1. Decryption of a file encrypted by pseudo-random number generator (The Linear Congruence rand()
  2. Successful Cryptanalysis Research/Attacks on Zero-Knowledge Proofs?

  3. Elliptic curve representation
  4. Will this Cryptosystem Works?

  5. How cryptographically secure was the original WW2 Enigma machine, from a modern viewpoint?

  6. help with ciphertext with no obvious key

  7. Cryptanalys of "bad" RC4 implementation

  8. UOV signature scheme, how does the affine transformation work? What does the composition of the core map and the affine map yield?

  9. A name for “word fingerprints” (technique for breaking monoalphabetic substitutional ciphers)

  10. Cracking stream cipher with IV
  11. How to break a columnar transposition cipher?
  12. Are there two known strings which have the same MD5 hash value?
  13. Using XL Algorithm to solve overdetermined systems, simple example required

  14. Developing algorithm for detecting plain text via frequency analysis

  15. Explaining why messages are vulnerable
  16. How can non-nothing-up-my-sleeve numbers be used to exploit an algorithm?

  17. What informal indicators exist for estimating the computational infeasibility of cryptographic problems?

  18. Breaking a XOR cipher of known key length

  19. Need an XL Algorithm example
  20. Basic attacks on McEliece; finding S and P
  21. Applicability of IBM's projected 50-qubit quantum computer Q to cryptanalysis?

  22. number of active s-boxes in a block cipher?
  23. Shanks's Babystep Giantstep Algorithm running time BigO
  24. Difference between one-level and two-level E0 encryption
  25. What is the best way to put a backdoor in an encryption system?
  26. Current day memory capabilities for cryptanalysis?
  27. Should the identity of a sender be verified using additional means, or does a MAC suffice?

  28. Does secure LWE implementation leak bit information?

  29. prove that the constructions are still PRF according to the definition

  30. Matsui's paper on linear cryptanalysis - unexplained formula in Lemma 2

  31. Playfair Cipher decryption
  32. Cryptanalysis - Brute force

  33. RC4: Find the complete plain text of a ciphertext when we know part of the plaintext

  34. Name of a Method

  35. How does a padding oracle attack work?
  36. What weak symmetric cryptographic algorithms shall I use to educate myself about cryptoanalysis methods?
  37. Key recovery after AES-ECB encryption of two blocks with some known plaintext/ciphertext
  38. Why is it inadvisable to increase the number of rounds or using a larger block size to a published(standardized) block cipher such as AES?
  39. How do I find the key of the Vigenere cipher is if I already know the key length?

  40. I think PBKDF2 may be better than Scrypt? Looking for someone to point out my logical error

  41. Determining linearity of a function using linear approximation table (LAT)

  42. Now that quantum computers have been out for a while, has RSA been cracked?

  43. Can I use a key twice if the message is longer than the key in one-time pad?

  44. Find the Special DES key
  45. Modifying an Enigma machine to allow unchanged letters
  46. Cryptography Basics
  47. Are there any tools for expressing the cipher operations as a system of equations?
  48. Why is the slide attack called a generic attack if it depends on each round being the same?
  49. Has any crypto hash function been proven to be surjective?

  50. Is rekeying attack the same as related-key attack?

  51. Using Keccak permutation as a block cipher
  52. Possible ways to crack simple hand ciphers?
  53. How to decode a caesar that goes to transposed plaintext?

  54. If you SHA something that already has work put into it, is it still safe?

  55. Is it right that the Bomba can halt, but give you a different settings other than the one Germans really used for encryption using an Enigma?
  56. Can it be proven that my home-brewed hash function is not LESS secure than a known good hash function it leverages?

  57. How to forge Schnorr signatures if you can guess the challenge

  58. Diffie-Hellman problem: is DH still secure if $g^{a^2}$ is known?
  59. AES-256 9 round related key attack - getting possible state differences

  60. What quality would an interactive proof executed many times sequentially have that makes it zero knowledge that one executed in parallel would not?
  61. Is 80 bits of key size considered safe against brute force attacks?

  62. Is Discrete Logarithmic assumption enough to design a secure searchable encryption scheme?

  63. Are 80-bit keys considered secure as of late-2017?
  64. Security implications of using hash as a MAC
  65. How can we add real values using GF field?

  66. Attacking a cipher, not knowing what the plaintext should look like – how do you know you’ve successfully decrypted the ciphertext?

  67. Is it possible to attack an SHA-256 hash seeded with PHP’s mt_rand function?
  68. Proof that this is not a secure pseudorandom function?

  69. How can I calculate non-linearity of an s-box element wise?

  70. Is it possible to assume that the adversary is not allowed to make an all zero plaintext query in IND-CPA?

  71. Is there a quick way to know the length of a message hashed using SHA3?
  72. Is it possible to actually verify a “sponge function” security claim?
  73. Analysis of Repeatedly Enciphered Plaintext using Same Algorithm / Key?

  74. Risks of full length KCV (components and full keys)?
  75. how to calculate the non linearity of each element of s box?

  76. What if we increase the key length of DES and use ECB Mode, then will we get the different output as ECB mode encrypt with the same key?

  77. Cryptanalysis on block cipher (What is exactly a zero correlation attack?)
  78. how to implement non linearity criterea on s box to find non linearity of tha s plz explain .p

  79. Why can an arbitrary compression function mapping $\{0,1\}^{m+2^m} \rightarrow \{0,1\}^m$ not seriously be considered collision resistant?

  80. Jumblar: Using map locations as passwords

  81. Stuck on an affine cipher exercise
  82. Semantic security IND-CPA of Affine Hill Cipher
  83. Known Plaintext Attack A5/2

  84. Why should the factors $p,q$ of $n$ be half the bit length of $n$ in RSA?

  85. How is a "SHA256 reduced by X of Y rounds" built?

  86. Can you help me understand Pollard's rho example?
  87. What rule(s) for a good S-box is this one violating and how does it relate to non-linearity etc.?

  88. Quantative criteria to measure confusion and diffusion property of encryption algorithm
  89. How can I identify the linear equations for a block cipher with 4 different s-boxes?

  90. What are the relations between cryptanalysis of block ciphers such as AES and Kendall's tau coefficient?

  91. Why the permutation of the right hand rotor given in Rejewski's paper is $PNP^{-1}$?
  92. Break simplified DES
  93. XORing to detect decrypted value?

  94. Can/Which encryption algorithms be daisy chained to create a cryptographic computational puzzle?

  95. Why was the Navajo code not broken by the Japanese in WWII?
  96. Homogenous vs heterogeneous unbalanced Feistel networks?

  97. AES: a question about dual ciphers and security

  98. Kerckhoffs’ principles – Why should I make my cipher public?

  99. List of security protocols that have been proved to have bugs using formal methods
  100. how long does the cycle length have to be in stream ciphers?