# All Questions

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### Can substrings of a long string be efficiently authenticated?

Suppose one has a (strong) shared secret key and wishes to authenticate a very long string in a way that will allow the verifier to verify small substrings without reading much of the stored data and ...
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### differential and linear cryptanalysis

I have been reading about differential and linear cryptanalysis. They were mainly introduced by Adi Shamir and Biham to show weakness of DES. However, many of articles state that they have been ...
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### KeeLoq showing that decryption is indeed the inverse of encryption

In some text I am reading, there is an exercise asking to show that KeeLoq decryption function is the inverse of the encryption function. Details about KeeLoq are given in the Wikipedia article. As I ...
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### What is the private key in RSA?

I'm new to cryptography and I have a doubt: I read some pages a bit different definition for the RSA private key: In 1 - (n, d) In 2 - ...
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### Do you need a HMAC if decryption attempts are severely limited?

I am considering an application where data bandwidth is extremely limited, and considering removing message authentication codes from encrypted transmissions. The encryption method is currently ...
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### Is there any function that does not suffers birthday problem?

I am eager to know that if there is any function that does not suffer birthday problem and how to prove it formally that the function is not suffering the birthday problem.