SHA-256

Audit of 25 Package Managers Shows Only Two Verify Every Package's Integrity Against Compromised Repositories

A comprehensive test by Trail of Bits examined 25 popular package managers to determine whether they detect malicious code substituted by a compromised repository. The study found that fewer than half verify package integrity by default using lockfiles, and only two managers check the cryptographic hash of every downloaded package. Most managers either require manual configuration, use hashes insecurely, or lack any integrity checks even when lockfiles are present. Signature verification is even rarer, with only Go performing checks by default. The research used a Docker and mitmproxy testbed to simulate attacks while preserving realistic conditions. Results highlight significant gaps in supply-chain protections across ecosystems including JavaScript, Python, Ruby, Rust, and others. The findings also discuss limitations of current lockfile designs and emerging improvements in several communities.

Hash Functions Part 1: Core Properties, Security Requirements and Practical Applications

The article provides a detailed introduction to hash functions, explaining how they map arbitrary-length input to fixed-length output while satisfying three fundamental security properties. It covers preimage resistance, second preimage resistance, and collision resistance, along with the avalanche effect that makes even minor input changes produce unrecognizable output. The text explains why a 256-bit digest is required to achieve 128-bit collision resistance, referencing the birthday paradox and its implications for MD5 and SHA-1. Practical guidance includes using OpenSSL for hashing, applying hashes in commitment schemes, enforcing subresource integrity on web pages, and securely storing passwords with Argon2 and bcrypt. The post emphasizes that hash functions alone do not guarantee integrity without proper transmission of the digest and announces a follow-up on SHA-2 and SHA-3 internals.

Bcrypt Password Hashing Silently Ignores Characters Beyond 72 Bytes, Breaking Verification Expectations

The bcrypt algorithm, widely used for password hashing in PHP and Python applications, processes only the first 72 bytes of any input password. Additional characters are ignored without error or warning during both hashing with password_hash and verification with password_verify. This behavior stems from the fixed 72-byte P-table size in the underlying Blowfish cipher as defined in the 1999 specification. Long passphrases, especially those using multibyte UTF-8 characters like Cyrillic or emojis, can result in completely different strings producing identical hashes. The limitation creates risks during password manager usage, system migrations, and scenarios involving shared prefixes. Modern libraries such as Python's bcrypt 4.x now explicitly reject passwords exceeding 72 bytes, while older implementations continue silent truncation. Recommended fixes include enforcing byte-length validation or pre-hashing with SHA-256 before bcrypt.

Pilcrow Publishes Free Comprehensive Guide on Web Authentication

Author Pilcrow has released a detailed, ad-free handbook covering authentication and authorization practices for web applications. The resource draws on personal experience and includes practical examples in JavaScript and Go. It examines password-based methods, email verification, multi-factor authentication, passwordless flows, and passkeys while highlighting associated risks and usability trade-offs. The book also provides in-depth guidance on session management, token security, expiration policies, and email address handling as account identifiers. Recommendations emphasize choosing methods that match application security requirements and user expectations. Additional context is given on OWASP resources and community support channels.

Spring Security Tutorial Details Refresh Token Implementation to Complement JWT Authentication

A detailed technical guide explains how to enhance JWT-based authentication in Spring Security by introducing refresh tokens for improved security and user experience. The article covers the creation of a RefreshToken entity stored in the database, along with repository and service layers that handle token generation, verification, revocation, and rotation using UUID and expiration timestamps. It discusses security advantages such as short-lived access tokens combined with long-lived refresh tokens hashed via SHA-256 or HMAC-SHA256, while also addressing risks including database theft and XSS attacks mitigated by HttpOnly cookies. Code examples demonstrate updates to AuthService, AuthController, and SecurityConfig to support registration, login, token refresh via cookies, and logout functionality. Additional best practices include automatic token rotation on refresh and session management across multiple devices. The tutorial emphasizes minimizing credential transmission over networks while maintaining stateful token validation.