# David Stein, "The Puzzle at CIA Headquarters: Cracking the Courtyard Crypto" (Studies in Intelligence, 1999)

> The CIA analyst's own account of solving K1 to K3 by hand over about 400 hours from 1991 to 1998, with the plaintexts; written for the agency's internal…

Source: https://mysteriesdept.com/mysteries/kryptos/artifacts/ART0D7HTJSP0MDA/david-stein-the-puzzle-at-cia-headquarters-cracking-the  
Publisher: Mysteries Department  
Licence: CC BY 4.0 (credit Mysteries Department and link the page)  

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[Mysteries](https://mysteriesdept.com/mysteries)[Kryptos](https://mysteriesdept.com/mysteries/kryptos)[Artifacts](https://mysteriesdept.com/mysteries/kryptos#artifacts)David Stein, "The Puzzle at CIA Headquarters: Cracking the Courtyard Crypto" (Studies in Intelligence, 1999)

**ART** 0D7HTJSP0MDA·Artifact · document

# David Stein, "The Puzzle at CIA Headquarters: Cracking the Courtyard Crypto" (Studies in Intelligence, 1999)

Document11 pagesPublic domainPublished 1999 in the CIA's internal journal

[Cite][Download](https://mysteriesdept.com/files/d/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0)

[Pages][Text]Page 1 of 11

[![Page 1](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p1)1][![Page 2](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p2)2][![Page 3](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p3)3][![Page 4](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p4)4][![Page 5](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p5)5][![Page 6](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p6)6][![Page 7](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p7)7][![Page 8](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p8)8][![Page 9](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p9)9][![Page 10](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p10)10][![Page 11](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p11)11]

![Page 1 of David Stein, "The Puzzle at CIA Headquarters: Cracking the Courtyard Crypto" (Studies in Intelligence, 1999)](https://mysteriesdept.com/files/v/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0/p1)

Text taken from the file. Check it against the page.

The CIA analyst's own account of solving K1 to K3 by hand over about 400 hours from 1991 to 1998, with the plaintexts; written for the agency's internal journal and later declassified.

Central Intelligence Agency (declassified release), 1999. Public domain

## Copies 2

**Scan** Central Intelligence Agency (declassified release) · nsarchive2.gwu.edu · Public domain (US government work)Primary source: [The Puzzle at CIA Headquarters: Cracking the Courtyard Crypto](https://mysteriesdept.com/sources/SRC0D7HSVVA2G5B/the-puzzle-at-cia-headquarters-cracking-the-courtyard-crypto)1 step from the original

[Where it's published](https://nsarchive2.gwu.edu/NSAEBB/NSAEBB431/docs/intell_ebb_010.PDF)[Download](https://mysteriesdept.com/files/d/13ac4582602318b4cdb7a3b6931dab9708904e7d06e417d1eb33182619c44db0)

**Cracking the courtyard crypto" (studies in…** David D. Stein, Central Intelligence Agency · nsarchive2.gwu.edu · Public domain (US government work)1 step from the original

[Where it's published](https://nsarchive2.gwu.edu/NSAEBB/NSAEBB431/docs/intell_ebb_010.PDF)

## Where it was made

[Courtyard of CIA headquarters, Langley](https://mysteriesdept.com/records/PLC0D7HT1764VQ3/courtyard-of-cia-headquarters-langley) · Building courtyard

## Sources 1

- [The Puzzle at CIA Headquarters: Cracking the Courtyard Crypto](https://mysteriesdept.com/sources/SRC0D7HSVVA2G5B/the-puzzle-at-cia-headquarters-cracking-the-courtyard-crypto)_SRC_

## Cite it

```
Mysteries Department. (2026). David Stein, "The Puzzle at CIA Headquarters: Cracking the Courtyard Crypto" (Studies in Intelligence, 1999) [Artifact ART0D7HTJSP0MDA]. https://mysteriesdept.com/r/ART0D7HTJSP0MDA
```

Key

**ART** 0D7HTJSP0MDA

Kind

Document

Held by

Central Intelligence Agency; released copy posted by the National Security Archive

Dated

published 1999 in the CIA's internal journal

Licence

Public domain (US government work)

Place

[Courtyard of CIA headquarters, Langley](https://mysteriesdept.com/records/PLC0D7HT1764VQ3/courtyard-of-cia-headquarters-langley)

Part of

[Kryptos](https://mysteriesdept.com/mysteries/kryptos)

The record

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