16 Random Bytes

What Random Bytes Actually Are

A byte is eight bits, each independently 0 or 1, producing 256 possible values (0 through 255). Generating N random bytes means drawing N independent samples. The entropy is exactly N × 8 bits. Sixteen bytes yield 128 bits of entropy: 3.4 × 10³⁸ possible outcomes. Thirty-two bytes yield 256 bits: more possible outcomes than atoms in the observable universe.

Where Random Bytes Get Used

• Encryption keys: AES-128 requires 16 bytes; AES-256 requires 32.
• Initialization vectors: prevent identical plaintexts from producing identical ciphertexts. Typically 12 or 16 bytes.
• Salts: prepended to passwords before hashing. OWASP recommends at least 16 bytes.
• Nonces and CSRF tokens: single-use values preventing replay and forgery attacks.

Three Formats, One Source

Hexadecimal encodes each byte as two characters (0-9, A-F). Base64 encodes three bytes into four ASCII characters. Binary shows each byte as eight digits. The information content is identical across all three. The format tabs switch the display without regenerating.

The Entropy Source

Each generation calls crypto.getRandomValues(), the Web Cryptography API built into every modern browser. It draws from hardware-level entropy: thermal noise, electrical jitter, and interrupt timing. The byte frequency histogram demonstrates uniformity visually as you generate more bytes.

Private by Architecture

Every byte is generated inside your browser and never transmitted. The raw bytes exist only in your device's memory and clipboard. The server delivered this page; your device created the randomness.

Configure Through the URL

• /bytes — 16 bytes, hex
• /bytes/32 — 32 bytes
• /bytes/64/base64 — 64 bytes, Base64
• /bytes/16/bin — 16 bytes, binary