User alpominth

4 votes

3 answers

920 views

If I encrypt a plaintext with different keys for each block, will I have the same security as a one-time pad?

asked Jul 2 at 22:44

3 votes

3 answers

1k views

If I hash different seeds with same size of hash output and XOR on plaintext, is it secure as One-time pad?

asked Jul 3 at 1:08

3 votes

1 answer

256 views

What is the post-quantum security of encryptions schemes based on transpositions?

asked Apr 19 at 5:19

2 votes

1 answer

560 views

Is there a simple formula to calculate how many inputs generate same outputs in cryptographic hash functions, being the input larger than the input?

asked Apr 3 at 6:39

2 votes

1 answer

80 views

When the input size in a PRF is larger than the output and many inputs will generate the same output, but why AES-256 in CTR mode is considered safe?

asked Mar 3 at 3:25

1 vote

0 answers

127 views

Why do the hash functions tested by SMhasher appear to be exceptionally fast?

asked Mar 10 at 20:34

1 vote

0 answers

64 views

How to estimate the collision resistance of a hash function if a secondary key is used (keyed hash function)?

asked Mar 17 at 23:15

1 vote

1 answer

162 views

Does an increase of message size increase the number of guesses to find a collision?

asked Mar 17 at 23:57

1 vote

1 answer

43 views

Is it safe or reasonable to use the key parameter in a cryptographic hash function as a counter?

asked Mar 18 at 2:21

1 vote

1 answer

78 views

In CTR block cipher mode of operation, can I reuse the nonce with another key for encrypting another plaintext if using different counters?

asked Mar 20 at 5:30

1 vote

2 answers

283 views

How changing a single byte/word in a substitution box affects the inverse result?

asked Apr 12 at 6:34

1 vote

2 answers

731 views

Are the null bytes produced by a True Random Number Generator a security issue when using it as a source of entropy for keys in One-time pad?

asked Jul 25 at 23:03

1 vote

1 answer

129 views

Why hashing a seed to generate a key and using chaining to get the rest of key matterial is not secure?

asked Mar 2 at 19:37

1 vote

1 answer

49 views

Is KangarooTwelve hash function suitable for generating very large key material as Shake-256 is?

asked Dec 2 at 0:14

0 votes

0 answers

35 views

What is the security of XTS block cipher mode of operation if the key is much larger than the block size?

asked Nov 13 at 0:11

0 votes

1 answer

57 views

May I use the same One-time pad key two times if I encrypt it with a block cipher using two different block cipher keys?

asked Jul 23 at 0:02

0 votes

1 answer

69 views

If encrypting with a hash function in counter mode, will the security of this scheme be at most minimal{input,output}?

asked Jun 18 at 1:00

0 votes

0 answers

60 views

Hashing a seed full of entropy with a cryptographic hash function and emiting a key with the same size as input: can a collision attack occurs?

asked Mar 22 at 8:30

0 votes

1 answer

133 views

If I encrypt two plaintexts with different keys, XOR the ciphertexts and send to an adversary, what can he/she do with what I sent?

asked Mar 26 at 4:13

0 votes

0 answers

22 views

Once a secure hash function built up a (fast) internal hash table, can data to be hashed be different from the data inserted when doing the lookups?

asked Mar 12 at 21:51

0 votes

1 answer

68 views

Is there a way to make a pseudorandom function to generate decimal numbers in a specified range and not only producing big ones?

asked Mar 12 at 23:49

Stack Exchange Network

21 Questions

If I encrypt a plaintext with different keys for each block, will I have the same security as a one-time pad?

If I hash different seeds with same size of hash output and XOR on plaintext, is it secure as One-time pad?

What is the post-quantum security of encryptions schemes based on transpositions?

Is there a simple formula to calculate how many inputs generate same outputs in cryptographic hash functions, being the input larger than the input?

When the input size in a PRF is larger than the output and many inputs will generate the same output, but why AES-256 in CTR mode is considered safe?

Why do the hash functions tested by SMhasher appear to be exceptionally fast?

How to estimate the collision resistance of a hash function if a secondary key is used (keyed hash function)?

Does an increase of message size increase the number of guesses to find a collision?

Is it safe or reasonable to use the key parameter in a cryptographic hash function as a counter?

In CTR block cipher mode of operation, can I reuse the nonce with another key for encrypting another plaintext if using different counters?

How changing a single byte/word in a substitution box affects the inverse result?

Are the null bytes produced by a True Random Number Generator a security issue when using it as a source of entropy for keys in One-time pad?

Why hashing a seed to generate a key and using chaining to get the rest of key matterial is not secure?

Is KangarooTwelve hash function suitable for generating very large key material as Shake-256 is?

What is the security of XTS block cipher mode of operation if the key is much larger than the block size?

May I use the same One-time pad key two times if I encrypt it with a block cipher using two different block cipher keys?

If encrypting with a hash function in counter mode, will the security of this scheme be at most minimal{input,output}?

Hashing a seed full of entropy with a cryptographic hash function and emiting a key with the same size as input: can a collision attack occurs?

If I encrypt two plaintexts with different keys, XOR the ciphertexts and send to an adversary, what can he/she do with what I sent?

Once a secure hash function built up a (fast) internal hash table, can data to be hashed be different from the data inserted when doing the lookups?

Is there a way to make a pseudorandom function to generate decimal numbers in a specified range and not only producing big ones?