Service - Hash length extension attack

30 Points  0x0

H(key ∥ message)

Author

koma,  

Level  Difficulty

Validations

1194 Challengers 1%

Note  Notation

1
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5
78 Votes

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solutions 1 Solution

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Challenge Results Challenge Results

Pseudo Challenge Lang Date
luk0t Cryptanalyse  Service - Hash length extension attack fr 23 July 2025 at 01:31
Vorstag Cryptanalyse  Service - Hash length extension attack fr 15 July 2025 at 09:22
DAlexis12 Cryptanalyse  Service - Hash length extension attack fr 3 July 2025 at 19:28
bylal Cryptanalyse  Service - Hash length extension attack fr 30 June 2025 at 02:59
AlexsB Cryptanalyse  Service - Hash length extension attack fr 28 June 2025 at 23:09
celi Cryptanalyse  Service - Hash length extension attack fr 24 June 2025 at 19:51
Munto Cryptanalyse  Service - Hash length extension attack fr 16 June 2025 at 01:52
Adem0 Cryptanalyse  Service - Hash length extension attack fr 6 June 2025 at 17:08
4ck3rm4n Cryptanalysis  Service - Hash length extension attack en 4 June 2025 at 03:28
Graulito Cryptanalyse  Service - Hash length extension attack fr 16 May 2025 at 22:50

challenges 75 Challenges

Results Name Validations Number of points  Explanation for the scores Difficulty  Difficulty Author Note  Notation Solution Date
pas_valide Encoding - ASCII 26% 92831 5 Xartrick 10 4 December 2012
pas_valide Encoding - UU 20% 71431 5 g0uZ 10 7 October 2006
pas_valide Hash - DCC 3% 8857 5 Podalirius 1 13 July 2021
pas_valide Hash - DCC2 3% 8139 5 Podalirius 1 13 July 2021
pas_valide Hash - LM 3% 8603 5 Podalirius 2 13 July 2021
pas_valide Hash - Message Digest 5 17% 62326 5 g0uZ 7 31 January 2010
pas_valide Hash - NT 2% 6944 5 Podalirius 2 13 July 2021
pas_valide Hash - SHA-2 9% 32932 5 koma 4 3 June 2012
pas_valide Shift cipher 6% 21180 10 m31z0nyx 10 16 February 2011
pas_valide CISCO - Salted Password 2% 5616 10 Tidusrose 3 13 July 2021
pas_valide Pixel Madness 5% 16439 15 Ryscrow 10 3 February 2011
pas_valide ELF64 - PID encryption 3% 8183 15 Lu33Y 10 8 February 2012
pas_valide File - PKZIP 4% 13461 15 g0uZ 6 30 August 2010
pas_valide Monoalphabetic substitution - Caesar 5% 16967 15 Arod 5 22 October 2011
pas_valide Circular Bit Shift 1% 1751 20 BlackRaven 3 21 March 2023
pas_valide Known plaintext - XOR 3% 9486 20 Ryscrow 5 3 February 2011
pas_valide Code - Pseudo Random Number Generator 2% 3724 20 Tosh 6 19 December 2012
pas_valide Encoding - Codebook 1% 454 20 n3rada 1 21 March 2023
pas_valide File - PKZIP 2 1% 346 20 kevin.mille 2 8 November 2024
pas_valide File - Insecure storage 1 3% 9455 20 g0uZ 7 6 February 2012
pas_valide Polyalphabetic substitution - Vigenère 3% 10655 20 Arod 3 26 October 2011
pas_valide System - Android lock pattern 2% 7073 20 Silentd 5 23 December 2012
pas_valide Transposition - Rail Fence 2% 6661 20 YellowS4 4 6 April 2014
pas_valide AES - CBC - Bit-Flipping Attack 1% 1693 25 Tie21 5 17 June 2018
pas_valide AES - ECB 1% 2761 25 cez40 4 29 November 2015
pas_valide AES - ECB - Copy Paste 1% 347 25 Vozec 1 5 February 2024
pas_valide DSA - Implementation error 1% 73 25 Vozec 1 13 December 2024
pas_valide LFSR - Known plaintext 1% 1094 25 Brissouille 2 28 November 2017
pas_valide RSA - Factorisation 2% 5118 25 HacKSpider 5 12 September 2010
pas_valide RSA - Decipher Oracle 1% 2094 25 Zweisamkeit 4 11 May 2017
pas_valide Service - Timing attack 1% 2943 25 g0uZ , koma 5 28 October 2012
pas_valide Monoalphabetic substitution - Polybe 2% 3997 25 koma 6 6 December 2011
pas_valide Twisted secret 1% 529 25 NonStandardModel 2 14 August 2020
pas_valide Initialisation Vector 1% 2307 25 manticore , notfound404 6 25 August 2015
pas_valide Hill Cipher 1% 230 30 LetMeR00t 1 21 March 2023
pas_valide GEDEFU 1% 581 30 makhno 1 13 September 2016
pas_valide OTP - Implementation error 1% 487 30 Podalirius 3 22 March 2021
pas_valide RSA - Corrupted key 1 1% 457 30 blackndoor 2 28 November 2017
pas_valide RSA - Continued fractions 1% 1522 30 sambecks 1 8 September 2015
pas_valide RSA - Common modulus 1% 2080 30 franb 3 24 December 2016
pas_valide Service - Hash length extension attack 1% 1194 30 koma 1 19 August 2015
pas_valide Shamir Secret Sharing - Introduction 1% 362 30 Vozec 1 5 February 2024
pas_valide AES - 4 Rounds 1% 367 35 Cryptanalyse 0 5 September 2018
pas_valide ECDSA - Introduction 1% 342 35 Jrmbt 2 22 September 2019
pas_valide ElGamal - Fault attack (Introduction) 1% 38 35 Vozec 0 13 December 2024
pas_valide RSA - Padding 1% 298 35 Tosh 0 9 October 2016
pas_valide RSA - Signature 1% 212 35 sar 1 9 March 2020
pas_valide Shamir Secret Sharing - Traitor 1% 104 35 Vozec 1 5 February 2024
pas_valide AES128 - CTR 1% 738 40 Tosh 2 28 August 2015
pas_valide PHP - mt_rand 1% 176 40 NonStandardModel 0 28 March 2022
pas_valide Discrete logarithm problem 1% 1334 40 RFC4949 3 8 June 2014
pas_valide RSA - Corrupted key 2 1% 333 40 blackndoor 1 11 January 2018
pas_valide RSA - Corrupted key 3 1% 197 40 blackndoor 0 5 September 2019
pas_valide RSA - Multiple recipients 1% 1665 40 franb 4 29 November 2015
pas_valide AES - Fault attack #1 1% 205 50 Cryptanalyse 1 20 September 2018
pas_valide FEAL - Differential Cryptanalysis 1% 51 50 Tosh 0 28 March 2022
pas_valide Goldreich Goldwasser Halevi | Weak Parameter 1% 21 50 Vozec 0 13 December 2024
pas_valide Enigma Machine 1% 276 50 peyman 2 12 October 2016
pas_valide Side Channel - AES : CPA 1% 91 50 cb34 0 28 March 2022
pas_valide ECDHE 1% 246 60 Tosh 2 20 November 2016
pas_valide NTRU | Multiple Transmission 1% 29 60 Vozec 0 13 December 2024
pas_valide NTRU | Weak Parameter 1% 21 60 Vozec 0 13 December 2024
pas_valide RSA - H-rabin 1% 91 60 Vozec 0 21 March 2023
pas_valide RSA - Lee cooper 1% 170 60 blackndoor , Synacktiv 1 7 November 2019
pas_valide Service - CBC Padding 1% 1384 60 koma 2 4 October 2012
pas_valide Side Channel - AES : first round 1% 94 60 walafc0 0 28 March 2022
pas_valide Polyalphabetic substitution - One Time Pad 1% 386 60 Thanat0s 0 2 June 2013
pas_valide White-Box Cryptography 1% 254 60 Cryptanalyse 3 21 October 2018
pas_valide AES - Weaker variant 1% 151 70 Cryptanalyse 1 29 August 2018
pas_valide Shamir Secret Sharing - Reduction 1% 51 70 Vozec 0 5 February 2024
pas_valide Hash - SHA-3 1% 164 75 Revenger 1 10 December 2016
pas_valide AES - Fault attack #2 1% 147 80 Cryptanalyse 1 20 September 2018
pas_valide Shamir Secret Sharing - Irreducible ? 1% 35 90 Mister7F 0 5 February 2024
pas_valide AES-PMAC 1% 40 100 Cryptanalyse 0 26 May 2019
pas_valide ECDSA - Implementation error 1% 69 100 Tosh 0 29 September 2019