Questions tagged [encoding]

Encoding is the act of transforming information from one form to another. In cryptography, encoding is typically used to refer to an unkeyed process that does not provide any security in itself, but just changes the representation of information into a more convenient form.

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Is “6 bit packed ASCII” an effective encoding to obscure text data?

I wrote a routine for a former employer that took the low six bits of ASCII text and "compressed" by cramming the bits together, so that 4 bytes reduced to 3. This had the advantage of automatically ...
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Is this an effective obfuscation technique?

Long ago I created a simple program which obfuscated a file by taking the first byte, then XORing it with the second, taking the (original) 2nd byte and X-ORing with the 3rd, etc, down the line. The ...
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What do the last chunks of the output string of Scrypt contain?

When you use scrypt to hash a string, it will generate something like: ...
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Do RSA keys contain a checksum mechanism? [duplicate]

I'm new to cryptography, and I was making an experiment a few minutes ago, but I want to have some deeper knowledge about RSA public and private keys. I have a set of keys One begins with ...
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Encryption-then-encode or encode-then-encryption?

I have this question in which I m struggling. I have read in many sites about encrypt-then-mac etc. If the confidentiality for transmission is needed, discuss the feature for the order of encryption ...
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662 views

Numeric base conversion in cryptosystems?

I have been wondering if numeric base conversion has ever found an application in cryptography. By base conversion, an example that is probably familiar is Base64 encoding. This is an example of ...
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Do I need to worry about timing attacks in Base64 encoding/decoding of private keys?

Do I need to worry about timing attacks in Base64 encoding/decoding of private keys? This is a common operation (ex. PEM keys) and is variable time in typical implementations.
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Huffman coding is a prefix code, proof [closed]

How would you prove that Huffman coding $C$ is a prefix code, i.e $$\forall x,y \in C,\ \forall z \in \lbrace 0,1\rbrace^*,\ x\not=y||z$$ Using induction according to the number of items to code? ...
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How to calculate secret key size of a CP-ABE scheme

How can I calculate the real size of key in a CP-ABE scheme. For example, I have this GSWV scheme: Fuchun Guo, Willy Susilo, Duncan Wong, Vijay Varadharajan: CP-ABE with constant-size keys for ...
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How to encode a message to MD5?

I have faced a problem to understand MD5 algorithm.My question is weather the original input message is converted to binary value in MD5 before using the input message as parameter in four Feistel ...
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Algorithms for Cyrillic encryption

I am working on a cryptography application which is to be used in my country. I tried looking up to see if there are any algorithms that support the Cyrillic alphabet, but I found none. Do you know of ...
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Decoding base64 encoded message with a key

I am pentesting a database that where I found data which was base64 encoded. I tried the usual method of decoding base64, which didn't work. Later, I found in ...
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Would it be better to split a file and then encrypt, or vice versa?

Assuming that you are paranoid before storing your file (distributed across a shared location), which will be the best case scenario: splitting the file first and then encrypting or encrypting first ...
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Is there an existing cryptography algorithm / method that both encrypts AND compresses text?

So I'm trying to find a method of encryption that not only obfuscates text, but also compresses the result. For example, if I encrypted ninechars, the ideal result ...
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Weird base64-like (?) encoding [closed]

I have some encoded strings which are probably encoded in a base64-variant - except that there aren't only 64 chars, but all the (printable) ASCII chars between 33 and 126 (0x21 to 0x7E). I've ...
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Is there specific name for simple XOR with ADD/SUB encoding?

Several years ago a group of malware authors began using code like this: for (j = 0; j < length; j++) ptr[j] = (ptr[j] ^ VALUEA) - VALUEB; for encoding, and ...
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How to determine the RSA Private key size from the Public.key file?

Question: How to determine the RSA Private key size from the Public.key file? Just roughly, how big it could be? ...
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1answer
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What are coding schemes for timing channels

I know we can hide information in the inter-packet delays, e.g. we can generate a code-book that each code-word corresponds to a message and is generated by realization of a specific random process. ...
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Is there a practical security difference between OTP with letters and OTP with numbers?

Is there a practical security difference between “OTP with letters” and “OTP with numbers”? If, for example, I encrypt a letter message using Tabula Recta with a random letter key, I would get: <...
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Are specially designed fonts sometimes used in cryptography?

As a font designer, I was thinking that it would be very easy to design a special font that could either jumble characters of a language (or of a code) or simply (with the features offered by the OTF ...
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1answer
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Huffman encoding of hashes

I have a huge list of MD5 hashes, which takes up quite some space. I wonder whether I would achieve (some) compression by encoding the characters (which are A-F 0-9), with Huffman coding. I made a ...
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1answer
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Encoding a message to a point of curve y^2=x^3+7 and Bitcoin Core

Where should I look at in Bitcoin Core source code to figure out how the signature process transform a message in a curve point? To sign a transaction (message) in the Bitcoin system, you need to ...
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How to securely map an element from an smaller domain to the other element in a large domain

Problem: I have a small sized domain, say s-bit. It's clear that the probability for an adversary to guess an element is $ \frac{1}{2^s}$. I need to make the probability negligible. However, I need to ...
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Koblitz encoding a message to a point, what is the “associated auxiliary base parameter”?

I am looking at the Koblitz method for encoding a message as an elliptic curve point. The first step given in the paper I'm reading is: "Choose an elliptic curve and its associated auxiliary base ...
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Solving Quadratic equations in Galois Field (2^163)

Hello I am working on implementing a message to elliptic curve point mapping hardware circuit I have done some research and found out the koblitz mapping method: I will be using a field of binary ...
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Reversing a Psuedo Crytographic Hash [closed]

I'm trying to get a better understanding of cryptographic hashing. Take the example transformation function below, is it possible to reverse this formula to solve/isolate for message[i]? ...
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How to perform frequency analysis of a substitution cipher using a Base64 alphabet

Let's imagine a cipher that works like the following: Plaintext is encoded to Base64. The characters in the encoded plaintext are substituted with a randomly shuffled character set(A-z, 0-9, -, _, =)....
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Infer encoding mechanism from $n$-grams distance?

I have a series of obfuscated strings which across the set of strings have regions of high variance and regions of low variance – implying some encoding mechanism as opposed to an encryption procedure ...
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Can I remove newlines in a public key?

Can I remove new lines from the RSA public key file to get a one line string? So the question is if the key looks like this AAA BBB CCC or ...
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1answer
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Base64 for a hash algorithm [closed]

May be a silly question, but I am really curious. If a hash algorithm uses Base64 in the process of hashing a string for example, it is still considered a hash algorithm, even though it uses an ...
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How to find modulus from a RSA public key?

I am studying the RSA cryptosystem. The public key consists of $(n, e)$, the modulus (product of two large primes), and the encryption exponent. I want to separate the modulus $n$ and exponent $e$. A ...
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How do I test my encryption? (absolute amateur)

I am a hobby programmer with a background in biology and have developed an encryption program based on DNA. I tried to make it hard to crack, but it's essentially a substitution cipher and uses the ...
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How secure is this use of Ziv-Lempel encoding?

I'm reading patent application US 20120278897 A1 — “System and method of sort-order preserving tokenization”. Near the bottom they describe their token generation algorithm, which basically involves ...