Is the generated key truly random?

Yes. This tool uses crypto.getRandomValues(), the browser's cryptographically secure pseudo-random number generator (CSPRNG). It is the same entropy source used by TLS and cryptographic libraries — not Math.random(), which is not cryptographically safe.

Is any key sent to a server?

No. Generation runs entirely in your browser. No key material, bit-length selection, or any other data is transmitted over the network. You can disconnect from the internet and the tool still works.

Which bit-length should I use for AES encryption?

AES supports 128, 192, and 256-bit keys. AES-256 is the most common choice for high-security applications. AES-128 is also considered secure and is slightly faster. AES-192 is rarely used in practice.

What is the difference between the hex and base64 formats?

Both encode the exact same random bytes. Hex uses two characters (0–9, a–f) per byte, producing a longer string that is easy to read. Base64 uses 64 characters per group of 3 bytes, producing a shorter string. Use whichever format your library or configuration file expects.

Can I generate a non-standard key length?

Yes. Enter any bit-length in the custom field as long as it is a multiple of 8 (whole bytes) and between 8 and 4096 bits.

Hex Key Generator

Generate cryptographically secure random hex keys — 128, 192, 256, or 512-bit presets or any custom bit-length — with hex, base64, and raw bytes output plus one-click copy.

Key Length

Custom (bits, multiple of 8)

256 bits — 32 bytes

Hexadecimal

—

Base64

—

Raw Bytes (decimal octets)

—

Copied!

Summary

This tool generates cryptographically secure random keys using the browser's Web Cryptography API (crypto.getRandomValues). Choose a preset bit-length — 128, 192, 256, or 512 bits — or enter any custom length in bits (multiples of 8). Output is shown in three formats: hexadecimal, base64, and raw bytes (space-separated octets). Each format has its own copy button. Everything runs in your browser; no data is sent to any server.

How it works

Select a preset bit-length (128, 192, 256, or 512 bits) or enter a custom length.
Click Generate — crypto.getRandomValues() fills a typed array with random bytes.
Three output formats are shown: hex, base64, and space-separated raw bytes.
Click the copy button next to any format to copy it to your clipboard.
Click Generate again or change the bit-length to produce a fresh key at any time.

Use cases

Generate AES-128, AES-192, or AES-256 keys for symmetric encryption.
Create HMAC-SHA256 or HMAC-SHA512 signing keys for API authentication.
Produce random session secrets for web application configuration.
Generate initialization keys for custom encryption protocols.
Create key material for JWT secret generation or token signing.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu