Blowfish Encryption & Decryption

Encrypt and decrypt text with Blowfish, key length of your choice.

Blowfish is weak by today's standards — use it to read old data; for new data use AES or ChaCha20. Go to AES

Text to encrypt

Encrypt with

Password

You'll need it again to decrypt. Nothing you type leaves this page.

PBKDF2 iterations

OpenSSL's default is 10,000. Any number works: more makes the password slower to guess; decrypting needs the same number.

Mode

The usual choice with OpenSSL. Needs an IV; pads to whole blocks.

Key size

Output as

Same with OpenSSL

openssl enc -bf-cbc -pbkdf2 -iter 10000 -a -A -provider legacy -provider default

OpenSSL asks for the password; paste the text into it, or add -in and -out files.

Encrypted text

Blowfish is Bruce Schneier's 1993 block cipher, with 8-byte blocks and a key of any length from 32 to 448 bits. It was a popular free alternative to DES and still turns up in older applications, file formats and configuration files. This page encrypts and decrypts text with Blowfish in CBC mode by default, or ECB, CFB, OFB or CTR, with any key length in 8-bit steps — 128 bits by default, the key size of OpenSSL's bf-cbc — using a password in the openssl enc -pbkdf2 format or your own hex key and IV. For new data use AES or ChaCha20. Everything runs in your browser, so your text and keys never leave your device; free, no sign-up.

How to encrypt or decrypt text with Blowfish

Choose Encrypt or Decrypt. Type the text to encrypt, or paste the Base64 or hex text to decrypt — the format is detected automatically.
Enter the password, or switch to Key & IV (hex) and enter the key and a 16-digit IV (ECB has no IV). A pasted key sets the key length by itself.
Pick the key length (128 bits unless the data was made with another) and the mode, usually CBC or ECB. Turn on No padding only if the data was encrypted without PKCS#7 padding.
Copy or download the result, or press Swap to move it into the input and flip the direction.

Features

Any key length from 32 to 448 bits in 8-bit steps, with 64, 128, 256 and 448 one click away
CBC, ECB, CFB, OFB and CTR modes; PKCS#7 padding or none
Password mode in the openssl enc -pbkdf2 format; the 128-bit default is what OpenSSL's bf-cbc uses
Key & IV mode: a hex key of 8 to 112 digits and a 16-digit IV
The openssl command for 128-bit keys in every mode but CTR, with OpenSSL 3's legacy provider
Base64 or hex in and out; copy, download or Swap the result

Is it private?

Yes. Blowfish runs in WebAssembly inside your browser. Your text, password and key are never uploaded or saved; the page keeps them only while it's open.

Frequently asked questions

Is Blowfish still secure?

Not for new data. No practical attack breaks Blowfish itself, but its 8-byte block makes large amounts of data under one key vulnerable (the Sweet32 attack), and its own designer has recommended newer ciphers instead. Use it to read existing data; for new data use AES or ChaCha20.

Can I decrypt it with OpenSSL?

Yes, with the default 128-bit key: echo 'U2FsdGVkX1…' | openssl enc -d -bf-cbc -pbkdf2 -iter 10000 -a -A -provider legacy -provider default. -bf-ecb, -bf-cfb and -bf-ofb cover the other modes, and in Key & IV mode use -K <32 hex digits> -iv <16 hex digits> instead of -pbkdf2 -iter. OpenSSL has no Blowfish CTR, and openssl enc always uses a 128-bit Blowfish key, so other key lengths can't be read with it.

Which key length should I choose?

The one the data was made with — 128 bits if you don't know, since that is what OpenSSL uses. In password mode the page derives a key of the chosen length from the password, so a different length gives a different key. In Key & IV mode the hex key's own length counts: paste it and the key length follows.

Is this the same as bcrypt?

No. bcrypt is a password-hashing function built on Blowfish's key setup, and a hash can't be decrypted. This page is Blowfish encryption, which can be reversed with the password or key. To hash or check passwords, use the Bcrypt tool.