Is it legal to forcefully asking trade secrete during interview?

Recently I have an interview with a company that is desperately wanted to penetrate business with my concurrent company. During Interview, a VP of RD consistently asked for technology trade secret of my current company. Soon after, I've told him many times that I don't feel comfortable being asked about detail on non public technology trade secrete of my current company and asked that he either change the topic or stay at higher level discussion in interview. However, this VP of RD elaborated that it is important and critical for him to get from me the "details", and I refused again and almost wanted to walk away from the remaining of interview. After all, he should be focusing on my ability and track record to support his company in which I am interviewing for and not push for trade secret to gain leverage to the business. Interview was done; however, I would like to get advise if there is legal issue with this, and I am very certain this company might have used this type of interview opportunities to gain ground in technology. Thanks. - Someone