[Cryptography] Which big-name ciphers have been broken in living memory?

[Bear]

On Tue, 2014-08-26 at 23:24 +1200, Peter Gutmann wrote:
> Bear <bear at sonic.net> writes:
> 
> >Is there any evidence that CAST5 is in any way inadequate?
> >
> >People are upset with use of an "Antique" algorithm?  Why?
> 
> There's nothing obviously wrong with CAST, but it is nearly twenty years old
> and hasn't had anywhere near the analysis of AES (or 3DES), particularly
> against recent cryptanalysis techniques.  

(Massive snip)

See, those are much better reasons for proposing a change.  
When someone wants to change and advances no better reason 
than "It's Old," or "it's an antique from the 90's" or such
that doesn't make sense.  Math doesn't go stale. "Old" just 
means that it has remained in place with no discovered 
weaknesses through more cryptanalytic effort, and ought 
therefore be considered more, rather than less, reliable. 

But when you come out and admit that cryptanalysts, 
especially those using more modern methods and attacks, 
have been actively ignoring it such that it has now withstood 
LESS cryptanalytic effort than some more recent cipher, that 
makes a bit less nonsense.  The problem is not its age, 
the problem is that despite it having been around for more 
cryptanalytic effort it has actually withstood less. 

The 64-bit blocksize being too short is also a legitimate 
technical issue and a good reason for requesting a change, 
especially when use for file encryption offers so many 64-bit 
blocks whose contents are completely known to an attacker.  


Bear