Encrypt and decrypt with Blowfish
BeetVPN

Input data

Input

Result

Result
Advanced options
Initialization vector — 8 bytes

PKCS#7PKCS#7 padding is applied automatically. In CBC mode, use a different random IV for every new encryption with the same key.

What is Blowfish?

Blowfish is a symmetric 64-bit block cipher with a variable key from 32 to 448 bits. The same key is used for encryption and decryption. This tool supports CBC and ECB modes and applies PKCS#7 padding.

CBCEach block depends on the previous one and an 8-byte IV. This is the preferred mode here for understanding historical Blowfish use.
ECBEach block is processed independently. Repeated patterns remain visible, so this mode should not protect structured data.
KeyBetween 4 and 56 bytes. A UTF-8 passphrase and a hexadecimal key do not represent the same bytes.
OutputBase64 is convenient for copying data; hexadecimal shows the exact bytes produced.

Blowfish is not bcrypt

bcrypt uses a derived construction called EksBlowfish to slow down password verification. A bcrypt hash is not Blowfish ciphertext and cannot be decrypted. The bcrypt page remains dedicated to password generation and verification.

Compatibility and security

Blowfish is now mainly useful for legacy compatibility and learning. Its 64-bit block size makes it less suitable for large data volumes. New applications should use a modern authenticated cipher provided by their platform, such as AES-GCM or ChaCha20-Poly1305.

FAQ

How long must the IV be?

Blowfish uses 8-byte blocks. A CBC IV must therefore contain exactly 8 bytes, or 16 hexadecimal characters.

Why does decryption report invalid padding?

The key, IV, mode or ciphertext probably does not match. Corrupted data produces the same symptom.

Should ECB be used?

ECB is included for compatibility tests and known vectors. It does not hide repeated blocks.

Practical notes

Blowfish is a legacy symmetric cipher with a 64-bit block size. This page encrypts and decrypts in CBC or ECB mode with a 4-to-56-byte key.

Block64 bits
ModesCBC and ECB
Key4 to 56 bytes

Frequently asked questions

Is Blowfish still recommended?

It remains useful for legacy compatibility, but its 64-bit block limits new designs. AES or ChaCha20-Poly1305 is generally preferred.

Why does CBC need an IV?

The IV makes the first block differ when the same key encrypts multiple messages. It should be unique and unpredictable for every encryption.

Is ECB secure?

ECB reveals repetition between identical blocks and should not protect structured data.