-1' OR 64=64 or 'DjalrbRJ'='

That string looks like an SQL injection payload. It’s trying to break out of a quoted input in a SQL query and inject a tautology (64=64) so the WHERE clause always evaluates to true, which could let an attacker bypass authentication or leak data.

What it does, at a high level:

• The -1' tries to terminate a previous string literal.
• OR 64=64 is always true, so it can override the intended conditions.
• or 'DjalrbRJ'='' adds another condition that’s typically false, but the presence of the true clause (64=64) is what matters.
• Overall, if the application concatenates user input into a SQL query without proper safeguards, this can turn a restricted query into something that returns rows regardless of the login credentials.

How to defend (important for exams and real systems):

• Use prepared statements / parameterized queries. Do not concatenate user input into SQL.
  • Example (pseudo):
    • Unsafe: "... WHERE username = '" + user + "' AND password = '" + pass + "'"
    • Safe: "SELECT * FROM users WHERE username = ? AND password = ?"; set parameters with user and pass
• Validate and constrain input:
  • Whitelist allowed characters and lengths for inputs (e.g., usernames).
• Never rely on escaping alone.
• Use least privilege for the database account (e.g., no DROP or ALTER permissions from the web app user).
• Store passwords securely (strong hash + salt, e.g., bcrypt, argon2).
• Disable or mitigate multiple statements if your DB supports them.
• Return generic error messages; avoid leaking details that help an attacker.
• Implement application security tests (input fuzzing, SQLi testing) and consider a web application firewall.

If you want, tell me your programming language and I can show a concrete secure code snippet for that environment. And a quick note: never test injection on systems you don’t own or have permission to test.