I'm looking for the name and author of a short story, probably in the 1980s or 1990s in one of the SF magazines, possibly Asimov's but I'm not sure about that.

A lawyer asks an undergraduate in biochemistry with an interest in cryptography to try to solve a cipher that was left by a murdered researcher. She was picked because her background was similar to the researcher. Though the researcher had a passing interest in cryptography, she had very little time to encipher her data before she was murdered. The lawyer thought someone with a similar background would be able to decode what she did.

The cipher is based on the three-letter codes for amino acids. There are 64 possible codes, which code for the various (I believe 20) amino acids. Some amino acids have two or more three-letter codes. You first need to translate the 64 three-letter codes into the amino acid they code for, then solve the 20 amino acids as a simple substitution cipher.

When the attorney for the other side says that there is no substitution for "x", she replies that "c-k-s" made an acceptable substitute.

  • Would you be able to weigh in on the discussion of the answer. Is the undergraduate the same as the pizza delivery girl below?
    – FuzzyBoots
    Mar 14, 2017 at 3:07
  • Yeah, that is something that confuses me. Is the undergrad merely disguised as a pizza delivery girl?
    – user64742
    Mar 14, 2017 at 17:22
  • The undergrad was disguised as a pizza girl in order to gain access to the courtroom so she could deliver the deciphered text. It was suggested by the person who asked her to decipher the text.
    – Yoshi Bro
    Mar 15, 2017 at 13:27

1 Answer 1


Harnessing Edlothiad's comment, this might be "The GUAC Bug" by Charles L. Harness.

Here is a plot summary:

Harness, Charles L. 1998. The GUAC Bug. Analog Science Fiction/Science Fact, 112-124.
Ms. Hatfield, the pizza delivery girl, decrypts a cipher built into an RNA specimen. The message is a double encipherment of an RNA sequence, where the nucleides (G, U, A, and C) define amino acids. Each of the 20 amino acids then represents a letter of the alphabet in a simple monoalphabetic substitution. The message is used in a patent hearing to verify the author and authenticity of the RNA specimen. The pizza delivery girl is used to show that the cipher message is easy enough for a knowledgeable amateur to solve.

I don't see any mention of murder, but it does involve coding by amino acids and has a relative amateur doing the decoding.

It looks like it was only ever released in Analog Science Fiction/Science Fact.

  • Thwarted! I was afraid I wouldn't be able to get more of a background.
    – Edlothiad
    Mar 13, 2017 at 12:05
  • @Edlothiad: :) Ah, well you hadn't followed up on it, and I figured it was a close enough match as it was.
    – FuzzyBoots
    Mar 13, 2017 at 12:06
  • As said by the great philosophers of old, You snooze, you lose
    – Edlothiad
    Mar 13, 2017 at 12:08
  • 1
    @The GreatDuck I never mentioned a murder investigation. The researcher was (fatally) injured in the burglary of her lab/office. She encrypted her research files. The two-step code exactly matches what I remember. Code from 64 amino acid combinations of biochemical coding for 20 amino acids-->code of 20 amino acids-->relatively easy substitution cipher. The "pizza girl" was a disguise to allow her to enter the courtroom (with the deciphered text in the pizza box) without her being named as an "expert witness". If she could decipher the text, there was obviously no need for an "expert".
    – Yoshi Bro
    Mar 14, 2017 at 6:38
  • 1
    @TheGreatDuck: We're starting to hit discussion levels in the comment thread, but in general, partial matches are encouraged on the site, both because the querent might have gotten it wrong and also because it provides a possible answer for people searching for similar works.
    – FuzzyBoots
    Mar 14, 2017 at 17:22

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