1) Experts in all fields are always wrong sometimes. The nonexperts are wrong more frequently on average and people are less interested in proving them wrong.

2) Saying that implementing your own cryptography usually implies a production environment. I think it's generally assumed that nobody cares what people do with their own time/personal projects.

3) Trite sounds bites don't work in science either, and expert -/-> celebrity.

Ad 2) most groundbreaking projects you know originated as messy ad-hoc personal projects and not in production-sanitized environments (look even at GPG, embarrassingly for crypto community with one almost bankrupt developer). Crypto-logy/graphy is an art, someone has a bright idea while lacking in other dimensions; the crypto community instead of embracing this idea and helping this person to bring something excellent to the world, shoots them instead down and point to obvious flaws that can be fixed in minutes by someone experienced, while keeping the new idea intact. The crypto requires such an enormous amount of talent that it is bright individuals, not companies, that make things move there, and quite often the more people involved, the worse results.

> someone has a bright idea while lacking in other dimensions; the crypto community instead of embracing this idea and helping this person to bring something excellent to the world, shoots them instead down

I'm sorry, but this is essentially never the case. This is no different than in other fields, for instance math or physics, where complete novices come in every day believing they've had a completely novel idea that will revolutionize the field. 999,999 times out of a million they haven't, and in the one remaining case they've come up with a solution in search of a problem.

"Oh, you've come up with a new cipher? Congratulations. Assuming it is secure, why should we use it ? Is it faster than existing ones? Simpler and more likely to be implemented correctly? Resistant to timing attacks? Resistant to CPU power analysis? Resistant to differential cryptanalysis? Suitable for low-CPU and low-memory embedded devices? Oh, none of these things? Gee, how interesting."

I'm reminded of http://www.scottaaronson.com/blog/?p=304

> Crypto-logy/graphy is an art, someone has a bright idea while lacking in other dimensions; the crypto community instead of embracing this idea and helping this person to bring something excellent to the world, shoots them instead down and point to obvious flaws that can be fixed in minutes by someone experienced, while keeping the new idea intact.

Crypto is an environment where a single mistake can get people killed. The stakes are very high. We're not talking about a slight rendering error in CSS here. This is not an appropriate place to be universally warm, fuzzy, encouraging, and forgiving of mistakes. This is incredibly serious stuff that must be treated appropriately seriously - and everyone attempting to touch the field needs to understand that.

In addition, stouset is right. The frequency with which apparently novel ideas are actually novel is much, much, much smaller than a naive guess would lead one to expect. I've watched people attempt to introduce ideas that strike them as novel, only to discover that they're just creating exploitable weaknesses, right here on Hacker News.