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Questions tagged [des]

Data Encryption Standard (DES) is a symmetrical encryption algorithm.

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Strength Blowfish and DES with current quantic computing and mandating backdoors

What is the strength of algorithms such as DES (Rijndael) and Blowfish used in password manager Safe password, with the current development (2018) of quantum computing, the former parallel processing, ...
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What would be a better encryption algorithm then RSA_DES_EDE3_CBC?

First off, please let me explain why I'm asking this at all: The default implementation of EnvelopedCms is using AlgorithmIdentifier which by itself will use RSA_DES_EDE3_CBC or OID 1.2.840.113549.3....
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2answers
1k views

In cyptography what is “Key Space”?

What is a Key space and how does it relate to the strength of a cryptosystem? Comment on the strength of the DES algorithm with a 56 bit key. What relevance does the key space have for passwords? ...
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1k views

Decrypting Des encryption

I am interested in learning different encryption techniques and i am trying to understand one implementation in-particular. I have set the password in the application and now want to understand how ...
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3answers
15k views

Is the 3DES algorithm secure?

Can we use the 3DES algorithm for exchanging confidential information? I am using it in my project. Security code reviewer has raised a bug saying that it is not secure but I see that it is mentioned ...
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1answer
157 views

3DES Security - safe use cases

What are safe use cases for 3DES? Is it safe to use it in situations where you are encrypting smaller amounts of data? After the recently published 'birthday attacks' on 3DES (eg SWEET32), I've read ...
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1answer
201 views

Which protocols are the most secure to achieve authentication and encryption for a client downloading data from a sever?

I'm new to Information Security so please bear with me if this question is quite trivial. I want to design a secure protocol that allows someone to download a piece of data that belongs to them from ...
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1answer
1k views

what does key size (64 bit) in DES means

I im taking cryptography classes and learned that the key size of DES is 64 bits. So if the key is array of Alphabetic char, and 1 char takes 8 bits then 64/8 = 8 . So the key can be only 8 char ...
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1answer
404 views

The reason of using XOR operation in cryptographic algorithms

I notice that some cryptographic algorithms involve using XOR operation with the key (Even AES uses XOR to derive the round keys). My question is why specifically XOR? How about OR or NAND or some ...
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1answer
614 views

3DES is used as symmetric or asymmetric encryption?

checked couple of online options which says 3DES is symmetric encryption(which means a single key is shared between two to encryption and decryption) but I have seen many EDI production system(AS2 ...
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1answer
3k views

The use of DES-CBC3 for TLS

When researching some TLS compliant software I found some mentions of DES-CBC3. Further research shows that it is probably simply a name of OpenSSL for 3DES-EDE-CBC (under section "CIPHER SUITE NAMES" ...
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1answer
3k views

Why is CBC-MAC insecure for variable length input?

Can anyone explain why CBC-MAC is not secure for variable length message? I read many books, but there are still some confusion. Like the highlighted parts in following pictures Slide 32: Slide 33: ...
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1answer
269 views

DES Decryption followed by Encryption, will it produce the original text?

This is regarding DES. My question is, if a plain text is first decrypted (with the decryption algorithm) using Key K1 and then encrypted using same K1, would the result still be the original plain ...
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3k views

Why was DES with 112 bit keys (IBM) reduced to 56?

On the French wikipedia page about DES it says that the original DES algorithm from IBM used 112 bit keys. Why did they reduce this to 56 bits? Edit: ok NSA convinced IBM but today it seems like a ...
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2answers
5k views

How does the meet in the middle attack work on double DES?

I am having trouble understanding the meet in the middle attack and how it works on double DES. I understand that on single DES the key length is 2^56 but why when using double DES is it 2^57? Can ...
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1answer
2k views

Why does my SHA256 certificate get encrypted with 168 bit 3DES?

We use S/Mime certificates for internal emails within our company. The certificates signature algorithm are all SHA256RSA with a hash of SHA256. I have confirmed the public keys are RSA(2048bits). ...
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0answers
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Key Hierarchy and key Encryption

If i have two 56-bit DES keys, and I use these two key to encrypt a 256-bit AES key. Like this: K_AT encrypts K_BT and K_BT encrypts K What is the effective security of key K? Is it 2 X 56 Bits?
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1answer
281 views

32-bit Radio Voice Encryption, is it really that secure? If so, how?

I'm a student studying Electrical and Computer Engineering and a ham radio operator (i.e. my knowledge of encryption is basic). More and more, police and local government radio has become encrypted, ...
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1answer
480 views

cracking krb5 passwords (des3-hmac-sha1 and des-cbc-crc ) [closed]

I'm trying to audit kerberos passwords. The available formats are des3-hmac-sha1 and des-cbc-crc but I cannot find a possibility/a tool to crack them. For other hash-types I used John the Ripper, but ...
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2answers
29k views

TLS_RSA_WITH_3DES_EDE_CBC_SHA reported as 112 bits

I am no expert in this area but after some searching I am not too sure about the solution. An external vendor doing a pentration test on our server reported that we have ...
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2answers
8k views

Why has the NSA had a hand in deciding on encryption standards?

The NSA has had a large hand in the design of at least two significant encryption standards: the Digital Encryption Standard, and its successor, the Advanced Encryption Standard. Because of their ...
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1answer
859 views

How to calculate cryptographic checksum using 3DES-outer-CBC mode

I want to calculate a cryptographic checksum using 3DES in outer CBC mode. As I know (and tried Googling also ) 3DES is an encryption algorithm, I'm not getting getting any information about how it ...
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1answer
2k views

How to look up permutation tables in DES?

For finding out the final permutation or initial permutation in DES Encryption, we need to look up permutation tables. Taking an example: Find the output of the initial permutation box when the input ...
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1answer
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What is the output length of CBC with zero input?

Given this formula for CBC encryption from 6.2 The Cipher Block Chaining Mode what is the output length of CBC if plaintext P is of length 0?
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1answer
8k views

Understanding Key Serial Numbers (KSN) in Derived Unique Key Per Transaction (DUKPT)

I have a number of questions regarding Key Serial Numbers (KSNs) in DUKPT: KSNs are 8 - 10 bytes long. Older implementation are 8 bytes whereas newer ones are 10 bytes. Do I risk being incompatible ...
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2answers
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Why is there a “des-ede3-cbc” in my rsa private key?

I have created an OpenSSL RSA private key and certificate request with 4096 bit with the following command: openssl req -newkey 4096 When I view the private key with openssl asn1parse -in privkey ...
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1answer
743 views

Getting multiple key matches on plaintext/ciphertext pairs in double DES

I'm trying to implement a Meet-in-the-Middle attack and just to test it out I've done some hardcoding of values, which is simply this block of simple code: byte[] key1 = new byte[] { 0x20, 0x00, 0x00,...
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1answer
432 views

DES-CBC: Two ciphertext blocks c2 and c5 are equal. Why would this leak information?

Here, suppose that we were able to observe the ciphertext that we know had been encrypted in CBC mode, then how knowing of c2 and c5 ciphertext blocks would leak information ? My professor asked us ...
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1answer
4k views

Real time application of AES and DES [closed]

I am writing a paper on reducing the power consumption of security protocols. I am having trouble identifying sources that describe real-time usage of DES and AES, and how often they are used. I plan ...
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2answers
2k views

Find DES encryption key having input and encrypted output

Having the source string: S3nh4#1 And the generated encrypted string: csf7259aT07Rw Using this script, it identified the algorithm used to encrypt as DES(Unix) I wonder if it is possible (in ...
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1answer
1k views

Mapping of plaintext and ciphertext in DES

The plain text and the cipher text have a one to one mapping. Given a pair of those, can there be multiple keys used to generate the same pair? Or can a particular plain text - cipher text mapping be ...
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2answers
292 views

Do DES keys have to be random?

In stream cipher (namely the OTP ) . The pad which the plain text is Xored with has to be random to achieve perfect secrecy , or psudorandom to ensure semantic security Dose this apply to DES or ...
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2answers
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What is the difference between double DES and 3-DES?

I'm not getting the exact main point of 2-DES and 3-DES. I would like to know the difference between the two; why 3-DES is chosen over 2-DES?
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1answer
596 views

How do I identify a DES encryption key in a dump file using winhex?

I've created a C# program that encrypts and decrypts a file. The encryption method is DES. The program is exactly the same as in the following link, except that the part that removes the key from ...
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1answer
1k views

Cracking DES(Unix)/MD5 ARP

This is a basic example of an Unix Pass Encryption. I have a little Hash of MD5 ARP: user50:$apr1$w7YNTrjQ$0/71H7ze5o9/jCnKLt0mj0 user60:$apr1$AIw2h09/$Ti0TRlU9mDpCGm5zg.ZDP. I need to find the ...
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2answers
14k views

How do I decrypt an Adobe Triple DES ECB-mode encrypted password?

So as you may have heard, the Adobe user database with 130 million records was leaked recently. I want to find out what password I used for the Adobe account I created to make sure that I'm not using ...
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1answer
6k views

How does DES provide confusion and diffusion? [closed]

I know that Data Encryption Standard (DES) provide strong security but I want to know how does it provides confusion and diffusion?
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Why two key DES algorithm provides only 80 bits security

In the wiki link, it is mentioned that due to "chosen-plaintext" or "known-cipher" attacks, two key DES provides only 80 bits of security. My question is how these attacks work and how did NSIT came ...
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2answers
168 views

How is the key obtained when I login via VPN?

So, I configure my VPN (let say which uses PPTP protocol), enter the server name, username and password. Then, I visit a website. Before that, my request is encrypted using AES with some key. That ...
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2answers
352 views

Why is SHA-3 (keccak) considered more secure than DES when you can attempt to crack it 3x faster? [closed]

Hash.Type....: descrypt, DES(Unix), Traditional DES Speed.GPU.#1.: 6215.8k/s Hash.Type....: SHA-3(Keccak) Speed.GPU.#1.: 20514.1k/s see: http://hashcat.net/forum/archive/index.php?thread-2085.html ...
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2answers
2k views

Is my SIM card vulnerable to DES cracking?

Srlabs have recently published article stating that many SIM cards can be exploited using vulnerability in DES: [...] While the option exists to use state-of-the-art AES or the somewhat outdated ...
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2answers
118k views

Security comparsion of 3DES and AES

Which one is more secure and least possible to be broken through cryptanalysis AES or 3DES (no matter performance)? I need to use encryption for my projects to store and secure sensitive information ...
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1answer
2k views

Is the DES “mangler” function invertible?

The DES symmetric cipher is based on a Feistel network operating repeated on 32-bit halves of the 64-bit block. The usage of Feistel means that the "mangler" function used does not need to be ...