Blowfish Encryption Tool - Free Online Blowfish Cipher

Encrypt and decrypt text with Blowfish cipher in your browser. Legacy 64-bit block cipher with variable key length. Free online Blowfish tool.

Legacy Algorithm: Blowfish uses 64-bit blocks. For new applications, consider AES encryption which uses 128-bit blocks and has hardware acceleration.

Blowfish Encryption

Password / Key

Key length: 4-56 bytes (32-448 bits)

Input Text

Output Ready

Base64

Hex

Algorithm Details

Cipher: Blowfish

Mode: CBC (Cipher Block Chaining)

Block Size: 64 bits (8 bytes)

Key Size: 32-448 bits (4-56 bytes)

Padding: PKCS7

IV: 8 bytes (prepended to output)

Designer Info

Designer: Bruce Schneier

Year: 1993

Patent: Unpatented, public domain

Successor: Twofish (AES finalist)

Security Notes

64-bit block size limits secure data volume
Don't encrypt more than ~4GB with same key
Use AES for new applications
Still suitable for small data

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Frequently Asked Questions

Blowfish is a symmetric block cipher designed by Bruce Schneier in 1993. It uses a 64-bit block size and variable key length (32-448 bits). Blowfish is unpatented and freely available.

Blowfish remains unbroken, but its 64-bit block size makes it vulnerable to birthday attacks on large data. For new applications, use AES (128-bit blocks). Blowfish is fine for legacy compatibility.

Blowfish is used in OpenSSH, password managers, bcrypt password hashing, and many legacy systems. It's also common in embedded systems due to its small memory footprint.

AES uses 128-bit blocks (more secure for large data), while Blowfish uses 64-bit blocks. AES has hardware acceleration on modern CPUs. Blowfish has slower key setup but fast encryption after setup.

bcrypt is a password hashing function that uses Blowfish internally. It applies the expensive Blowfish key schedule repeatedly to make brute-force attacks slow. Use bcrypt for passwords, not raw Blowfish.

This tool uses CBC (Cipher Block Chaining) mode with PKCS7 padding. A random IV is generated for each encryption and prepended to the output.

Blowfish supports keys from 32 bits (4 bytes) to 448 bits (56 bytes). Longer keys provide more security. This tool uses your password directly as the key (UTF-8 encoded).

Yes. All encryption happens in your browser using JavaScript. Your data and password never leave your device.

Blowfish Encryption

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