I read an SF novel about 30 years ago, where one of the characters is killed early, and the rest of the novel is his friends trying to decrypt what is on his personal device as they knew it was significant. At the end of the novel they find the right passcode / phrase, and find the plans for a massive SETI array that would be built (I think) between Jupiter and the asteroid belt. Really want to read this again as looking back it seemed quite visionary, but I haven't been able to find it.

Edit after reading "how to ask a good story-id question meta-post": Written in English. Most likely read this in 1970's or maybe early 80's. Based on Earth, future but not distant future. Standalone not anthology. Targeted at adult audience. Don't remember any of characters names. Have looked through lists of published works for all the leading authors and those I recall reading at the time (Clarke, Asimov, Heinlein, Niven, Greg Bear, Gregory Benford, Samuel Delany, Philip K Dick, Harlan Ellison, Philip Jose Farmer). I believe it was single author, not a collaboration.

  • In what sense were they trying to decrypt his PDA? Was the rest of the novel just them renting time on a super-computer and running hashes or was there more to it?
    – Valorum
    Jun 2, 2018 at 23:44
  • They had to try and guess his password / pass phrase, which they knew would be something significant to him. However it was one of those "3 guesses only" scenario, device would have destroyed the information after too many incorrect attempts Jun 2, 2018 at 23:46
  • I'm not seeing how this makes a novel. What are the things that they did in order to learn his passcode?
    – Valorum
    Jun 2, 2018 at 23:46
  • They were close friends and I think scientific colleagues, trying to get inside his mind, thinking about what he was working on and what was important to him Jun 2, 2018 at 23:48
  • So did they visit his workplace, read his emails, speak to his mother, ransack his apartment?
    – Valorum
    Jun 2, 2018 at 23:49

1 Answer 1


Imperial Earth by Arthur C. Clarke

Duncan Makenzie's best friend Karl Helmer unexpectedly dies. Duncan is given Karl's "minisec", which is a common device like an incredibly advanced palm top computer. Unfortunately it is password protected.

Duncan is visiting Earth to get himself cloned, and spends his spare time trying to guess the password.

When he does, he finds the plans for a SETI array using asteroids with a fuzz of kilometer long antennas

  • The bit with the minisec is on towards the end, after a whole lot of other stuff happens. Duncan doesn't spend his spare time during the entire trip trying to guess the password. Only a relatively short time (few days) after his friend Karl dies towards the end of the book.
    – JRE
    Jun 3, 2018 at 7:23
  • Duncan didn't have to guess the passwords. After the Earth government turned Karl's minisec over to him, Duncan got a list passwords from Karl's will from their home on Titan. He only had to guess whether or not to cancel an automatic delete function that might be present.
    – JRE
    Jun 3, 2018 at 7:46
  • The drawing of the SETI device was in a separate (paper) drawing pad. The explanation of how it should work was in the minisec. Along with speculations (by Karl) that the source of the signals might be as close as the Oort cloud.
    – JRE
    Jun 3, 2018 at 7:55
  • All that said, I expect this is the correct story.
    – JRE
    Jun 3, 2018 at 7:56
  • That certainly does look like the right story, even if my recollection of it seems a bit off. Probably explains why I didnt recognise this story when looking at other synopses on the web, as I was only recalling what seems to be a minor plot element. Will hunt out and re-read this! Thank you all Jun 3, 2018 at 8:59

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