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Questions tagged [openssl]

OpenSSL is an open source implementation of the SSL and TLS protocols. Questions about how to use the OpenSSL tools and libraries are usually better asked at Stack Overflow or Super User.

2
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1answer
253 views

SSL - encrypt with private key and then with public key?

Say there are 2 sides that wish to communicate: side A and side B. Let's say we are looking at side ...
0
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1answer
21 views

How to check a signed CSR with openssl?

I just learned that a CSR can be signed. See this Why is a CSR signed and which key is used for signing? I tried to check the csr with below openssl command, but failed with errors "139942025398160:...
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0answers
19 views

Verify XML file signature (xmldsig)

I've gotten an XML file with an enveloped signature inside it. Is there any way I can validate that file, with seeing what is inside that signatures as well? The file contains a ...
0
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1answer
47 views

Unable to reproduce correct signature data

"Skatteetaten" is the Norwegian tax authority. We're currently trying to implement signing of messages for digital cash registry systems and i'm not able to reproduce the desired signed data. Went ...
0
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1answer
33 views

When a program using openssl library is using a certificate, does the server check if the issuer(s) are still valid

If I have a program acting as TLS server with a certificate signed by a CA, if one of the issuers in the chain becomes invalidated or the date expires, then how does the program using the certificate ...
2
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1answer
25 views

Are Authenticated Encryption ciphersuites supported in legacy TLS versions older than TLS 1.2?

I have read in a paper that Authenticated Encryption (by this I mean those that support GCM mode or ChaCha20 ciphers) are not supported in versions older than TLS 1.2? I could not confirm this as ...
1
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1answer
42 views

Simulation of Chosen Plaintext Attack on CBC, Predictable IV with OpenSSL

I would like to simulate the CBC IV attack where the IV is predictable. It's described in the answer to this question: chosen plaintext attack on CBC, predictable iv (Only "Yes" and "No" are valid ...
2
votes
2answers
165 views

The attacker model of the Lucky13 attack in TLS

Lucky13 is a timing attack against the MAC in the CBC MAC-then-encrypt ciphersuites. In the attack's page: The attacks involve detecting small differences in the time at which TLS error messages ...
1
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0answers
48 views

Encrypt multiple files with OpenSSL securely [closed]

I wish to encrypt potentially gigabytes of data on my pc, and I wish to be able to decrypt and use those files. However, I am a noob, so bear with me. My idea is to use ...
2
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1answer
73 views

Decrypting AES256-CBC with wrong encryption key

Using OpenSSL library is there any chance that decrypting AES256-CBC encrypted data with wrong encryption key will succeed without an error? Asking this because I have read somewhere there is 1/256 ...
3
votes
3answers
377 views

What is different below two Ciphersuites?

I have two questions; I need an explanation for the differences of below two cipher suites. How do they work with SSL/TLS protocol? (my main concern first one doesn't have '...
3
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1answer
268 views

Why can't decrypt with OpenSSL if salt changed (for CBC and ECB)

A file encrypted with OpenSSL (with, for example, AES 256-bit mode CBC) using the Linux command openssl enc -aes-256-cbc -in texte -out encrypted_texte -k password ...
1
vote
1answer
58 views

What is the encoding protocol for passphrase protected RSA private keys?

What is the protocol used to encode an RSA key protected with a passphrase? If I generate an RSA key with ssh-keygen -t rsa -b 4096 and do: ...
2
votes
1answer
215 views

Is this a good PHP encryption Strategy?

I'm writing a multi-tenant application that interacts with a couple of different APIs on behalf of each customer. Obviously, we need to store private keys for these various different APIs in the ...
1
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1answer
220 views
2
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1answer
199 views

X25519 - why openssl shows 253 bits?

When using ECDHE with Curve25519 with openssl: Server Temp Key: X25519, 253 bits I thought when we use X25519, it use 256 bit key. Why openssl shows the server temp key as 253 bits?
3
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0answers
45 views

How to see Diffie Hellman private key used during negotiation? [closed]

I used OpenSSL s_client to connect to a test server. Because OpenSSL generated client side private DH key, I think there will be a way to show the private key or ...
2
votes
1answer
52 views

The “openssl genrsa” command only generates a private key?

The command : openssl genrsa -out RootCA.key 4096 generates a single file named RootCA.key. When I open the file, it only contains the private key. Then ...
1
vote
1answer
61 views

Question about OpenSSL testing for FIPS 186-4 and using BN_generate_prime_ex

I am working on testing my implementation of OpenSSL using the CAVP 186-4 RSA Validation System (RSA2VS). There are tools under openssl-fips-2.0.16/test and I am working on modifying fips_rsagtest.c ...
1
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1answer
57 views

Question about using BN_rand() [closed]

I am working on a project and I'm noticing a peculiar behavior that I was hoping someone could tell me if it is correct or not. I have a program that is trying to generate some random numbers using ...
-1
votes
1answer
38 views

I am new to digital certificate 509V3 concept. can some one please clarify the below points [closed]

I am using RSA 2048 with SHA 256 primitive in certificate: How to verify the user certificate n + 1 with Root certificate n? why it is required to perform Certificate chain verification? How to ...
2
votes
1answer
26 views

Does the server signs message body after ssl handshake?

So after SSL handshake the master secret is used to securely transfer data encrypted using symmetric cryptography. My question is simple: after SSL handshake, when the server (for example my bank) ...
0
votes
1answer
96 views

What is the difference between: ecdsap, ecdsak, and ecdsab in the output of “openssl speed”? What do the letters P/K/B refer to?

openssl speed tests the speed of different protocols on your computer: ...
1
vote
3answers
466 views

Differences between DSA and RSA Algorithms

Despite having learned much related to RSA and DSA, I cannot understand their differences. Can anyone tell me at least 4-5 differences between these algorithms? I have just used them for two-factor ...
1
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1answer
83 views

Clarifications regarding ciphers and Nmap scan

I'm running the below Nmap command to test the strength of the cipher suites I have used in my host nmap -sV --script ssl-enum-ciphers -p 443 <host> The ...
0
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2answers
499 views

Appropriate key for AES 256 GCM

I am updating a system that has Rails' OpenSSL on one side and Python's cryptography.io on the other. The Rails side has to generate keys for the AES-256-GCM and here are two methods that appear to ...
2
votes
1answer
133 views

Do aes_256_gcm IVs just need to be unique for that key?

I'm using GCM (via openssl's EVP_EncryptInit_ex(ctx, EVP_aes_256_gcm(), NULL, NULL, NULL))). The IV's default length is 12 bytes. It says that the IV must be ...
1
vote
0answers
37 views

Benefits of using SSL certificate over a raw key pair for non-browser use?

For applications not involving CA signed certificates – or web browsers for that matter – it would seem to be easier to use a raw key pair if possible, rather than deal with potential formatting ...
1
vote
1answer
659 views

symmetric AES encryption with php produces different result than openssl MacOX

I need to make a simple very basic encryption with AES 128 ECB mode. The idea is to generate a cryptogram, code it in base64 and then decipher that text from a web service in php to process its ...
1
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0answers
152 views

openssl command line equivalent of AESWrap? (defined in RFC3394; use in AmazonS3 Client Side Encryption of datakey wrapping) [closed]

when dealing with S3 Client Side Encryption, it's using "AESWrap" (defined in rfc3394) algorithm to encrypt the data-key; I'm trying to play with openssl command line to see if it's possible decrypt ...
0
votes
1answer
55 views

Link between openssl 'req' command and 'unable to get local issuer certificate'?

I was using the following command to build a self-signed certificate after creating a private key: ...
2
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1answer
62 views

CAs are pre-loaded on the system, but how is it able to get intermediate certs?

I have the following X509 certificate: ...
0
votes
1answer
368 views

What is the Peer Signing digest on an OpenSSL s_client connection?

For a little background, I am trying resolve an issue with an ISAM (reverse proxy) appliance not being able to connect to a server due to it failing to complete a TLS connection. A server that is ...
0
votes
1answer
340 views

Discrepancy between 3DES in OpenSSL and PyDES [closed]

I'm trying to encrypt some data using triple DES ECB, but I get a discrepancy between OpenSSL and the pyDES library I'm using. When trying to get a KCV value, I'm using a file consisting of 8 bytes ...
0
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0answers
54 views

Using OpenSSL to emulate LTO 4 tape encryption

I have a mix of LTO 4 and LTO 3 tapes I would like to encrypt data on to. LTO 4 has built in encryption - load they key into the drive, and it handles the AES-256-GCM encyption transparently. LTO 3 ...
0
votes
1answer
231 views

Best method to achieve authenticated encryption with openssl

Problem I want to send a plaintext document between from myself to someone else over an untrusted link. I want to firstly stop third parties from reading the document, I want the receiver to be able ...
0
votes
1answer
315 views

Which cipher to use with openssl for shortest output?

I'd like to encrypt my 12-24 words seed for my bitcoin wallet with openssl command line tool to be able to have it with me on paper without the risk that somebody could use it Which cipher should I ...
1
vote
1answer
166 views

How to select elements randomly from a multiplicative group Zn*

I am working on a problem in which I have two large safe primes say p and q randomly selected each of 512 bits. I have generated ...
0
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1answer
2k views

Proper implementation of AES-256-GCM with PHP OpenSSL [closed]

I am really lost in this subject, I find it hard to get any reliable documentation on the subject that is a bit friendly for beginners like me. So I apologize in advance if this question would sound ...
1
vote
1answer
229 views

How to sign a CRL file if I have offline keys?

I am generating a CA for internal use. When generating a CA, the best practice I have observed is to keep the root CA offline and emit an intermediate CA certificate that will in turn emit the end-...
-3
votes
1answer
55 views

How to find out whether RNG is reliable or not , when we generate RSA keys from OpenSsh?

I just want to check whether the entropy supplied is good enough for key generation or not .
0
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1answer
313 views

RSA Key Differences (OpenSSL CLI vs. OpenSSL/ssl.h C function)

So, I am sitting here trying to figure out what is happening and why two keys are different in such a vast manner. I've created two key pairs, one key pair with the OpenSSL CLI commands on an Ubuntu ...
0
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1answer
389 views

how to validate cert when signed cert has authority key id but signing cert doesn't?

Say I have the following signing cert: ...
1
vote
1answer
183 views

OpenSSL - creating random elliptic curve and measuring performance

I want to generate random elliptic curves (over $\mathbb F_p$ and $\mathbb F_{2^m}$) using OpenSSL, that's my task. At first curves over $\mathbb F_p$. Now I am able to generate prime $p$, $a$ and $b$...
1
vote
1answer
149 views

Obtain Information about hash algorithm from ECDSA public key

I have an ECDSA Public Key in DER Format. I viewed the file in an ASN1 Editor and there's the OID 1.2.840.10045.1.1 whose superior (...
1
vote
1answer
370 views

How does HTTPS transfer the symmetric key?

How is the server's public key used to encrypt the symmetric key in a way so that only the sever's private key can decrypt the cipher? The client uses the server’s public key to encrypt the ...
-1
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2answers
2k views

Decrypt AES key with RSA public key

So here's my problem: I have 3 files. One is ciphertext.enc, which is a text encrypted using AES 256. The second one is ...
0
votes
1answer
219 views

Changing password hash and iv on (successful) user login

I've implemented a system for my login page (with php) that will update the password hash and initialization vector (for openssl) on each login. So essentially, every time the user successfully logs ...
0
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2answers
4k views

How to encrypt a string using RSA public key only? [closed]

I have been given the following public RSA key: ...
5
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2answers
448 views

Security of non-standard use for AES-256-CTR?

I have a string secret that I would like to encrypt for storage in a Yubikey's second slot. These slots can be configured to store up to 38 characters that are later "typed" by the USB device acting ...