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Questions tagged [des]

Data Encryption Standard (DES) is a cryptographic block cipher algorithm.

Data Encryption Standard (DES) is a cryptographic block cipher algorithm.

DES encryption uses a 56 bit key. It is insecure and can be broken in a few hours. It should not be used for new projects.

DES on Wikipedia

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java.security.NoSuchAlgorithmException: Cannot find any provider supporting PBEWithMD5AndDES

I am getting the following Exception while executing my code. Here the code snippet which causes this error Cipher c = Cipher.getInstance("PBEWithMD5AndDES"); I have used javax-crypto.jar. Caused by: java.security.NoSuchAlgorithmException: Cannot…
Abhishek Singh
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Get 192bits cipher from 64bit blocksize in des

I was wondering, is it possible to extend the cipher byte length when block size 64bits (8byte) in DES? Its like this, When the input Blocksize is <=64bits the cypher size is 128bits for sure because of the PaddingMode.PKCS7 in DES. The below code…
Giliweed
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Size of key is too large for DES encryption

I was given string: exchanges key: exchanges1234 and need to encrypt it with 64-bit DES encryption. I try to use php to enrypt it. mcrypt_encrypt(MCRYPT_DES, $key, $str, MCRYPT_MODE_ECB) But it return PHP Warning: mcrypt_encrypt(): Size of key…
conandor
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Can we implement 512 key size with Triple Des algorithm

My question is can we extend key length of Triple DES to 512 instead of 168? How to prove that there is no 512 bits Triple DES and if I want to use very secure algorithm what is the maximum key length I can use in triple DES. How can I justify key…
tgh12
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AES Key From File Trouble

Program is running now. It runs but then crashes. In my files folder it creates an encrypted file but it is blank. It also does not produce a decrypted file at all. I also changed the bit size to 128. What else I am missing in order to properly…
user3294617
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Encryption and Decryption of File

I am trying to encrypt and decrypt a file. The file can be any file like txt, jpg, doc, pdf. The IV is prepended to the cipher text. but while decrypting if i read first 8 bytes it gives me different value then the value of IV while encryption. Here…
Ronak Patel
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DES encryption/decryption

I'm using a DES algorithm I found on the web. It works fine but I have a problem. As you know, DES encrypts/decrypts blocks of 64 bytes each. But what happens if in a big file the last block doesn't end at a 64 byte block boundary? I know, there…
gAeT
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PHP DES Encryption compatible with Delphi - encryption function

I am trying to create the encrypt PHP algorithm from this thread: how to sync encryption between delphi and php using dcpcrypt (see shunty's reply) Here is what I have so far: function encrypt($str, $key) { $keysize =…
KillerKode
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Cannot change the cipher key in Base64 Decoder

I have a pre-written code which is used to cipher the given plain text or vice-versa . The class has 3 methods, where in 2 methods can be used for encrypting and decrypting respectively. public class SqlCipherUtil { private Cipher ecipher; …
bali208
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C# DES ECB Encryption

I am having difficulty encrypting something in C#. I have 3 variables. First one is a 16 digit hex,lets call it X value I.E 0072701351979990 Second one is also a 16 digit hex value, lets call it Y I.E 3008168011FFFFFF These two values have to be XOR…
MariusvStraaten
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What should be the better way to implement DES encrypting and decrypting for a string?

I have gone through theory of DES and also AES, and it seems better way to use AES. But I didn't find any help on AES, that I can implement in my android application. So what should be better implementation of DES in my application. Can you share…
Pankaj Kumar
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How to decrypt a password des(unix) with 13 string with python

Here my decode a password with 13 string U5IhmemtXSSA. ===> admin G1Cbobnlhh9xA ===> flower What function or code should I use to decode a password like that?
gmps org
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Encrypt plaintext with DES algorithm

I'm trying to encrypt a plaintext using DES algorithm in PHP. I managed to code a working example in C#: String plaintext = "1y7wpc4iddseyrwez1lor8ow3297t.pd0bfl"; String pass = "rpsxi.t.rjsmklexarygfqyrrkhwdjh"; byte[] bytesPlain =…
Marcos Coleman
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Possible DES keys

I have two questions. How many DES-keys will produce the same first 32 bit ciphertext from the same plaintext? Example: Plaintext = 00 00 00 00 00 00 00 00 (hex) Ciphertext = 01 02 03 04 ?? ?? ?? ?? (hex) How many keys can produce this? If I get…
sverrets
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C - crypt() - Code takes longer to execute with 5 loops or more than with 4 loops but using the same parameter/hash

I'm taking an edx course called CS50. Maybe some of you are familiar with it. One of the problems set asks you to implement an algorithm to crack a password that was hashed using des-based encryption and is up to 4 characters. So far, so good. I've…
Cam Moreira
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