Level II Challenges (160)

Page 17 of the challenges in Level II, ordered by date posted (the most recent appear first).

Spirale — Part 3

[allard-03] - 4 users already solved this challenge.

Spirale is a OTP cipher designed to be simply performed by hand.
Part 3 is a ciphertext-only challenge with a 949-letter ciphertext.
In this part, two of the four keys are equal to the keys of the first two parts.

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Author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published on: 2015-08-23 19:08

Maximum number of attempts for this challenge: 15

All successful users of this challenge

User (#4)	Achieved points (Global score)	y-m-d - h:m:s

Scombes (jerva)	1378 (266541)	2015-09-13 15:43:29
J-L Morel (Rossignol)	1143 (42130)	2017-01-19 15:27:30
George Lasry (george4096)	1129 (422251)	2017-08-21 21:46:21
D3d4lu5 (D3d4lu5)	1098 (363488)	2021-01-19 19:45:17

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Spirale — Part 2

[allard-02] - 5 users already solved this challenge.

Spirale is a OTP cipher designed to be simply performed by hand.
Part 2 is a ciphertext-only challenge with a 659-letter ciphertext.
This part uses the same four keys for encryption as part 1 does.

Click here to get to the corresponding forum topic to share your opinion.

Click here to download the challenge.

Click here to download the additional file of the challenge.

Author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published on: 2015-08-23 19:05

Maximum number of attempts for this challenge: 15

All successful users of this challenge

Rank	User (#5)	Achieved points (Global score)	y-m-d - h:m:s

	Scombes (jerva)	1378 (266541)	2015-09-12 21:15:06
	J-L Morel (Rossignol)	1143 (42130)	2017-01-19 15:23:12
	George Lasry (george4096)	1129 (422251)	2017-08-21 21:06:46
	Kurt Gebauer (Yokozuna)	1103 (282608)	2020-01-28 12:25:55
#5	D3d4lu5 (D3d4lu5)	1098 (363488)	2021-01-19 19:44:01

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Spirale — Part 1

[allard-01] - 5 users already solved this challenge, 2 are working on it.

Spirale is a OTP cipher designed to be simple to implement by hand. It is resilient to errors as they have only a local effect without obscuring all the ciphertext.
Part 1 is a partly-known plaintext challenge with a 314-letter ciphertext. The first 75 letters of the plaintext are known.
Part 2 of this series uses the same four keys as this one.

Click here to get to the corresponding forum topic to share your opinion.

Click here to download the challenge.

Click here to download the additional file of the challenge.

Author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published on: 2015-08-23 19:04

Maximum number of attempts for this challenge: 15

All successful users of this challenge

Rank	User (#5)	Achieved points (Global score)	y-m-d - h:m:s

	Scombes (jerva)	1378 (266541)	2015-09-12 21:12:42
	J-L Morel (Rossignol)	1143 (42130)	2017-01-19 15:14:20
	George Lasry (george4096)	1129 (422251)	2017-08-21 20:56:27
	Kurt Gebauer (Yokozuna)	1103 (282608)	2020-01-28 12:24:14
#5	D3d4lu5 (D3d4lu5)	1098 (363488)	2021-01-19 19:42:42

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Flawed Usage of a OTP Cipher by the BND

[drobick-04] - 15 users already solved this challenge.

During the cold war the foreign intelligence agency of Germany established so-called stay-behind units. Their radio messages were encrypted by a OTP method, but the keys were used multiple times.
This challenge is about the effect of this multiple usage on the security of the method. You are given 5 messages, all encrypted with the same key.

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Author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published on: 2015-08-23 19:00

Maximum number of attempts for this challenge: 15

All successful users of this challenge

Rank	User (#15)	Achieved points (Global score)	y-m-d - h:m:s

	Armin Krauss (argh)	1725 (206965)	2015-08-26 17:13:36
	Kurt Gebauer (Yokozuna)	1576 (282608)	2015-08-28 22:20:36
	Alain (Integral)	1456 (207924)	2015-09-04 16:37:12
	Bart den Hartog (Bart13)	1398 (149236)	2015-09-10 14:30:56
#5	Julia Bernotat (El Greco )	1337 (81129)	2015-09-21 21:32:23
#6	Robert (rm)	1292 (56475)	2015-10-08 21:06:29
#7	Matthias Kotzerke (Esdeath)	1182 (4004)	2016-03-30 19:45:17
#8	Em Doulgerakis (Greko)	1172 (193799)	2016-05-16 09:35:38
#9	Alain Collignon (vexilla72)	1152 (123666)	2016-10-10 18:28:06
#10	D3d4lu5 (D3d4lu5)	1130 (363488)	2017-08-08 22:49:04
#11	Nicolas (nicosPavlov)	1120 (257791)	2018-04-01 11:44:13
#12	Dominik M. (Sgt. Pepper)	1117 (128575)	2018-06-21 23:00:27
#13	Eugene (lim0n)	1106 (195334)	2019-09-28 17:08:21
#14	Polaris (Polaris)	1100 (32963)	2020-08-16 17:37:58
#15	Eric (ExAstris)	1096 (56037)	2021-06-24 02:19:58

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Double-Column Transposition/Granit — Part 3

[drobick-03] - 0 users already solved this challenge.

This challenge series is about the GRANIT cipher, a method that can be done manually. It has been used for instance by the former GDR spy Günter Guillaume till about 1960.
Part 1, 2 and 3 of this series use the same keyword for generating the key matrix, but different permutation keys. This part has a ciphertext-only challenge and the ciphertext has 80 characters.

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Author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published on: 2015-07-01 18:23

Maximum number of attempts for this challenge: 10

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