Re: Silly beginner questions



Sebastian Gottschalk <seppi@xxxxxxxxx> writes:

Unruh wrote:

??? RSA had no limit on the length of the composite when it was invented.
At that time they thought that 129 bits was fine, but that was no limit.
And sure I would use 56 bit DES. I would use it three times-- with
different keys.
AES with a 2 bit key is hopelessly unsecure. Does that mean that AES is
insecure? That AES can be broken by current computers? No.
Similarly neither RSA not DES ( with a longer key eg triple des) are broken.

IBTD. DES has a block size of 64 bits, thus after about 32 GByte of data
there's one block collision to be expected.

Yes. And so? What is that going to do for you?


And limititations on DES are an interesting worry. Current analysis tell
that even if you'd freely choose all round subkeys of DES independently
(thus implying a key size of 768 bits), you'd still end up with an
effective security of about 64 bit.

???
You are not saying that say triple DES has an effective key size of 64
bits, are you?

The claim was that with current computers ANY cypher more than 30 years old
was broken.
Neither are. (Note, neither is OTP which is much much older than 30 years
old)


.



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