings across your projects with more confidence.

Generating Random UUID Strings in Python

When building applications that require unique identifiers, one easy-to-use solution is to use universally unique identifiers (UUIDs). UUIDs are 128-bit values that are globally unique, making them a reliable way to generate unique values across different systems.

In Python, the uuid module provides a straightforward way to generate random UUID strings. In this article, we will cover how to utilize the uuid module in Python to generate random UUID strings.

We will dive into the uuid module’s different functions and how they work. We will also discuss what UUIDs are, why they are essential, and a few use cases that can benefit from utilizing UUIDs.

What are UUIDs?

Universally Unique Identifiers (UUIDs) are standardized identifiers that are unique across the world. UUIDs have a length of 36 characters and consist of hexadecimal digits, which allow for a nearly infinite number of unique values.

UUIDs are used for various purposes, including identifying objects and resources in computer systems, as well as tracking unique transactions and user activities in databases. Why Use UUIDs?

UUIDs have several advantages over incrementing numeric identifiers and other traditional methods of generating unique IDs. For one, UUIDs do not require any centralized management or synchronization. UUIDs can also be generated on multiple servers simultaneously, without the risk of creating duplicate IDs.

Additionally, UUIDs can be generated off-network, meaning that if different systems generate UUIDs, they will not conflict.

As a result, UUIDs provide a simple way to connect entities across multiple systems, teams, and applications.

Using the uuid module

Python’s built-in uuid module allows developers to generate UUIDs in their code. With the uuid module, we can use different functions to generate UUID strings, including the uuid1() and

uuid4() functions.

uuid1() function


uuid1() function generates a UUID based on the host ID and current timestamp. The generated UUID includes a node address, which may reveal the identity of the node that generated the UUID.

This function is primarily intended for generating UUIDs for system and network environment use cases. Here’s an example implementation that uses

uuid1() function:


import uuid

id_ = uuid.uuid1()



In the code above, we imported the uuid module, called the

uuid1() function, and assigned the output to the id_ variable. The output of this function call is a UUID string.

uuid4() function


uuid4() function, on the other hand, generates random UUIDs, which do not include a node address or a time component. This function uses random bits in place of the node and time components to create a truly random UUID.

Here’s an example implementation that uses

uuid4() function:


import uuid

id_ = uuid.uuid4()



In the code above, we imported the uuid module, called the

uuid4() function, and assigned the output to the id_ variable. The output of this function call is a UUID string.

Note that there are no parameters required for the

uuid4() function, and it generates unique UUIDs every time it is called. As a result, it is an ideal solution for generating random UUID strings for various use cases that require unique IDs across the systems.


In this article, we have covered how to utilize the uuid module in Python to generate random UUID strings. We have discussed the essential features, advantages, and use cases of UUIDs and the different functions provided by the uuid module.

By using the uuid module’s two primary functions, uuid1() and uuid4(), you can generate UUID strings that are globally unique, helping to secure your applications and systems against related security issues. Remember to consider your usage requirements and choose functions such as uuid1() to generate UUIDs based on a node address and current timestamp or uuid4() for completely random UUID generation.

In this article, we’ve explored the usefulness of universally unique identifiers (UUIDs) and how to create random UUID strings in Python using the uuid module. We’ve discussed two primary functions provided within the module, uuid1() and uuid4(), and provided example usage scenarios.

UUIDs offer a unique way to create identifiers that have varying use cases, including tracking user activity, identifying objects and resources across multiple systems, and transaction management. By using the uuid module in Python, developers can generate UUID strings with ease, offering universally unique values across different systems.

As a result, we can conclude that incorporating UUIDs in system design is an important consideration for secure development practices.

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