Service - Hash length extension attack

30 Points  0x0

H(key ∥ message)

Author

koma,  

Level  Difficulty

Validations

1281 Challengers 1%

Note  Notation

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78 Votes

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solutions 1 Solution

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Challenge Results Challenge Results

Pseudo Challenge Lang Date
jeanchpt Cryptanalyse  Service - Hash length extension attack fr 13 April 2026 at 21:17
alibaba Cryptanalyse  Service - Hash length extension attack fr 12 April 2026 at 17:26
kern_keeper Cryptanalyse  Service - Hash length extension attack fr 11 April 2026 at 03:41
yohboy Cryptanalysis  Service - Hash length extension attack en 10 April 2026 at 19:48
Wolfy03479 Cryptanalyse  Service - Hash length extension attack fr 5 April 2026 at 14:44
Hawkyard Cryptanalyse  Service - Hash length extension attack fr 31 March 2026 at 20:14
YokonoxX Cryptanalyse  Service - Hash length extension attack fr 30 March 2026 at 16:21
Mateo Cryptanalyse  Service - Hash length extension attack fr 30 March 2026 at 14:53
Zizou Cryptanalyse  Service - Hash length extension attack fr 30 March 2026 at 14:47
Panacota Cryptanalysis  Service - Hash length extension attack en 28 March 2026 at 02:32

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% 98068 5 Xartrick 10 4 December 2012
pas_valide Encoding - UU 20% 75144 5 g0uZ 10 7 October 2006
pas_valide Hash - DCC 3% 10259 5 Podalirius 1 13 July 2021
pas_valide Hash - DCC2 3% 9346 5 Podalirius 1 13 July 2021
pas_valide Hash - LM 3% 9796 5 Podalirius 2 13 July 2021
pas_valide Hash - Message Digest 5 17% 64715 5 g0uZ 7 31 January 2010
pas_valide Hash - NT 3% 7980 5 Podalirius 2 13 July 2021
pas_valide Hash - SHA-2 9% 34295 5 koma 4 3 June 2012
pas_valide Shift cipher 6% 22377 10 m31z0nyx 10 16 February 2011
pas_valide CISCO - Salted Password 2% 6489 10 Tidusrose 3 13 July 2021
pas_valide Pixel Madness 5% 17289 15 Ryscrow 10 3 February 2011
pas_valide ELF64 - PID encryption 3% 8623 15 Lu33Y 10 8 February 2012
pas_valide File - PKZIP 4% 14274 15 g0uZ 6 30 August 2010
pas_valide Monoalphabetic substitution - Caesar 5% 18171 15 Arod 5 22 October 2011
pas_valide Circular Bit Shift 1% 2253 20 BlackRaven 3 21 March 2023
pas_valide Known plaintext - XOR 3% 10043 20 Ryscrow 5 3 February 2011
pas_valide Code - Pseudo Random Number Generator 2% 4074 20 Tosh 6 19 December 2012
pas_valide Encoding - Codebook 1% 615 20 n3rada 1 21 March 2023
pas_valide File - PKZIP 2 1% 591 20 kevin.mille 2 8 November 2024
pas_valide File - Insecure storage 1 3% 9805 20 g0uZ 7 6 February 2012
pas_valide Polyalphabetic substitution - Vigenère 3% 11177 20 Arod 3 26 October 2011
pas_valide System - Android lock pattern 2% 7370 20 Silentd 5 23 December 2012
pas_valide Transposition - Rail Fence 2% 6982 20 YellowS4 4 6 April 2014
pas_valide AES - CBC - Bit-Flipping Attack 1% 1808 25 Tie21 5 17 June 2018
pas_valide AES - ECB 1% 2976 25 cez40 4 29 November 2015
pas_valide AES - ECB - Copy Paste 1% 484 25 Vozec 1 5 February 2024
pas_valide DSA - Implementation error 1% 210 25 Vozec 1 13 December 2024
pas_valide LFSR - Known plaintext 1% 1280 25 Brissouille 2 28 November 2017
pas_valide RSA - Factorisation 2% 5543 25 HacKSpider 5 12 September 2010
pas_valide RSA - Decipher Oracle 1% 2275 25 Zweisamkeit 4 11 May 2017
pas_valide Service - Timing attack 1% 3078 25 g0uZ , koma 5 28 October 2012
pas_valide Monoalphabetic substitution - Polybe 2% 4200 25 koma 6 6 December 2011
pas_valide Twisted secret 1% 638 25 NonStandardModel 2 14 August 2020
pas_valide Initialisation Vector 1% 2463 25 manticore , notfound404 6 25 August 2015
pas_valide Hill Cipher 1% 367 30 LetMeR00t 1 21 March 2023
pas_valide GEDEFU 1% 626 30 makhno 1 13 September 2016
pas_valide OTP - Implementation error 1% 596 30 Podalirius 3 22 March 2021
pas_valide RSA - Corrupted key 1 1% 539 30 blackndoor 2 28 November 2017
pas_valide RSA - Continued fractions 1% 1693 30 sambecks 1 8 September 2015
pas_valide RSA - Common modulus 1% 2255 30 franb 3 24 December 2016
pas_valide Service - Hash length extension attack 1% 1281 30 koma 1 19 August 2015
pas_valide Shamir Secret Sharing - Introduction 1% 494 30 Vozec 2 5 February 2024
pas_valide AES - 4 Rounds 1% 440 35 Cryptanalyse 0 5 September 2018
pas_valide ECDSA - Introduction 1% 425 35 Jrmbt 2 22 September 2019
pas_valide ElGamal - Fault attack (Introduction) 1% 117 35 Vozec 0 13 December 2024
pas_valide RSA - Padding 1% 360 35 Tosh 0 9 October 2016
pas_valide RSA - Signature 1% 278 35 sar 1 9 March 2020
pas_valide Shamir Secret Sharing - Traitor 1% 167 35 Vozec 1 5 February 2024
pas_valide AES128 - CTR 1% 846 40 Tosh 2 28 August 2015
pas_valide PHP - mt_rand 1% 216 40 NonStandardModel 0 28 March 2022
pas_valide Discrete logarithm problem 1% 1462 40 RFC4949 3 8 June 2014
pas_valide RSA - Corrupted key 2 1% 378 40 blackndoor 1 11 January 2018
pas_valide RSA - Corrupted key 3 1% 238 40 blackndoor 0 5 September 2019
pas_valide RSA - Multiple recipients 1% 1788 40 franb 4 29 November 2015
pas_valide AES - Fault attack #1 1% 259 50 Cryptanalyse 1 20 September 2018
pas_valide FEAL - Differential Cryptanalysis 1% 72 50 Tosh 1 28 March 2022
pas_valide Goldreich Goldwasser Halevi | Weak Parameter 1% 72 50 Vozec 0 13 December 2024
pas_valide Enigma Machine 1% 302 50 peyman 2 12 October 2016
pas_valide Side Channel - AES : CPA 1% 152 50 cb34 0 28 March 2022
pas_valide ECDHE 1% 300 60 Tosh 2 20 November 2016
pas_valide NTRU | Multiple Transmission 1% 70 60 Vozec 0 13 December 2024
pas_valide NTRU | Weak Parameter 1% 63 60 Vozec 0 13 December 2024
pas_valide RSA - H-rabin 1% 137 60 Vozec 0 21 March 2023
pas_valide RSA - Lee cooper 1% 210 60 blackndoor , Synacktiv 1 7 November 2019
pas_valide Service - CBC Padding 1% 1482 60 koma 2 4 October 2012
pas_valide Side Channel - AES : first round 1% 163 60 walafc0 0 28 March 2022
pas_valide Polyalphabetic substitution - One Time Pad 1% 444 60 Thanat0s 0 2 June 2013
pas_valide White-Box Cryptography 1% 325 60 Cryptanalyse 3 21 October 2018
pas_valide AES - Weaker variant 1% 208 70 Cryptanalyse 1 29 August 2018
pas_valide Shamir Secret Sharing - Reduction 1% 114 70 Vozec 0 5 February 2024
pas_valide Hash - SHA-3 1% 241 75 Revenger 1 10 December 2016
pas_valide AES - Fault attack #2 1% 177 80 Cryptanalyse 1 20 September 2018
pas_valide Shamir Secret Sharing - Irreducible ? 1% 82 90 Mr7F 1 5 February 2024
pas_valide AES-PMAC 1% 70 100 Cryptanalyse 0 26 May 2019
pas_valide ECDSA - Implementation error 1% 100 100 Tosh 0 29 September 2019