Why Johnny Can't Encrypt: A Usability Evaluation of PGP 5.0
1999 · paper · Computer science
A usability study of the email encryption program PGP 5.0, using an expert walkthrough and a laboratory test with novices. Most participants could not sign and encrypt a message within 90 minutes, which the authors take as evidence that security needs its own usability standard.
Checked: PDF from usenix.org, fetched 4 Oct 2026. Page numbers are those of that PDF.
0 findings
None that passed a second check.
3 minor (typos and the like; most checked by the judge only)
Typo Misspelling on p.5, Section 3: "as a cognitive walkthough" should be "walkthrough".
- p. 5 Section 3, right column, second paragraph
as a cognitive walkthough, it also incorporated aspects
- p. 5 Section 3, third paragraph
as a cognitive walkthough
- p. 5 Section 3, para 3
cognitive walkthough
Judge's note: The page-5 crop shows "cognitive walkthough" in the typeset text, so this is not an extraction artefact. Elsewhere in the paper (e.g. the same column, "cognitive walkthrough tends to") the word is spelled correctly.
Second check: none (judge only)
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Typo Duplicated word on p.13: "sent email to the the entire team encrypted only with that key".
- p. 13 Section 5.3, 'Figuring out the correct key to encrypt with', left column
sent email to the the entire team encrypted
- p. 13 Section 5.3, Figuring out the correct key to encrypt with
sent email to the the entire team
- p. 13 Figuring out the correct key to encrypt with
email to the the entire team
- p. 13
c key, but then sent email to the the entire team encrypt
Judge's note: The page-13 crop shows "the the" on a single typeset line, so it is not caused by a line break or by extraction.
Second check: code check
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Typo Reference 17 (p.16) prints the title as "The Cognitive Walkthrough Method: A Practioner's Guide"; "Practioner's" should be "Practitioner's".
- p. 16 References, entry 17
Method: A Practioner’s Guide.
- p. 16 Reference 17
A Practioner’s Guide
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: the published chapter title spells the word "Practitioner's". The page-16 crop confirms that "Practioner's" is in the typeset reference list, and "Practioner" is not an English word.
Second check: none (judge only)