I have read about long message attacks on some cryptographic hash functions. However, I don't quite understand what is being referred to as a "long message".
Also, do long message attacks only apply for such "long" messages or can they also be used (any exceptions?) with "normal" messages? ("Normal" as opposed to "long", I mean)
EDIT: Actually, I thought I wanted a general explanation, but I guess it might be better that I specify the source of my misunderstanding. Reading Gauravaram and Kelsey's Cryptanalysis of a class of cryptographic hash functions in trying to understand second-preimage attacks, I came across the generic long message second preimage attack on GOST in Appendix Section E.1 (page 26) and it got me wondering on the meaning (and pertinence) of the so-called "long message" attack.
Hope this clarifies my question better.