Cryptographically secure API key/secure token batch generation generator | ZeroTools

Securely generate API keys, UUIDs, and private key tokens in bulk using a cryptographically secure random number generator (CSPRNG). It is a convenient web tool that operates completely locally and safely without sending data to an external server.

Generation parameters

Customize the format and length of the token.

token format

Source strength (bytes)32

Number of output characters: 64 characters

Number of generated tokens5

Generation results

Strings generated with Web Crypto. Resistance to guessing depends on the alphabet size and length.

Please adjust the parameters and generate the token.

crypto entropy256 bits

Prediction strength evaluationExtremely safe

Recommended uses and precautionsIdeal for areas that require strong security such as encryption keys, session IDs, and CSRF tokens.

Characteristics and use cases of each token format

■ Hexadecimal number (Hex)

Expressed only with 0~9, a~f. Because the byte length is simply half the number of characters, it is ideal as a shared secret for signing HMAC authentication codes or as a secret key for signing JWT.

■ Base64 / Base64URL

Encode information using 64 secure characters. In particular, Base64URL excludes `+` / `/` and replaces it with `-` `_`, and can be used directly in HTTP cookie values, URL query parameters, OAuth CSRF state, etc.

■ UUID v4

A globally unique identifier created from a length of 128 bits. Since the possibility of collision is negligible in a distributed system, it is ideal for the primary key of a database or the initial value of a file name.

■ Alphanumeric mix/custom

Suitable for secure API access tokens, initialization passwords for users, gift codes, access URL pin codes, etc. By using similar character exclusion, you can prevent users from making input errors.

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Client-Side Secure Execution

This tool executes entirely in your browser sandbox. None of your input strings, files, or configurations are uploaded to any external server.

ZeroTools: Browser Processing & Privacy

ZeroTools focuses on tools that process input on your device. Check each tool’s scope and limitations before use.

Processing and privacy policy

Article Index

Chapter 1

Technical Specifications & Architecture

Choose a format and length

Hex, Base64 and Base64URL encode the selected number of random bytes. For example, 32 bytes produce 64 hexadecimal characters. Base64URL uses URL-friendly characters without padding. Alphanumeric and custom modes measure length in characters. UUID mode produces a fixed-format version 4 identifier.

Custom mode uses only the supplied characters and treats repeated characters as one choice. An empty alphabet stops generation. Character selection avoids modulo bias, but does not guarantee that every selected character category appears in each token.

Randomness comes from Web Crypto on your device; generation stops if it is unavailable. This tool does not register credentials, set expiry dates, grant permissions or mask displayed tokens. Check where you copy or save the output.

Frequently Asked Questions (FAQ)

Hex, Base64 and Base64URL use source bytes. Alphanumeric and custom modes use characters. UUID v4 has a fixed length.

Generation stops and previous results are cleared. Repeated characters count as one choice. Changing the alphabet updates the output.

No. This generates a string, not a registered credential. Registration, permissions, expiry and storage must be configured in the receiving system.

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Client-Side Secure Execution

ZeroTools: Browser Processing & Privacy