The founder of bust bitcoin exchange Mt Gox took questions on Tether, the future of crypto, and losing 35kgs in prison - here are 6 things we learned

Karpeles was arrested in early 2015 by Japanese police investigating the collapse of Mt Gox and spent just under a year in jail before being bailed.

He said he "would not recommend" Japanese prison, joking that it had "poor service, bad food."

Karpeles said he "lost 35 kg in 4 months" in jail, adding: "I wouldn't recommend this to anyone."

"Lunch was actually two breads with jam (strawberry, orange, etc so there'd be some variation day to day) and a small extra," he wrote.

The case against Karpeles is still ongoing but he wrote: "I am innocent. Proving this in front of a Japanese court is a challenge but I'm not giving up."

Mt Gox's heyday coincided with Silk Road, the "dark web" marketplace for drugs, weapons, and more that used bitcoin as its main currency.

Silk Road was shut down by the FBI in October 2013 when its founder Ross William Ulbricht was arrested.

Karpeles was asked how big Silk Road's influence over Mt Gox's exchange was, as at the time it was the main exchange to buy and sell bitcoin on.

He wrote: "We didn't have an exact estimate, but following Ulbricht's arrest and shut down of silk road we noticed a drop in activity which allowed put a figure on that at around 20%~30%."

Ulbricht, who was 29 when he was arrested, was sentenced to life in jail for drug trafficking. Asked about the punishment, Karpeles wrote: "Evidence seems clear enough it was him, and there is, of course, a need to make an example of him as first ever such case, but it's sad for someone that young to have to spend life behind bars."

Karpeles was also asked about what Mt Gox did to stop child traffickers who accepted bitcoin through sites such as Backpage.com.

"MtGox cooperated as much as possible with law enforcement when presented with valid requests that did not infringe privacy of the MtGox userbase in general," he wrote.

Karpeles said he still believes in the potential of cryptocurrencies but said: "I can't say for sure if any of the existing crypto today will work out on the long term, but the technology is definitely here to stay, in one shape or another."

On bitcoin specifically, he wrote: "The technology is definitely here to stay, but Bitcoin may have trouble evolving and keeping up. This say [sic] I could be wrong about this. I've been wrong about a lot of things."

He added that after Mt Gox proceedings conclude he would like to go back to being a software engineer but not in the cryptocurrency space.

Asked if he would start or advise on an "initial coin offering" project, he said: "After the heat death of the universe, maybe."

The bitcoin community has been worrying about the growing influence of Tether, a cryptocurrency that is said to be backed one-for-one by the US dollar. Skeptics argue that the company behind it has not done enough to prove it has the dollar reserves it claims to.

Karpeles said: "I hear about Tether USDT a lot, and I believe more transparency would help greatly. The issue, rather than is Tether really in control of the assets it claims having, is will the US let Tether be or will they try to shut it down for helping money laundering/issuing money without license/etc.?

"I have no way to tell for sure. I do not think the US are really happy about Tether right now, and that might be exactly why US banks have blocked related transfers. When a third party bank starts blocking your transfers something really bad is going on."

Karpeles answered a range of other questions, raising from the serious to the whimsical.

Asked about Craig S. Wright, the Australian scientist who claimed to be the man behind mysterious bitcoin creator Satoshi Nakamoto, Karpeles wrote that Wright is "definitely not Satoshi as most "evidence" was a fraud."

The Mt Gox collapsed is rumoured to be being developed into a film and one Redditor asked Karpeles who he'd like to play himself in any movie adaptation.

"Jack Black," he wrote. "I really love the guy."

Karpeles was also asked about any regrets he had from the entire Mt Gox episode.

"When buying MtGox I should have had people around me to advise me and help with the management starting with the MtGox transfer contract," he wrote.

"I'm a tech guy, and bitcoin was a tech thing at the time. In April 2011 there was an article in Forbes which changed Bitcoin forever, and I found myself managing emergencies every day without any time to do the work that'd need to be actually done."

You can read the full Reddit thread here.