Base64 is NOT Encryption: Security Myths Debunked

Base64 is NOT Security

One of the most common misconceptions in web development is that Base64 provides some form of security. It does not.

What Base64 Actually Does

Base64 is an encoding scheme, not encryption. The difference is crucial:

• Encoding: Transforms data format (reversible by anyone)
• Encryption: Secures data with a key (only reversible with the key)

A Dangerous Example

// NEVER DO THIS
const password = "secretpassword123";
const "secured" = btoa(password); 
// "c2VjcmV0cGFzc3dvcmQxMjM="
// Anyone can decode this instantly
atob("c2VjcmV0cGFzc3dvcmQxMjM=");
// "secretpassword123"

Real-World Vulnerabilities

• Basic Auth headers - Credentials are Base64 encoded, not encrypted
• JWT tokens - The payload is just Base64, anyone can read it
• "Hidden" API keys - Base64 in source code is not hidden

What to Use Instead

For actual security, use proper cryptographic methods:

// For passwords: Use hashing (server-side)
// bcrypt, Argon2, or PBKDF2
// For sensitive data: Use encryption
const subtle = window.crypto.subtle;
async function encrypt(plaintext, key) {
  const iv = crypto.getRandomValues(new Uint8Array(12));
  const encoded = new TextEncoder().encode(plaintext);
  
  const ciphertext = await subtle.encrypt(
    { name: "AES-GCM", iv },
    key,
    encoded
  );
  
  return { ciphertext, iv };
}

When Base64 IS Appropriate

• Embedding binary data in text formats
• Data URLs for images
• Transferring binary over text-only protocols
• Making binary data URL-safe (with Base64URL variant)