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

I have been given the following public RSA key: ...
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2answers
884 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 ...
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Why does openssl derive IVs from a password?

From https://wiki.openssl.org/index.php/Manual:Enc(1): When a password is being specified using one of the other options, the IV is generated from this password. Why does OpenSSL do this? My ...
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1answer
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Can we use higher strength SHA along with lower strength RSA key in SSL?

I have noticed when the RSA public key is 2048 bit, SHA-256 bit used for signatures. When the key is 3072 bit, SHA-384 bit used. When the key is 4096 bit, SHA-512 bit used. I have tried the ...
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3answers
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Is there a complete list of Signature Algorithm names?

I need to analyze the output of rbsec's sslscan which reports a server's SSL/TLS configuration as reported by OpenSSL. I'm interested in the Certificate's Signature Algorithm in particular, and I was ...
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1answer
543 views

Is the openssl implementation of ECDH missing something?

From the OpenSSL Wiki: Also note that the derived shared secret is not suitable for use directly as a shared key. Typically the shared secret is passed through some hash function first in order to ...
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1answer
697 views

TLS 1.3: the key_share in a ClientHello after a HelloRetryRequest

In TLS 1.3 draft-21, if there is a ClientHello with a key_share, say, $(G_1, g^x)$, the server can send a ...
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0answers
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Estonian e-voting, vote verification system

I believe I do understand the basics of how the Estonian e-voting system works, but I'm stuck at their vote verification system. In order to get the vote verified, a client needs to encrypt all of the ...
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2answers
3k views

What is the relation between x y and r s in an ECDSA signature?

I'm writing functions in C using OpenSSL and the EVP interface to interact with Intel SGX. One of those functions calculates an ECDSA (with SHA256) signature over some data. The output of the ECDSA ...
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ChaCha20-Poly1305 test vectors

I was trying to use OpenSSL 1.1 (via Ruby) to validate the ChaCha20-Poly1305 test vector from this IETF draft: https://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04#section-7 The relevant ...
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1answer
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Encrypted cerficiate signature for server certificate and intermediate certificate in packet capture

If we view the certificate chain using Firefox, we can see the certificate signature of "server certificate" and its "intermediate-CA" right after the "certificate signature algorithm" in the ...
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1answer
544 views

How does the TLS cipher suite DHE-RSA-AES128-CCM8 work without hashing algorithm

I came across cipher suites without hashing algorithm, when inspecting the mbedTLS (previously Polar SSL) TLS cipher suite list. For example: TLS-DHE-RSA-WITH-AES-128-CCM-8 (OpenSSL: DHE-RSA-AES128-...
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2answers
2k views

Security of CCM in TLS, in comparison to GCM, SHA or SHA2 for the digest

I've been looking into TLS cipher suites of OpenSSL and mbedTLS (previously called PolarSSL) and noticed that mbedTLS supports the CCM mode of operation (See list here), whereas OpenSSL does not. If I ...
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1answer
733 views

Default mode of operation in TLS cipher suites

I've been trying to evaluate the security of a list of cipher suites and I've come across cipher suites, not explicitly featuring a mode of operation. Form this list (openvpn --show-tls), one of such ...
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1answer
3k views

DSS security in comparison to ECDSA or RSA

OpenVPN allows the users to choose the TLS cipher suite, depending on the deployed SSL/TLS library. With OpenSSL 1.0.2g and OpenVPN 2.3.11 this is a rather long list (Full list). Amongst the many ...
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1answer
2k views

Node.js/OpenSSL crypto library equivalent of a Rijndael implementation

I have a Rijndael function that I've implemented as a JavaScript port of a C reference implementation in a technical specification for the MILENAGE algorithm (ETSI TS 135 206 V14.0.0 (2017-04)). My ...
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2answers
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How much entropy do you need for a secure certificate generation?

So in OpenSSL you have the -engine tag for inputting your own entropy as a source for generating whatever. So if you wanted to generate a 2048-bit RSA certificate ...
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How different is SHA512/224 when compared with SHA512?

From http://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.180-4.pdf Nist document what i understood is while implementing SHA512 and SHA512/224 the two differences are the Initial hash value and the final ...
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Algorithms to securely derive symmetric keys

I need to derive symmetric keys between two communication endpoints on an embedded device with 800MHz ARM core. What algorithms are available to have this secure key derivation mechanism? I know ...
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1answer
55 views

Are applications aware of data records received before and after tls rehandshake?

It seems that a tls endpoint can pump more data records even when it has received a re-handshake request from peer. Also in dtls, new data records would get accepted even while rehandshake is in ...
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1answer
3k views

How do I use AES-256-CTR correctly?

Is there any specific method to use AES-256-CTR correctly? I heard a Playstation 3 security vulnerability was exploited due to a CTR error. I would like to avoid this. How Do I Use AES-256-CTR ...
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Does the size of a file influence the randomness if used as random input?

(I am a cypto amatuer ) So in Openssl there is the "-rand" option for taking a file containing randomness for the RNG . So I thought taking a pretty big file would make it more secure . So if you ...
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1answer
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How to change the policy value of a CA identity in apple keychain?

According to this guide, I made an intermediate CA, and successfully used it to sign app in Windows. However, after converted it into a Apple keychain (by this guide), this CA become having an "iChat" ...
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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
616 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
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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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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
660 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
899 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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3answers
7k 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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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
469 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
8k views

Encryption, Decryption using OpenSSL

How to use OpenSSL in windows for encryption and decryption ?
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3answers
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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
481 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: ...
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1answer
356 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? ...
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1answer
674 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
279 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 ...
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1answer
296 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
281 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
7k 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
342 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
5k 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 ...
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1answer
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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
192 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
576 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
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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
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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
2k 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 ...