Re: Newbie data size encryption questions
JG wrote:
If I use a symmetric cipher like DES or 3DES, what is the minimum
amount of data that I can encrypt without the system being insecure?
For example, if i wanted to encrypts strings of say 5 or 10 characters,
is there a security problem here? Is there a problem if the first few
characters (or others) of the string are sometimes the same?
Are there any general principles w.r.t. encryption of small amounts of
data using ymmetric keys?
Only problem is any secure mode you want to use will probably need
extra storage. LRW would expand it to the size of the cipher [e.g. 16
bytes for AES] and other modes like CTR would need an IV.
If you can avoid encrypting only single strings per session you can
mitigate the overhead by having an IV per block of strings, etc, etc.
Eitherway don't use DES or 3DES. AES is faster, more standard and
easier to use (since you don't need 3-key mode to get decent security).
Tom
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