Questions tagged [ciphers]

In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. To encipher or encode is to convert information into cipher or code.

Filter by
Sorted by
Tagged with
0
votes
0answers
3 views

Chosen Ciphertext Attack textbook RSA [migrated]

I'm trying to perform a chosen ciphertext attack against an RSA oracle. I have c as the ciphertext I want to decrypt, e and n. I already know that I could choose a number r, compute r^e * c, make the ...
1
vote
0answers
48 views

What is the relation between cipher suite and certificate? [duplicate]

I generated my self signed certificate using openssl and I chose ECC keys (prime 256v1) for root certificate but while authenticating with the server i.e. IBM cloud and my device the negotiated cipher ...
20
votes
4answers
2k views

Do you rather trust a widely adopted algorithm or an underdog if they're cryptoanalytically on a level playingfield?

If it comes to the security a hashing or encryption algorithm provides, we never know the full story. There's that part that we (respectively the public research) understand and can reason about, but ...
2
votes
0answers
37 views

Best resource to verify weak cipher suites [closed]

Many tools enable to list accepted ciphers but not all of them verify if these ciphers are secure. For example, Nmap with script ssl-enum-ciphers ranks some ciphers as secure even though actually this ...
0
votes
1answer
78 views

dm-crypt 2.0.3 + luks: salt auto-generated? what affects decryption speed?

I am trying to encrypt one of my primary Linux partition (5GB) by following this example to encrypt. I want to confirm some of my understandings: Salt is automatically generated by cyrptsetup with ...
0
votes
1answer
53 views

Site use weak cipher and TLS older version

I just tested a site and it looks like the certificate uses weak ciphers but the certificate is new. Can this issue be related to the Certification Authority that provides the certificate? Or this ...
5
votes
3answers
1k views

Qualys SSL Scan weak cipher suites which are secure according to ciphersuite.info

I am testing my application SSL configuration in Qualys SSL Labs and as a result, I have this cipher suites labeled as weak: But according to https://ciphersuite.info/ all of these cipher suites are ...
1
vote
1answer
161 views

Is it possible to crack a laptop's encrypted hard disk?

In a talk about a lost or stolen laptop, it is said that: even with hard drive encryption, eventually they can crack these secrets But strong encryption is practically impossible to break. For ...
0
votes
1answer
120 views

Did The Wire invent the “Jump 5” cipher?

N.B. Asking this here instead of Movies.SE because I'm wanting to know about the cipher itself and any history, which this site is more suitable for. In S01E05 of The Wire, at around 45:00, it's ...
0
votes
1answer
129 views

Help identify a simple, reversible cipher/encryption algorithm [duplicate]

I'm trying to help a small business transition out of an obsolete, obscure piece of software, and app support is, unfortunately, non-existent. To fully export the data for the new system, I need to be ...
0
votes
0answers
36 views

TLS client does not drop connection even when there are no suitable ciphersuites in the server ciphersuite list during handshake

I have two Windows systems, and I want to establish an encrypted TCP/IP communication between them. Specifically TLS 1.2 or TLS 1.3. I have configured in both systems the list of allowed ciphersuites: ...
-1
votes
3answers
201 views

how do i find the number of possible keys / password to decrypt a plain text

I would like to know if there is any way to recover the plain-text of a message that's been encrypted with 55 rounds of the Caesar cipher, with a different (independently chosen) key for each round; I ...
1
vote
2answers
203 views

OpenSSH: Meaning of cipher with email address @openssh.com

When using OpenSSH server (sshd) we specify allowed ciphers, host key algorithms and MACs. Some of those ciphers have an email address appended, for example aes256-gcm@openssh.com as opposed to aes256-...
0
votes
2answers
401 views

Remove less secure ciphers from WHM by decrpyting different convoluted references to the same ciphers

I have previously removed less secure ciphers from WHM (Web Host Manager) however it has been a while and I want to learn how to fish, not be handed a fish. The trouble seems to stem from the fact ...
5
votes
1answer
480 views

Why is the BCrypt text “OrpheanBeholderScryDoubt”

I'm looking for a reference about the weird initial BCrypt text "OrpheanBeholderScryDoubt" Why was this string used? Would using 192 zeros or ones not have worked well in practice for some reason? ...
1
vote
1answer
146 views

What is a LUKS cipher-name “@”?

In analyzing the LUKS header on an encrypted volume, the cipher-name field shows a single-character = '@'. What does that mean? The LUKS On-Disk Format Specification originally published by Clemens ...
1
vote
1answer
787 views

What is the difference between “cipher” and “encryption”?

It seems as if they are either synonyms, or cipher was an older term for when they directly translated the same number (or almost same number) of "encrypted" characters into the same number of ...
0
votes
3answers
234 views

How would anyone ever break even this basic, amateurish cipher/encryption scheme?

This question was prompted by a long Wikipedia session with me reading tons of articles on cryptography, causing far more questions than it answered. Let's say that I and another person know each ...
1
vote
1answer
162 views

What exactly was “'dotty' and 'dashy'” Morse code?

During early World War I (1914–1916), Germany briefly experimented with 'dotty' and 'dashy' Morse, in essence adding a dot or a dash at the end of each Morse symbol. Each one was quickly broken by ...
1
vote
0answers
569 views

Disable vulnerable cipher suites

As a part of my learning, I installed OpenVAS into one of our Ubuntu test servers and scan the said server. I have the results and I wanted to remediate the findings as part of my learning the Linux ...
2
votes
1answer
436 views

Why does the NodeJS Crypto docs use CBC instead of GCM for RSA key-pair?

I have read that GCM is almost always more secure than CBC when implemented correctly. However, in the documentation of NodeJS, CBC is being used as an example instead. The key-pair will be stored ...
0
votes
1answer
222 views

What if the attacker tamper the IV used in the block cipher CBC mode?

I am a newbie to block cipher and when learning the CBC mode, I start to understand that an IV is being used in this mode and also will be transferred to the message receiver. So here is my question,...
1
vote
1answer
144 views

TLS key exchange and certificate subject public key clarification

This question is similar to this one, so let me elaborate what I'm struggling with. I want to get the length/strength of the key used by the server during the key exchange and authentication, i.e. ...
1
vote
0answers
277 views

Openssl using the cipher parameter result in handhsake failure

When i use Openssl to connect to facebook.com I see 'ECDHE-ECDSA-AES128-GCM-SHA256' ciphersuite used. openssl s_client -connect www.facebook.com:443 SSL handshake has read 3280 bytes and written 373 ...
0
votes
0answers
33 views

Can someone explain the significance of Certificate Signature algorithm in the selection of Cipher suite in a TLS communication? [duplicate]

Can someone explain the significance of Certificate Signature algorithm in the selection of Cipher suite in a TLS communication?
2
votes
1answer
232 views

3DES supported in application although disabled in Windows

Can users actually use the 3DES cipher to connect to a Tomcat web server, if the 3DES cipher has been disabled via registry keys in Windows: HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\...
0
votes
0answers
34 views

Help me to identify what type of string it is? [duplicate]

70373f65f945e5184dcb42793cbe2cddb34248ef172b7ddb5e27467fd8d76314ea8bdeb19226687ac0ca01e646dbe8fdb4dfb2d6816f54b9b500639ac6c3bf056fbd4c45a246bbe66e6fd0ce3730801716b12fff942207933e1bb6386806d476ade6f5b1 ...
0
votes
1answer
923 views

How do I get the list of cipher suites supported in a specific TLS version?

Is there any cipher suites supported in one TLS version and not supported in the other? If yes, then is there any documentation that talks about the cipher suites supported in each TLS or SSL versions?...
0
votes
1answer
735 views

Deciphering ciphertext with an unknown key and algorithm [closed]

How can I get started on understanding how to decipher this ciphertext when I don't know the algorithm or key used? TDcbY xqCa NeAA OsWMirK FNFOm bYRUYAkxl,  tqwl  axZU  XTaLrBSFv OI G vWjBZyqhz.  ...
2
votes
2answers
1k views

Is there any CBC based ciphersuite which are secure for known attacks like LUCKY13?

If you select the modern profile in https://mozilla.github.io/server-side-tls/ssl-config-generator/ , you can see it recommends to enable following four cipher suites also. ECDHE-ECDSA-AES256-SHA384 ...
-2
votes
1answer
215 views

aes-128 refers to the block size, key or both

What does the number used in cipher suites next to the symmetric encryption algorithm reefers to? Does it mean each block is divided into 128 bit blocks, the key size or both ?
19
votes
1answer
10k views

How do I know which cipher suites can be disabled?

I have just performed a test on my personal webiste via SSLlabs.com and I'm apparently supporting some weaker ciphers. I've managed to improve several settings (like CAA), but I'm getting stuck at the ...
3
votes
1answer
200 views

How to filter ciphers based on ssl certificate?

I have many ssl certificates. On one of the certificates I run the command openssl x509 -in cert.pem -text -noout it shows: Signature Algorithm: ecdsa-with-SHA256 Public Key Algorithm: id-...
1
vote
3answers
487 views

Losing the Initialization Vector in Cipher Block Chaining

I have written a message and encrypted it using cipher block chaining. What will happen if the receiver loses the Initialization Vector, or doesn't receive at all?
5
votes
1answer
165 views

Do ciphers and encoding schemes make passwords more secure?

I recently came across a tech professional advising a user to take some plaintext of their choice, run it through one of these ciphers, convert it to Base64, and then use the result as their master ...
0
votes
1answer
196 views

What's the difference between `aes-128-cbf` and `aes-128-gcm`?

We often hear of AES-128-CBF and AES-128-GCM, but what's the difference between them?
-1
votes
1answer
160 views

What's the meaning of cipher's `IV Length`?

What's the meaning of IV length? there provide several stream ciphers, what's the meaning of IV Length? Name Key Size IV Length aes-128-ctr 16 16 aes-192-ctr 24 ...
0
votes
1answer
96 views

For a cipher school challenge I need help breaking this cipher [closed]

[CIPHERTEXTSTARTS]HI wsndtonInehbihs if at t iyoncniegtrf .e noionbpni y,iu.w ahoui hs hroyh!euecsy m.ot ew hrc hb;ntsresnmdma ipMsat ln ts , ryiceg ensh c n byr t k t oe de uhw stiytoer s ...
0
votes
0answers
33 views

Whether cipher suites is related to public key certificate? [duplicate]

I want to use TLS version 1.2 and Authenticated Encryption with Associated Data (AEAD). Can a public key certificate obtained from a certification authority specify which of the ciphers I can use? ...
1
vote
1answer
220 views

OpenSSL Padding Oracle. Specific Ciphers on apache2 seems a little limited

I've seen a lot of articles giving the official explanation on how to prevent OpenSSL Padding Oracles, Usually all of them state that its CBC cipher suites that leave you vulnerable. The following ...
2
votes
1answer
1k views

What is a “non-stitched” ciphersuite?

From the OpenSSL Security Advisory - 0-byte record padding oracle (CVE-2019-1559) In order for this to be exploitable "non-stitched" ciphersuites must be in use. What is a 'non-stitched' ...
0
votes
1answer
106 views

Cipher that does not give confirmation whether decryption is successful

I was reading this question where the author wanted to know whether layered encryption would be better than a long password. The answers to this question all said the same thing: It would be easier ...
-6
votes
1answer
3k views

How to disable obsolete/insecure TLS_RSA ciphers to harden Chrome? [closed]

Multiple vulnerabilities have basically obsoleted TLS_RSA, CBC and QUIC implementations. February 9, 2019: "Seven researchers from all over the world found --yet again-- another way to break RSA ...
0
votes
0answers
25 views

choosing a cipher suite for sending a simple email on embedded systems

Anybody have any input/feedback on this. I've been given the task of researching how to send a 'secure' email using SSL on an embedded system with very limited RAM and Flash ROM. The email is very ...
7
votes
3answers
3k views

What are the 'P' values in some cipher string?

Most of the cipher strings I see are in the format: TLS_DHE_RSA_WITH_AES_256_CBC_SHA256 TLS_DHE_RSA_WITH_AES_128_CBC_SHA256 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 ...
0
votes
1answer
568 views

Why are ciphers using DSS being offered when using DH+AES:!DSS?

When I run the following command on Windows 10 with OpenSSL 1.0.2p installed I receive a curious result back (Formatted for readability): openssl ciphers "DH+AES:!DSS:!aDSS:!aNULL" DH-DSS-AES256-GCM-...
4
votes
2answers
1k views

Apache TLS with only ECDHE-RSA-AES128-GCM-SHA256 enabled

Is there anything against this TLS-configuration in Apache: SSLProtocol TLSv1.2 SSLCipherSuite ECDHE-RSA-AES128-GCM-SHA256 There are lots of examples that use a more complicated setup, but I believe ...
3
votes
2answers
3k views

Cipher Suite TLS 1.2 - Weak in OHS

I am trying to correct weak encryption in TLS, by doing a test in SSL Labs, it throws weak encryption in the following chpher suite: Current Configuration: SSLCipherSuite HIGH:!MEDIUM:!LOW:!aNULL:!...
4
votes
2answers
211 views

How are ciphers related to cryptographic algorithms like DES or AES?

It looks like I am having a terminology issue here. In cryptography, we have stream ciphers and block ciphers. I understand their difference. We also have cryptographic algorithms like AES (Rijndael). ...
1
vote
1answer
4k views

Why would TLSv1.0 TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA still be used?

First, I may be asking a dumb question. I am trying to learn, so please, take it easy on me. Second, if this is not the right place for this question, or you can link me elsewhere, please tell me/ ...