Verifying Login Passwords with password_verify()

Compare a submitted password with its stored adaptive password hash using password_verify. The examples separate the essential operation from the conditions a production implementation must enforce.

What It Does

Compare a submitted password with its stored adaptive password hash using password_verify.

Prerequisites

Use a dedicated development environment with test accounts and records. Separate authorization, validation and error handling from response formatting; never copy demonstration-only secrets into production.

Example 1: Core Behavior

The first example isolates the core operation so its result is easy to understand.

<?php
$stored = password_hash('test-passphrase', PASSWORD_DEFAULT);
echo password_verify('test-passphrase', $stored) ? 'Logged in' : 'Denied';

Example 2: Alternative or Failure Case

The second example demonstrates an alternative outcome, rule or failure condition.

<?php
$stored = password_hash('valid-password', PASSWORD_DEFAULT);
echo password_verify('invalid-password', $stored) ? 'Accepted' : 'Rejected';

Practical Example: Applying the Rule

The practical example shows how to carry the same constraint into application code.

<?php
$stored = password_hash('demo', PASSWORD_DEFAULT);
if (password_verify('demo', $stored) && password_needs_rehash($stored, PASSWORD_DEFAULT)) { $stored = password_hash('demo', PASSWORD_DEFAULT); }
echo 'Authentication checked';

Important Behavior and Edge Cases

Always use the whole stored hash and generic login errors; apply rate limits and secure sessions.

Comparison with Related Functions or Patterns

Common Beginner Mistakes

Key Takeaways

• Compare a submitted password with its stored adaptive password hash using password_verify.
• Always use the whole stored hash and generic login errors; apply rate limits and secure sessions.
• password_needs_rehash detects whether to update cost parameters after login.

Select this API or pattern based on its documented behavior and the trust boundaries in your own application, and test all external integrations against their actual deployments.