User A. Hersean

8 answers

219 votes

103k views

100 bookmarks

How much would it cost in U.S. dollars to brute-force a 256-bit key in a year?

brute-force-attack

Nov 8, 2011 at 10:51

6 answers

135 votes

96k views

96 bookmarks

Should we sign-then-encrypt, or encrypt-then-sign?

Nov 22, 2012 at 16:55

4 answers

113 votes

75k views

66 bookmarks

How should I calculate the entropy of a password?

passwords entropy

Aug 11, 2011 at 6:03

10 answers

86 votes

17k views

44 bookmarks

In end-to-end encryption, doesn't the server need to be trusted?

encryption public-key key-exchange

Dec 19, 2017 at 14:30

1 answer

60 votes

27k views

48 bookmarks

Easy explanation of "IND-" security notions?

provable-security chosen-plaintext-attack terminology chosen-ciphertext-attack semantic-security

Jul 3, 2015 at 11:03

2 answers

54 votes

12k views

28 bookmarks

Timing attack and good coding practices

timing-attack

Nov 21, 2016 at 6:52

3 answers

54 votes

24k views

32 bookmarks

Why Curve25519 for encryption but Ed25519 for signatures?

elliptic-curves ed25519 libsodium

Sep 1, 2015 at 22:16

4 answers

38 votes

7k views

6 bookmarks

After 20 years of AES, what are the retrospective changes that should have been made?

aes

Jan 18, 2021 at 13:47

2 answers

35 votes

27k views

7 bookmarks

Is AES-256 a post-quantum secure cipher or not?

aes post-quantum-cryptography brute-force-attack

Mar 16, 2013 at 15:28

2 answers

34 votes

5k views

28 bookmarks

What are recommended, general strategies to start block-cipher design and/or analysis?

cryptanalysis block-cipher algorithm-design

Sep 5, 2016 at 19:49

1 answer

34 votes

14k views

7 bookmarks

ECDSA, EdDSA and ed25519 relationship / compatibility

elliptic-curves dsa ed25519 eddsa

Apr 15, 2018 at 22:00

2 answers

30 votes

6k views

14 bookmarks

AES-GCM Disadvantage

authenticated-encryption gcm

Jul 31, 2014 at 19:25

4 answers

28 votes

5k views

8 bookmarks

Why is FIPS 140-2 compliance controversial?

fips-140

Nov 21 at 20:11

1 answer

26 votes

6k views

18 bookmarks

Is a hash a zero-knowledge proof?

zero-knowledge-proofs

May 28, 2019 at 18:58

2 answers

24 votes

8k views

8 bookmarks

Elliptic curve ed25519 vs ed448 - Differences

ed25519 ed448

Feb 20, 2019 at 10:00

1 answer

24 votes

16k views

12 bookmarks

What are the odds of collisions for a hash function with 256-bit output?

hash collision-resistance

Aug 27, 2016 at 16:54

2 answers

18 votes

2k views

2 bookmarks

Why was the winner of the AES competition not a Feistel cipher?

aes substitution-cipher feistel-network

Sep 29, 2013 at 17:23

3 answers

18 votes

3k views

4 bookmarks

UMAC: to what extent is it in use today?

mac

Jul 25, 2011 at 20:43

2 answers

13 votes

9k views

8 bookmarks

How safe are Libsodium Crypto Boxes?

libsodium

Nov 7, 2017 at 9:41

3 answers

13 votes

2k views

9 bookmarks

How are points on an elliptic curve discretized?

elliptic-curves

Aug 10, 2020 at 4:56

1 answer

13 votes

4k views

5 bookmarks

Security considerations on "expand 32-byte k"-magic number in the Salsa20 family of stream ciphers?

encryption stream-cipher salsa20 constants

Oct 21, 2013 at 10:51

1 answer

11 votes

4k views

8 bookmarks

Relation between entropy and min-entropy

entropy

Nov 8, 2018 at 11:14

7 answers

10 votes

2k views

4 bookmarks

In search of a pedagogically simple example of asymmetric encryption routine?

public-key algorithm-design pedagogy

Sep 27, 2019 at 15:28

2 answers

10 votes

413 views

3 bookmarks

What role plays Quantum Fourier Transformation in Shor's integer factorization algorithm?

factoring quantum-cryptography

Oct 15, 2013 at 21:21

1 answer

10 votes

4k views

6 bookmarks

Curve25519 over Ed25519 for key exchange? Why?

elliptic-curves key-exchange dsa ed25519

Mar 19, 2019 at 10:25

1 answer

10 votes

6k views

6 bookmarks

Description of signatures with message recovery (as in ISO/IEC 9796-2 and EMV Signatures)

hash signature reference-request message-recovery

Jun 20, 2014 at 13:46

2 answers

9 votes

821 views

2 bookmarks

What do NM-CPA and NM-CCA mean?

authenticated-encryption terminology chosen-plaintext-attack chosen-ciphertext-attack malleability

Mar 15, 2019 at 17:05

2 answers

7 votes

560 views

3 bookmarks

Why ECDSA has its form?

public-key elliptic-curves signature dsa

Dec 13, 2018 at 3:44

1 answer

6 votes

928 views

2 bookmarks

Is forward secrecy overhyped or necessary?

key-generation forward-secrecy

Feb 8, 2019 at 19:32

9 answers

6 votes

817 views

8 bookmarks

Soft question: What are examples of beautiful proofs in cryptography?

history

Jun 4, 2019 at 15:17

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