8k views

### Many time pad attack (XOR) [duplicate]

The question is quite similar to Many time pad attack and I was trying to rely on the top answer, but still am a bit confused, so any explanation and help will be much appreciated. Assume I have a ...
4k views

### decryption many time pad [duplicate]

I have eleven ciphertexts that were encrypted with the same key (which I don't know). I want to decrypt the last ciphertext. I read similar question like Many time pad attack but I can't solve my ...
2k views

### Stream Cipher : Never use stream cipher key more than once [duplicate]

Possible Duplicate: Taking advantage of one-time pad key reuse? How does one attack a two-time pad (i.e. one time pad with key reuse)? Denote C is cipher text, m is message, and PRG(k) is a ...
876 views

### Two-timing a one-time pad [duplicate]

Is a one-time pad still breakable on a depth of 2+ if the plaintext is completely random? I'm assuming this idea is wrong, mostly because it occurred to me, but let me walk you through my logic so ...
1k views

### Solving for a One-time pad cipher help ; crib dragging doesnt work (no surprise) [duplicate]

Basically we're given the text 7ECC555AB95BF6EC605E5F22B772D2B34FF4636340D32FABC29B 73CB4855BE44F6EC60594C2BB47997B60EEE303049CD3CABC29B 64C6401BAF45F6A930435F3DF875C4E102F8742A45C824AFCA9B ...
511 views

### many time pad attack [duplicate]

I am a beginner in cryptography. I studied many time pad attack and now I want to solve a popular exercise, It consists 11 ciphertexts (s1,s2,...,s11), that encrypted by a same key and I want to find ...
542 views

### What is the significance of the Period of a Steam Cipher [duplicate]

If we only know the period of a Stream Cipher, let's say 150-200 bit in length, how can we use this information to attack a stream cipher? Taking a look at this link, What is the period of a cipher? ...
590 views

### How can I find two strings $m_1$ and $m_2$, knowing that I know $m_1 \oplus m_2$? [duplicate]

Possible Duplicate: How does one attack a two-time pad (i.e. one time pad with key reuse)? I recently started to follow the cryptography class of Dan Boneh on coursera.org and the first part is ...
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### XOR and key reuse [duplicate]

I've been doing a bit of reading on the use of XOR and the dangers of key reuse. I'm aware that reusing a key can open a door for a frequency analysis attack on my plain text. So far, everything ...
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Why is it that a one time pad is vulnerable is the key is shorter than the message? I know that if a key is reused across multiple plaintexts, you can XOR two existing ciphertexts to get the pad, but ...
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### Decrypt Messages With Reused Pad [duplicate]

I have 2 messages which have been encrypted using the same pad. I know that if i xor these 2 messages together the key falls out. I am confused in how to figure out what the 2 messages are from the ...
60 views

### What to do with this specific scenario of a key reuse [duplicate]

I am brand new to the world of cryptogrophy. I am trying to decrypt a many-time-pad. I understand the methodology of using the XOR to get the messages. C1 XOR C2 = M1 XOR M2 Now my question lies in ...
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### Computing A, B given A+K and B+K [duplicate]

In his writeup of the Solitaire keystream generator algorithm, Bruce Schneier warns not to use the same key for two different messages: The first rule of an output-feedback mode stream cipher, any ...