# All Questions

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### What kind of encoding is used in these strings?

I think this is the BASE64 encoding but decoding by BASE64 returns meaningless chars. Help me to decode this. The value must be 3-digit numbers. Thanks in advance. AAABBXCXMQAAAAAFCZcxAAAAAAA= ...
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### Is it possible to find out whether a number is greater than another number without knowing the numbers?

Is it possible to construct a zero knowledge proof that one encrypted number is larger (or not) than another encrypted number without releasing the values of either numbers?
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### Generation of N bit prime numbers -> what is the actual range?

Short version: When generating a prime number of N bits, should I draw random numbers from the range $[0 , 2^n]$, or $[2^{(n-1)} , 2^n]$? Context: I'm trying to implement a toy-version of RSA as a ...
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### Why haven't military-precision channel GPS receivers been hacked yet (like game consoles or Apple devices)?

I wonder what is the encryption scheme in these high-precision encrypted GPS streams (the so-called "P(Y) code". If there's a master key needed, then it has to be in every device. How come the key ...
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### Forward pseudorandom permutation

Please consider the following scenario: The user A and B use their keys, K1 and K2 respectively. Each client have a vector of elements. Each client separately permutes his vector using his key and ...
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### Is it possible to hand-negotiate an SSL/TLS session?

I'm interested in trying to hand-negotiate an SSL/TLS session. Similar to how one would use telnet to port 80 and type GET / HTTP/1.1. I know there's a lot of steps ...
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### How to get PrivateKey from byte[] [on hold]

I have a PrivateKey in byte[] format. (Which is internally read from .key file) Now I am trying to get PrivateKey from the byte[] using "EC" algorithm My code snippet: ...
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### Using modulus in one time pad?

I would like to know what is the real purpose of using a modulus in the equivalent of a Vernam cipher: Data $d$, large number $M$ Assume the key length is λ bits. Then M could be 2^λ. k is picked ...
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### Perform general computation using a crypto algorithm as a building block

I have a somewhat special question. In our software we use a existing dongle which got cracked by our customers. The protection offered by the dongle isn't very sophisticated. For the moment I can't ...
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Is there any consensus (i.e. are there any research results) on the benefits and drawbacks of various padding schemes? Generally there seem to be two kinds of them: random paddings, like ISO10126 ...
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### Diffie-Hellman and man-in-the-middle attacks

See here for the man-in-the-middle attack on Diffie-Hellman that I'm concerned about: What is Diffie-Hellman? How do we combat this? I have two questions: Is one solution for both Alice and Bob ...
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### Is it possible (how difficult) to find MORE than one valid RSA signature?

Is it possible (how difficult) to find more than one valid RSA signatures for a given message m (after padded) and a public key ...
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### Which cipher type is the solved Zodiac Killer's 408 cryptogram? [on hold]

I downloaded CryptoCrack and I plugged in the ciphertext for the 408 cryptogram: ...
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### SHA-1 collision resistance

I'm researching on the SHA-1 algorithm and looking for reasons why it has fallen prey to differential cryptanalysis. I have read the research papers by Merc Stevens and Wang both of which describe how ...
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### Authenticating Very Short (Sub-Block) Data

If I'm encrypting very short/small data - like an int or a long (32 or 64 bits), does it make any sense to authenticate the ciphertext, when using an "online" mode of operation (like EAX)? ...
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### Is there any definition for “generic attack” in context of cryptography or more specific “hash functions”?

I'm searching a definition of "generic attack" in context of cryptography or more specific in context of "hash functions". I searched some books and the web but I did not found any definition for it ...
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### Is it feasible to use combination of ABE schemes for encrypting the data?

I have a peculiar requirement for preserving the shared log files. For example I have 1000 records which belong to different organizations as listed below and all the logs are present in a single CSV ...
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### how much will it cost me to encrpt apps and website? [on hold]

gentlemen,I have a question. am planning to make a website an two Apps for android and Iphone and I want to make its encryption very strong. I don't know how much it may cost me and how to do it. is ...
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### VKO GOST R 34.10-2001 (described in RFC4357), Key Agreement Algorithm. Looking for its implementation/detailed description/examples

VKO GOST R 34.10-2001 was described in RFC4357 Page 7 But the description is very poor. Here it is: This algorithm creates a key encryption key (KEK) using 64 bit UKM, the sender's private key, ...
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### Question about the security of Substitution-Permutation Network

In general, we execute key-mixing, substitution and permutation sequentially in a single round in a n-round SPN, but if we execute n-round key-mixing firstly, n-round substitution secondly and n-round ...
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### Finding algorithm: desire RSA's uniqueness and ECDSA's space efficiency

I am asking for help in finding a signature algorithm with the following property: Given a message m and a private key prikey, ...
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### Understanding Pseudo Random Generators

I've been taking a crypto course online. I have a good idea how PRG's and Stream Ciphers work, but I'd love to get some input to help visualize what is actually happening. I understand a seed is used, ...
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### Encryption with data loss protection

Is there an existing format out there that not only encrypts data but also protects against loss of data much like the QR codes can lose up to 33% of it's bits and the message is still recoverable. I ...
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### fuzzy commitment implemenation to make secure biometric template

I want implement some ideas from an article that is about making secure biometric templates using fuzzy commitment and fuzzy vault. I need to implement just the fuzzy commitment (fuzzy commitment is a ...