Secure random strings are essential for API keys, authentication tokens, session IDs, encryption keys, and other security-sensitive identifiers. This tool generates cryptographically secure random strings using the Web Crypto API (crypto.getRandomValues). You can customize the length, character set (uppercase, lowercase, digits, special characters), and format.
Set the desired string length using the slider or number input, select which character sets to include (uppercase, lowercase, digits, special characters), and click 'Generate'. You can generate multiple strings at once. Each generated string can be copied individually, or all strings can be copied as a list.
Random strings are used for API keys and secret tokens, database seed values, temporary passwords and one-time codes, CSRF tokens in web forms, nonce values for cryptographic operations, unique file and directory names, session identifiers, salt values for password hashing, webhook signing secrets, and test data generation for automated testing suites.
The generator uses crypto.getRandomValues() to fill a Uint32Array with cryptographically secure random numbers, then maps each value to a character from the selected character set using modulo operation. The entropy per character depends on the character set size: ~5.95 bits for alphanumeric (62 chars), ~6.55 bits for full printable ASCII (94 chars).
The strings are generated using the Web Crypto API (crypto.getRandomValues), which provides cryptographically secure pseudo-random numbers. This is the same source of randomness used by browsers for TLS/SSL connections.
You can include uppercase letters (A-Z), lowercase letters (a-z), digits (0-9), and special characters (!@#$%^&*). Any combination of these sets can be selected.
For API keys and tokens, 32-64 characters is common. For passwords, 16+ characters with mixed character sets provides strong security. For encryption keys, use the exact key length required by your algorithm (e.g., 32 bytes for AES-256).
Transform, format, generate, and encode data instantly. Private, fast, and always free.
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