Why is Blowfish's key size limited to 128 bits in RFC 4880?

Dieter Frye includestdioh at secmail.pro
Sat Oct 10 12:00:56 CEST 2020

>> What's the rationale behind not going full 448 or at least 256 like
>> AES and Twofish?
> Age.  At the time Blowfish was adopted there were literally no 256-bit
> ciphers in the RFC2440 suite.  Symmetric ciphers were all 128-bit
> (except arguably for 3DES, where the size is wonky[*]).  The first
> 256-bit cipher to be added was Twofish in mid-2000 in PGP 7, followed
> soon by AES in PGP 7.1.
> [*] 3DES can credibly be claimed to have a 192-bit key, a 168-bit key,
> or a 112-bit key, depending on how the speaker defines "key".
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Thanks, I appreciate the quick response.

I've been using Blowfish on older machines for years now without issue and
I always wondered if this is one of those things that could possibly
benefit from an update.

Best regards.

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