Table of Content

Cybersecurity Frameworks

Key Management Interoperability Protocol

What is Blowfish in security? Who uses Blowfish?


Blowfish, a symmetric-key block cipher, emerged on the cryptographic scene in 1993 through the efforts of Bruce Schneier. This algorithm was designed to be a versatile, secure, and swift alternative to existing encryption methods. Notably, Schneier’s philosophy behind Blowfish was groundbreaking for its time – he made the algorithm unpatented and freely available to the public. This openness contributed significantly to Blowfish’s widespread adoption in diverse applications and systems. 


  • Key Change Impact on Speed

    Changing keys in Blowfish can negatively impact speed. This limitation could be a concern when frequent key changes are required.

  • Lengthy Key Schedule

    The key schedule process in Blowfish takes considerable time. This can be a drawback, especially when a quick key setup is essential.

  • Vulnerability to Brute-force Attacks

    Blowfish’s small 64-bit block size makes it susceptible to a class of brute-force attacks. The collision probability (two different inputs producing the same output) increases with the limited block size, potentially compromising security.

  • Resource-Intensive Key Preprocessing

    Introducing a new key in Blowfish requires preprocessing equivalent to 4 KB of text. This preprocessing level, especially for each new key, can impact the speed and efficiency of the algorithm, making it less suitable for certain applications.

In response to these concerns, Bruce Schneier and other cryptography experts developed Twofish as a successor to Blowfish. Twofish participated in the AES competition held by the National Institute of Standards and Technology (NIST) to determine the Advanced Encryption Standard (AES). 

Despite not being chosen as the AES, Blowfish has left an indelible mark on cryptographic history. Its legacy persists, and it continues to find application in various contexts. While not considered state-of-the-art today, the historical significance of Blowfish remains notable within the broader narrative of cryptographic advancements. 

Advantages and Disadvantages

Advantages Disadvantages
Faster than other encryption algorithms, such as the Data Encryption Standard (DES) The key schedule of Blowfish takes a long time, equivalent to encrypting 4KBs of data, which can be a disadvantage or an advantage. On the Disadvantage side, it takes a very long time to do
Blowfish is unpatented and free to use. This means anyone can take and use Blowfish for whatever they want to The small block size of Blowfish means that Birthday Attacks can occur and compromise the encryption algorithm
The Blowfish algorithm also has a lesser amount of operations to complete compared to other encryption algorithms It is followed by Twofish, which was created to replace Blowfish, as it is better in most ways
The key schedule of Blowfish takes a long time, but this can be advantageous, as brute force attacks are more difficult

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