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.

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OpenSSL & TLS1.2 with aes-cbc and initialization vector

I'm trying to manually decrypt DTLS traffic using OpenSSL and TLS 1.2. The cipher suite im using is AES256-SHA256 as listed here. Im able to decrypt the packets with the key that the server and the ...
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2answers
27 views

OpenSSL Signature different each time

I have a file that I am generating a signature for using OpenSSL, and each time I generate the signature, it is different to the last time. ...
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0answers
24 views

Degrade in performance with SSL_OP_SINGLE_ECDH_USE?

We have used SSL_OP_SINGLE_ECDH_USE when setting up our SSL_CTX . This seems to be causing a degrade in performance. I'm not able to find proper documentation for it except that it generates new ...
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1answer
69 views

How is SSL secure?

if the client and the server need to exchange keys and I can sniff it, wouldn't I be able to decrypt the data transported?
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1answer
42 views

How to correctly encrypt data with proper authentication using AES-256-CBC in php?

I have been using the openssl function for encrypting data with AES-256-CBC in php. I have been able to encrypt it using an unique IV (by generating with openssl_random_pseudo_bytes)for each new ...
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2answers
134 views

Recommendation for lightweight algorithm for partial message encryption

I have designed a specific client and server program, which sends a file from client to server in 32k chunks. I want to encrypt only part of the data. More specifically: in each 32k chunk passing ...
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2answers
61 views

Are low security curves for ECDSA not supported?

I am working in a very bandwidth restricted environment, and we are looking to implement ECDSA digital signatures. Although they are no longer recommended, we might be looking to use curves that are ...
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0answers
14 views

Are the ECDSA public keys of a stable/fixed length relative to curve size? [duplicate]

I am working in an environment with strict bandwidth requirements, and we need predictable bit lengths of the stuff we send. We need to broadcast ECDSA public keys, and we are using OpenSSL to ...
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1answer
52 views

Can I shorten the large ECDSA public key output file from OpenSSL?

I am working in a very bandwidth restricted environment where I from time to time have the need to distribute public keys. The distribution happens in bit format, so there is no need for encoding, at ...
4
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1answer
53 views

Is it secure to use hexadecimal data for IV instead of raw binary?

Is it safe and secure to use a function like bin2hex (which converts binary data to hexadecimal) on the binary output of functions like ...
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0answers
18 views

How to extract public key from attestation certificate to use it for signature verification? [migrated]

I want to extract the public key from a certificate to verify a given signature (to answer my own question in relation to the registration part). I've tried ...
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0answers
9 views

Can I extract R and S from an ECDSA signature in bit form, and vica versa? [migrated]

I have searched the forum and found related information, but not answer to this question. I am working in an extremely bandwidth-restricted environment, in need of creating as small ECDSA signatures ...
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1answer
30 views

setting the MGF hash to a different value other than the regular hash with openssl for PSS signatures

In PKCS1's Probabilistic Signature Mode you have the Hash and the MGF Hash. Both appear to be, by default, sha1, with the OpenSSL CLI client, however, I can change it to sha256 with the following: ...
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1answer
38 views

Limit the length of AES encoded output to certain value

First let me be clear upfront that am not Crypto expert. I'm having a problem where I will have to use NFC card. Now given the limitation of NFC cards memory sizes, I will need to constraint my system ...
1
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1answer
43 views

How to store keypair generated by RSA in a textfile?

I'm trying to write an encryption decryption program using Openssl-RSA. There are only two operations. User stores the data and retrieves it whenever he needs. To decrypt something, we need the ...
2
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2answers
123 views

Different tools return different ciphertext value for equal input

I have a Luna G5 Safenet HSM and I want to encrypt a text file containing testtest with 3DES-ECB algorithm. So in the first step ...
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1answer
55 views

How to verify CA certificate from Yubico with openssl?

I'm going to verify the CA certificate from Yubico. I copied the whole certificate from -----BEGIN CERTIFICATE----- to ...
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0answers
94 views

How to verify a signature with openssl methods from the ECDSA class?

I'm trying to verify my signature like I explained in my question before. But I have some problems to program my own verification without the verify methods of openssl. Therefore I'm going on to use ...
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0answers
37 views

How to check the signature without the predetermined function in ECDSA from openssl?

I'm developing a client for a two-factor authentication in Qt/C++ under openSUSE 13.2, 64bit. I've got the FIDO U2F Security Key from yubico/fido. I'm using the classes from openssl, in particular ...
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0answers
56 views

Why is SSL/TLS so complicated?

I'm new to SSL/TLS and I'm staring as a new security researcher. It appears to me that SSL/TLS protocol is needlessly complex for arriving at a shared secret. The complexity results in so many bugs ...
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2answers
669 views

Would it be better to split a file and then encrypt, or vice versa?

Assuming that you're 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 ...
1
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1answer
51 views

SSL implementation in windows? [closed]

SSL (Secure Socket Layer). windows Webbroswers ( Chrome, Mozilla, Edge, explorer ) are using which winapi set to Encrypt and Decrypt Data. SSL is asymmetric encryption. So which Api set is being used ...
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0answers
58 views

Fingerprint RSA public key in PKCS1 format

I can't find anywhere details on how to fingerprint a public RSA key in PKCS1 format. There are a lot of examples on the internet on how to fingerprint an RSA public key in openssh format using ...
3
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1answer
93 views

Can a billion elliptic curve keys be generated on a laptop in less than an hour?

I want my application to generate an EC key pair. The first four bytes of the sha256 hash of the public key should contain a known IP address. As hashes are one-way functions, I need to brute force ...
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0answers
54 views

MD5 SSL Collision Attack

I want to create fake certificate for test purposes. I have read about the http://marc-stevens.nl/p/hashclash/index.php project but I am unable to understand the two files that I have to put as input ...
4
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1answer
64 views

How to exctract ECDH parameters from an OpenSSL-generated $G$?

I'm using ECDH for generating ECDH public parameters (p,a,b,G,n), I try to get this values using openssl ecparam -in cert.pem -text -noout For ...
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1answer
482 views

generate RSA public key having public modulus and exponent [closed]

i want to generate an RSA public public key file using openssl (or other tools) having public modulus and exponent, so i can use it later to encrypt files i have this: ...
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1answer
122 views

Why a key pair is used in OpenSSL ECDSA_sign or ECDSA_do_sign instead of only private key ?

If the digital signature in ECC (ECDSA) is made using a private key, why is the OpenSSL library using ECKEY pair as an input parameter instead of the private key only ?
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1answer
153 views

How is OID 2a 86 48 86 f7 0d parsed as 1.2.840.113549?

I saw that an RSA key, created by OpenSSL, contains the following HEX string: 2a 86 48 86 f7 0d 01 01 01 that HEX string gets interpreted as Object ID: 1.2.840.113549.1.1.1 It is obvious ...
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0answers
354 views

Decrypt using OpenSSL produces packing errors

I am receiving an encrypted file and it's key from a partner. The Key has itself been encrypted using our Digital Certificate Public Key, though I don't know exactly how. The partner has instructed me ...
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2answers
163 views

How to derive a symmetric key from ECDH shared secret?

I am trying to implement the internal primitives of ECDH. Currently I'm able to multiply the receiver's public EC point with the sender's private key to arrive at the shared EC point. Next step is to ...
2
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1answer
123 views

OpenSSL ECDH key exchange mechanism

I am using FIPS based OpenSSL module for encryption of sensitive data for my desktop socket server and client applications. I am using ECDH for key agreement.The keys public and private pair is ...
3
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1answer
60 views

Size of encrypted AES CEK in CMS block

When I run openssl cms -encrypt -aes256 -in sample.der -out wrapped.der -outform DER -recip ecc.crt -keyopt ecdh_kdf_md:sha512 the part of the CMS output which ...
3
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1answer
114 views

Safety of AES ECB when used with openssl_seal function

I'm trying to use PHP to encrypt files with a public key. I'm using the function openssl_seal that "encrypts data by using RC4 with a randomly generated secret key." RC4 is considered unsafe so the ...
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1answer
47 views

Certificate for the public key

I am new to Network Security and learning about various security features like Diffie-Helmann and others. I understand that the Public key send by the server to the client needs to certified that it ...
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0answers
80 views

seemingly common error with OpenSSL and creating a PKS no certificate matches private key [closed]

I have a JKS store and export a signed cert (from the CSR generated in the store and signed) and the private key - I convert to PEM and attempt to generate a PKS from these two files. openssl.exe ...
1
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1answer
216 views

Supersingular Isogeny Key Exchange Software [closed]

Are there any optimised implementations of the Supersingular Isogeny Key Exchange by Defeo, Jao, and Plut. It seems like this would be a great drop-in replacement for Diffie-Hellman in both OpenSSL ...
1
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3answers
52 views

“Strict” software for playing and learning with private and public key

my question is just for teaching/learning practice and I think it's not meaningful for the real world. I've played with openssl a lot but from my understanding it's somehow not strict in the format ...
0
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1answer
141 views

How openssl padding for AES cfb IV?

From a few documents I have read and a few questions about padding here, I think if I passed a encrypted text fewer than BLOCK SIZE, openssl would pad it per PKCS7. And use that padded encrypted text ...
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1answer
688 views

What do I use as the encryption key and initialization vector in AES cfb128

I'm writing a program that can encrypt a file using AES cfb128 (using Openssl and C++). The scenario of the program is this: Person A visits computer, encrypts a file they make, takes away a key ...
0
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1answer
785 views

Decrypted RSA 64 bit encryption using modulus and private exponent. Got gobbledygook [Verify] [closed]

As part of an experiment, I was given a .enc RSA (encrypted) file that was most likely generated using openssl. I had the public key, I factored it, obtained the private exponent, and decrypted the ...
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1answer
3k views

How to decrypt a '.enc' file that has been encrypted with RSA using a public key? [closed]

While solving a CTF challenge online, I came across a situation where I needed to decrypt a '.enc' file that has been encrypted using someone's public key. The ...
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1answer
160 views

Openssl library problem

I'm using openssl library and I've a problem with RSA_private_encrypt() and RSA_public_decrypt(). I'm using a key size of 256 bit with no padding of the input message. I've noted that when my input ...
0
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1answer
201 views

Repair AES-128 decrypted file

I decrypted a file which was encrypted with OpenSSL and AES-128 with the wrong password. Before I noticed it was the wrong password I removed the original file. Is there a possibility to reproduce the ...
3
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1answer
87 views

Is this JS library using openssl genrsa -rand improperly?

pem, a JS wrapper around openssl, has the following code in it: var params = ['genrsa', '-rand', '/var/log/mail:/var/log/messages', keyBitsize ]; Am ...
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1answer
382 views

Why don't PyCrypto and M2Crypto produce the same result as OpenSSL here (AES-128 ECB)

If I run the following, for openSSL: echo -n "0123456789abcdef0123456789abcdef" | openssl aes-128-ecb -nosalt -nopad | xxd and enter the key "YELLOW SUBMARINE", ...
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1answer
376 views

ECC considered secure in OpenSSL?

If I perform the following command: openssl ecparam -list_curves using my OpenSSL version (1.0.1f), it spits out the following supported curves: ...
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1answer
92 views

OpenSSL encrypted text length

OpenSSL block ciphers return length of the text as output of the encryption (envelope_seal()), and If I have to send the length over network, I append the length ...
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4answers
1k views

Secure way to encrypt and decrypt a folder on Mac or Linux? [closed]

I am looking for a way to securely encrypt files on Mac and Debian. OpenSSL comes pre-installed on Mac OSX and Debian/Ubuntu. Therefore, is this a safe/recommended way of encrypting individual files? ...
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0answers
55 views

emulating progressive encryption with RC4 / OpenSSL

PHP's OpenSSL bindings do not support progressive encryption by default. ie. if you do ...