Yes, this is my concern too. However, anyone who posts to a newsgroup saying “I’m about to write my own cipher, any advice” should not do it. The post indicated someone who planned to actually start writing code; that’s a definite sign that they shouldn’t do it.
Even though it’s unlikely to work, it is still the approach which minimizes risk; even a small reduction in their probability of going ahead will likely be a bigger effect than any other safety advice you can give, and any other advice will act against its efficacy.
Yes, this is my concern too. However, anyone who posts to a newsgroup saying “I’m about to write my own cipher, any advice” should not do it. The post indicated someone who planned to actually start writing code; that’s a definite sign that they shouldn’t do it.
See the addendum above; “don’t do it” isn’t likely to work.
Even though it’s unlikely to work, it is still the approach which minimizes risk; even a small reduction in their probability of going ahead will likely be a bigger effect than any other safety advice you can give, and any other advice will act against its efficacy.