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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.

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81 views

How to configure a client browser cert to be authenticated by a server?

I currently am being asked to partake in a strange authentication format while working with a client, and was hoping for clarification. The client is using HTTPS with client certificate ...
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1answer
584 views

openssl sha1 message digest not matching with NIST vector input?

When I call openssl sha1 from the command line echo "00" | xxd -r -p | openssl dgst -sha1 the output I am receive is ...
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1answer
274 views

Security of RSA Keys in OpenSSL

So when genrating a private key / or key pair in OpenSSL ther is the -nodes tag to deactivate the encryption of the private key . i looked it up and It means "no DES" . So no DES is used . Why is DES ...
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0answers
400 views

Safe initialization vector when using openssl_encrypt [closed]

Is php's bin2hex(random_bytes(8)) safe for an initialization vector when using openssl_encrypt()? ...
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2answers
584 views

Best approach for storing private key

I'm working on a web service application which uses a self signed certificate. I apologize up front if this turns to be a dumb question. When using openssl for generating private key, it reveals (as ...
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1answer
781 views

Correcting Improperly Formatted EC Private Keys [closed]

We are currently generating a secp521r1 key as follows using cryptography for Python: ...
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2answers
5k views

Anatomy of an RSA private key

I'm learning about OpenSSL and public key infrastructure and am curious about the structure of an RSA key and how it's related to its corresponding public key. I can generate a private RSA key with ...
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0answers
699 views

Why is a “Signed Digest” different from a “Digest which has been Signed”

I want to understand why creating a signed-digest of a file is different from creating a digest and then signing it. IE. If I do the latter, the verify fails. Here is my test script. Can someone ...
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1answer
401 views

Can you explain what is whitelisting in TLS False Start

In TLS clinet false start mechanism, the standard says the following: The symmetric cipher defined by the cipher suite negotiated in this handshake has been ...
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1answer
7k views

Encryption, Decryption using OpenSSL

How to use OpenSSL in windows for encryption and decryption ?
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3answers
1k views

Explanation of openssl ciphersuites

I'm looking for a detailed explanation of the ciphersuites available in openssl. openssl already offers the ciphers command which can be used to output, for example, the following: ...
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1answer
430 views

OpenSSL: Call X509_verify_cert on a certificate with OIDs unknown to openssl [closed]

I have a DS and a csca certificate that contain special OIDs from the BSI. They are: ...
2
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1answer
318 views

Clinet's nonce in TLS

In TLS, both client and server send nonces int heir hello messages. How the server identify whether the client hello is replayed or not? does the server maintain cach of previous nonce? for how long? ...
3
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1answer
614 views

What's the ASN.1 structure of ECIES encryption result? [closed]

I got a ECIES encryption result and a publickey,the publickey after decoding to ASN.1, I obtained the following: ...
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0answers
277 views

Asymmetric vs symmetric encryption

I am a beginner learning about encryption and I would like to ask a few questions, hoping this is the right place to ask, so please bear with me. We have Alice and multiple clones of Bob. Only Alice ...
2
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1answer
277 views

ClientKeyExchange in static DH

I am confused about the content of ClientKeyExchange in case if the key-exchange is static DH. The TLS 1.2 standard says under section 7.4.7 in https://tools.ietf.org/html/rfc5246#page-57: If the ...
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1answer
260 views

CBC Padding Oracle in SSL3. Why only in SSL3 not in TLS1,TLS1.1, etc

I read about PODDLE attack which downgrades the TLS version to SSL 3.0 to exploit CBC padding oracle attack. I looked at the specs for TLS 1.1 And found CBC is still used in its ciphersuites. Why is ...
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1answer
6k views

What is the correct format for a CRLF in a SSL certificate's pem

Currently I am working with SSL certificates inside a Ruby on Rails application. I am storing the certificates in a database along with the corresponding dhparam, and chain. At some point I want to ...
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1answer
308 views

CTR vs CBC cycles per byte with OpenSSL EVP

I did some benchmarking using the EVP calls of OpenSSL in C, for CBC and CTR encryption/decryption. (1) : I got 3.2 Cycles/Byte for CBC encryption. (2) : I got 0.7 Cycles/Byte for CBC decryption, CTR ...
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1answer
1k views

What is actual difference between POODLE and BEAST?

I know that both attacks are based on the fact that the cipher used for communication is block cipher with CBC mode of operation and that is vulnerable because of predictable IV. Furthermore the ...
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2answers
4k views

How does OpenSSL know if a decryption failed? [closed]

I have a file full of garbage, random data, and I encrypt it with AES256: openssl -in myfile -out encfile -aes256 -pass pass:abc123 If I try to decrypt it with ...
12
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1answer
2k views

Why do crypto tools display key components in such an unusual format?

openssl x509 (v1.0.1f) displays public key moduli as arrays of hex-encoded bytes, 15 columns wide, starting with a leading 00:: ...
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1answer
177 views

Can we use witnesses generated by OpenSSL's Rabin-Miller primality test to help factorization?

If I have a 2048 bit value used as the modulus for an RSA exchange, and OpenSSL's BN_is_prime() has determined that that value is not a prime, does that mean that OpenSSL has found a strong Rabin-...
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1answer
515 views

Is OCSP multi stapling supported by OpenSSL? [closed]

can anyone tell me for sure if OCSP multi stapling is supported by/implemented in the current version of OpenSSL? Those are the hints I found on the Web: OCSP stapling now is supported by OpenSSL, ...
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3answers
2k views

Is it possible to decrypt the 2nd byte of AES-256-CFB-8 ciphertext without decrypting the 1st byte?

I am stuck with AES-CFB decryption. Assume I encrypted plaintext helloworld (10 bytes) using AES-CFB. Now I want to decrypt the second byte ...
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1answer
146 views

Weird size of data transmitted in SSLv3

Note - I know SSLv3 is dangerous but that is why I am using it to do demo of POODLE attack using server and client written in python. So the question is I am using "ECDHE-RSA-AES128-SHA" cipher for ...
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1answer
1k views

Is openssl library safe threaded? [closed]

I'm encrypting in C++ with openssl library. Basically I'm using these functions: RAND_bytes(key, 32); AES_set_encrypt_key(...) AES_ctr128_encrypt(...) My purpose is to encrypt parallelly with ...
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2answers
3k views

Complete Set of Test-Vectors for ECDSA secp256k1

Although there are several implementations of ECDSA secp256k1 public available over the internet (the most popular being OpenSSL), it seems that there are no complete set of test-vectors available. ...
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2answers
2k views

What's wrong with RSA and OpenSSL?

We all know that signing a document is to encrypt its hash using signer's private key. https://commons.wikimedia.org/wiki/File:Digital_Signature_diagram.svg I've been searching the web for days, ...
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2answers
1k views

How Can I decrypt this VNC Authentication handshake?

I'm trying to analyze a mobile application and I believe it is is using DES. Here is a sample of the authentication handshake. ...
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1answer
2k views

How to generate sha 256 hash using https url

I want to generate sha256 hash of https url. ex: url "https://www.google.com/" I want sha hash of this url. I have tried extracting public key from ssl certificate and used following command. ...
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1answer
1k views

How is the PKCS #10 signature generated?

I'm generating certificate signing request in iOS, which does not provide proper ready-made API for CSR generation. Now the library I have used for CSR generation produces the different signature for ...
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1answer
240 views

Is there any use for PBKDF with empty password?

As the name suggests, password based key derivation functions are used for deriving a cryptographic key from, well, a password. Is there any use for PBKDFs with empty password? Does it give any ...
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1answer
773 views

How to create the right Blowfish padding? [closed]

I use the OpenSSL library for Blowfish encryption in ecb mode. The message are encrypted, but with the wrong padding, because of it I have a problems with decryption. What am I doing wrong? I checked ...
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1answer
1k views

'-in' is an invalid command. [closed]

While trying to convert private key into public key i get this error message. I used "openssl genrsa -des3 -out private.key 4096" to generate the private key and used "openssl -in private.key -...
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1answer
429 views

DES Weak Keys - Double Encryption

I know there are 4 known weak keys, their value and that double encryption using one of the weak keys should give back the plain text. I implemented this in OpenSSL. I have a plain text $m$ in a file ...
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2answers
117 views

Why don't parameters generated by dhparams conform to `(2^p) mod (p-1)/2 == 1`?

I've used openssl dhparams to generate 512-bit DH parameters for a test. The resulting file is: ...
2
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2answers
4k views

AES encryption without salt and IV

I need to encrypt blocks of 16KiB with AES256. I have only one requirement to satisfy - If one day a hacker gets the data without the keys, he will not be able to decipher the data. According to the ...
2
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1answer
9k views

Why is OpenSSL generated 256-bit AES key 64 characters in length?

This might be a noob question, but I couldn't find its answer anywhere online: why does an OpenSSL generated 256-bit AES key have 64 characters? The command I'm using to generate the key is: ...
3
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1answer
3k views

When a DER format RSA private key is extracted from an encrypted PEM file, is it still encrypted?

Let's pretend we create a passphrase protected PEM file using openssl: ...
3
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1answer
3k views

Extra attributes in a certificate signing request

When creating a certificate signing request, there is a part where openssl says "Please enter the following extra attributes to be sent with your certificate request". One of these is a challenge ...
6
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1answer
2k views

Nonce for AES GCM to prevent replay attacks

I am wanting to encrypt a message with a pre shared key that uses AES GCM from the OpenSSL library to do so. I generate my key for the AES crypto via hashing my pre shared key with a salt using the <...
2
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1answer
798 views

Why does 3DES need private key to decrypt?

I create two files, my.cer and my.pem ( include certificate and private key), I encrypt a file with my.cer, I use openssl smime -encrypt command. When decrypting data, it needs my.pem. I think 3DES ...
8
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2answers
7k views

What are KDF parameters in OpenSSL command-line utility for `enc`?

I refer to https://www.openssl.org/docs/manmaster/apps/enc.html and see that the only parameter for key derivation which I can set explicitly (not considering the obvious ...
2
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1answer
119 views

Insecure third party connection

My organization processes some PII data and shares it with an outbound connection (outflow only) that is a third party. The data transfer transactions occur without human intervention. That outbound ...
4
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2answers
7k views

Creating ECDH using OpenSSL

For academic reasons, I'm playing around with OpennSSL 1.0.2g. I tested RSA encryption/decryption. I created key exchange with DHKE. But I'm struggling to find a way, to create ECDH, using only ...
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1answer
468 views

Can TLS session resumption work after client dropped connection & reconnected to server?

I'm developing a sensor node and investigating TLS/OpenSSL. The network the node runs behind could drop and reconnect a lot. The node has limited data plan so data overhead is the key where TLS ...
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2answers
501 views

Is ssl_sign safe as it is using OPENSSL_PKCS1_PADDING

I've been hearing a lot of scare talk about PKCS1 padding attacks. Is PKCS1 v1.5 safe in signatures as it is practically transporting only message digest? I'm using it in one of my applications so i'...
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1answer
635 views

Does OpenSSL apply ASN1 encoding to the hash before signing using ECDSA?

I read on stack overflow that OpenSSL performs ASN1 encoding to the hash before signing it for, for ECDSA. In other words, OpenSSL performs the following steps when for an Elliptic curve key ...
6
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2answers
567 views

What may be causing conflicts in Whirlpool implementation versions?

I see by layman articles (e.g. at Wikipedia) that the Whirlpool hash function has seemingly three current versions. That is to say, they are referenced as ...