Welcome to the second course in the OWASP Top 10 series! 🔐 In this course, we'll explore cryptographic failures, one of the most critical security risks in modern applications. Cryptographic failures occur when sensitive data is not properly encrypted, leading to unauthorized access, data breaches, and compliance violations.

In the previous course, you secured the pastebin application against broken access control vulnerabilities. Now, we shift our focus to another major attack vector: poor cryptographic practices that expose sensitive data. While encryption is meant to protect confidential information, improper implementation can render it useless — or worse, provide a false sense of security that attackers can easily bypass.

Modern applications are custodians of sensitive information, including passwords, credit card details, personal data, and API keys. If this data is not properly protected, attackers can intercept, manipulate, or extract it, leading to severe consequences for both users and the organization. A single cryptographic weakness can undermine the security of the entire system.

Common causes of cryptographic failures include:

• Hardcoded secrets in source code, which become exposed to anyone with access to the repository.
• Weak or outdated encryption algorithms (like DES or RC4) that can be cracked with modern computing power.
• Improper password hashing, such as using fast algorithms like MD5 or SHA-1 without a salt, allowing attackers to easily reverse-engineer or brute-force credentials.

These failures don't just result in data leaks — they erode user trust, violate privacy laws (e.g., GDPR, PCI DSS), and expose organizations to significant legal and financial penalties. A single cryptographic mistake can have a lasting negative impact on a business's reputation and bottom line.

In this course, you'll get hands-on experience identifying and fixing critical cryptographic weaknesses in the pastebin application. You will learn to:

• Identify and eliminate hardcoded secrets from the codebase, replacing them with secure secret management practices.
• Implement strong, modern encryption to protect sensitive data at rest in the database.
• Securely store user passwords by implementing robust key derivation functions like Argon2 or bcrypt.

By the end of this course, you'll have a solid understanding of cryptographic best practices and the practical skills to apply them in real-world applications.

In the next unit, we'll dive into one of the most common and dangerous mistakes: hardcoded secrets. This happens when sensitive credentials like encryption keys, passwords, and API tokens are stored in plain text directly within the codebase. You'll see just how easily attackers can exploit this flaw and learn how to properly manage secrets using environment variables and other secure methods.

Let's strengthen the cryptographic security of our application and ensure sensitive data stays protected! 🚀