How to Resolve Invalid Password Issues When Using bcrypt in Node.js Login

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Understanding the Problem

When a user tries to log in, their inputted password is hashed and compared to the hash stored in the database. If these hashes don't match, an "Invalid Password" error is returned. Common reasons for this mismatch include:

Different Salt Rounds: The number of hashing rounds (salt rounds) used during password generation and verification must match.

Data Storage Issues: Hash values may get corrupted during storage or retrieval due to various reasons.

Incorrect Hash Comparison: Not using bcrypt's comparison methods correctly can result in mismatches.

Inconsistent Password Fields: Slight changes in the input password or potential trailing spaces can also lead to mismatches.

Steps to Resolve the Issue

Verify Salt Rounds

Ensure that the salt rounds used for hashing the password during registration are the same as those used during login verification. Here's an example of setting salt rounds in bcrypt:

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Check Database Operations

Make sure the hash stored in the database is not inadvertently altered:

Encoding Issues: Ensure that your database column storing the hashed password correctly supports the data type (e.g., VARCHAR(255) for MySQL).

Sanitization: Avoid sanitizing or altering the hashed password inadvertently before storing it.

Use bcrypt's Compare Function Correctly

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[[See Video to Reveal this Text or Code Snippet]]

Normalize User Input

Ensure that you normalize user input to avoid issues related to trailing spaces or different encodings:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion