Linked Questions

-1 votes
3 answers
931 views

Why wouldn't everyone encrypt with a One Time Pad? [duplicate]

A One Time Pad (OTP) sounds perfectly secure if we are to believe Wikipedia. But on the surface it also sounds ridiculously impractical - how does one securely distribute the OTP? Idea: why not have ...
omatai's user avatar
  • 131
3 votes
4 answers
2k views

Is the Vernam (One Time Pad) cipher useful? [duplicate]

By profession I’m a programmer. I don’t know a lot about how cryptographic algorithms are implemented, or even where I’d start, and I don’t know about cryptanalysis, but as I work in Blockchain ...
Matthew Layton's user avatar
4 votes
2 answers
1k views

Does a Vigenère cipher with SHA-512 and a little foresight turn into a one-time pad? How safe can it be?

I'm doing some exercises. Of course, I have read about the weaknesses of the Vigenère cipher because it repeats the key. But what if I use a different hash every time? The hash of the "key + an ...
nicanz's user avatar
  • 141
2 votes
2 answers
1k views

Can I generate OTP secrets by using a hash?

Since I learned about one time pads in last security lecture, I'm quite fascinated how easy the concept is, but how it still is absolutely safe. Learning from implementing a multi time pad attack, ...
Bernd Strehl's user avatar
4 votes
3 answers
897 views

One Time Pads and reuse of the decrypted message?

How is it insecure when Alice encrypts a message with a One-Time-Pad to Bob, and Bob then uses the decrypted message from Alice as the next One-Time-Pad? For example: Alice sends Bob a message ...
cryptodragon's user avatar
3 votes
1 answer
3k views

How vulnerable is one-time pad (OTP) encryption, if the OTP is used twice, with a random substitution scheme

After reading up on the one-time pad (OTP) encryption method, I could see how it would offer unbreakable encryption if used properly. Moreover, I looked at how the OTP could be broken if the OTP-key ...
Horst's user avatar
  • 143
-5 votes
4 answers
981 views

Multiple Encryption - One-Time Pad

It is known that One-Time Pad(OTP)s are theoretically unbreakable but impractical for use because of the size of the key length. But what if multiple encryption is used? Not to encrypt the first ...
Fathima Abdur Rahman's user avatar
2 votes
2 answers
485 views

Can one construct OTPs without using XOR?

The typical version of the one-time-pad (OTP) uses XOR to combine a key pad and a message. ($c=m\oplus k$) Now let's assume some other scenarios which have the practical application of blinding. Do ...
SEJPM's user avatar
  • 46.1k
1 vote
4 answers
362 views

Including the next random One Time Pad as part of the encoded message?

I've tried to do something very simple here, which is to encrypt a message with a one-time-pad (OTP) and include the next OTP as part of that same encrypted message. i.e. The first message consists of ...
Sci's user avatar
  • 21
1 vote
2 answers
523 views

One time pad- XORing or substitution

I have come across 2 versions of otp while reading it and want to confirm it. they have taken a plain text consisting of alphabets where they are shifted and replaced by alphabets itself. XORing of ...
CuriousCurie's user avatar
5 votes
2 answers
379 views

Perfect Deniability of a MAC

Overview One feature that is often underlooked of the One-Time Pad is its perfect deniability. i.e. If Alice sends a message to Bob that is seen by Eve then if Eve later goes to Alice with the ...
edggy's user avatar
  • 453
0 votes
1 answer
321 views

XORing to detect decrypted value?

So I am doing a CTF and I have found a text that is full with hexadecimal encrypted value with XOR (that was a given hint from the previous flag). I don't have the key but I know the length of the key ...
Jack's user avatar
  • 19
1 vote
1 answer
164 views

Perfect Deniability of a MAC Protocol

I proposed an idea of Perfect Deniability of a MAC I tried to come up with a protocol that satisfies those security requirements as well as the normal security requirements of a MAC One-Time MAC ...
edggy's user avatar
  • 453
1 vote
0 answers
54 views

Truly Random Values [duplicate]

I am trying to build a one-time pad encryption software and I am thinking about simply using /dev/random to generate keys. My question is: Is it ...
Jishan's user avatar
  • 111