Questions tagged [libsodium]

"The sodium crypto library". A cryptographic multi-language-library with support for many modern cryptographic primitives, that is a fork of the NaCl library. The library focuses on providing easy-to-use cryptographic primitives.

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Any gotchas when deriving a symmetric key from two seeds?

Consider a connection protocol where, after jumping through several other hoops, Alice and Bob know each others' public keys; and they now want to do a RSA-handshake-kind-of-thing to come up with a ...
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Can libsodium's X25519 encryption construction be generalized?

It is my understanding that libsodium's sealed_box is based on X25519, a Diffie-Hellman function: By combining the X25519 key agreement with a symmetric cipher and having a recipient derive the ...
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What happened to Poly1305AES? Is it obsolete?

I've been told that Poly1305AES is a great choice of MAC for constrained (embedded) environments. I'd checked out DJB's writing on it briefly, and have to say that I found its simplicity likeable, ...
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Should I use NaCl or libsodium for my application?

While looking for end-to-end encryption for my app users, I stumbled upon NaCl and libsodium. I am unsure from a security perspective which of these implementations I should use for my cross-platform ...
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What does “crypto_box” actually mean in libsodium and NaCl?

I cannot find what "crypto_box" actually means. In general, and in specific cases, what does "box" do? I know that libsodium is authenticated encryption, but GPG is not. "Box" makes me think the ...
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Proof possession of private key in libsodium

I would like to proof that I am in possession of private key sk for public key pk using ...
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NACL with public key encryption and authentication

As suggested in this answer i can use nacl for public key encryption with: ...
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is forward secrecy irrelevant for non-streaming applications?

I asked a question yesterday about the Keybase key model and got no answers, unfortunately. Let me rephrase the question to make it clearer: in the case, if 2 users just want to send each other low-...
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Verifying the ownership of curve25519 public keys

Let's say we have a group of users, authenticated by a server that providers the service, communicating on a secure channel (e.g. over HTTPS/TLS) and each user has a corresponding curve25519 key pair. ...
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Would XOR'ing two Argon2 keys add extra security?

When a user registers on the app, they need to provide a password they create and we provide them with a randomly generated passphrase (e.g. Apple Cat Ladder Fire). We then use Libsodium's ...
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Authenticated encryption using libsodium's crypto_box_curve25519xsalsa20poly1305

It seems that crypto_box_easy, generates a random nonce and appends it to the cipher text in libsodium. I understand using the same nonce with the same key can be ...
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Is it OK to just hash a symmetric key to derive an authentication key?

I'm using xsalsa20poly1305 for encryption in my program from libsodium. The recommended size for chunks is 4 kB. In that case, poly1305 will have authentication only for the the individual 4k chunks. ...
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Key clamping in curve25519 not evident in generated key's binary representation

I understand with curve25519 that the private key for secret.box is clamped... I understand that this clamping process to clear ...
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149 views

Key exchange and authentication using libhydrogen

I have been able to exchange session keys on two devices using Libhydrogen's Key exchange using the N variant method. I also want to authenticate both devices to have some protection against the Man ...
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Resetting a shared private key

I have a scenario with a user that needs to operate on common data from multiple devices but the link to the server is often offline. Unfortunately in the environment, I trust anything not directly in ...
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Which version of ChaCha is more secure?

Which version of ChaCha is more secure? XChaCha20-Poly1305-IETF ChaCha20-IETF-Poly1305 ChaCha20-Poly1305 I am looking for 256bit strength for large datasets. ...
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Using ECDH for encryption and decryption [duplicate]

I'm playing with cryptography and its use with typescript on one side and PHP on the other side. Now I'm looking for routines that can encrypt and decrypt with ecdh's private and shared keys. Any ...
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specific scenario question relating to using NACL crypto_box in a protocol

Scenario 1: SenderA sends message1 to ReceiverB message1 is encrypted using NACL crypto_box using SenderA secret key and ReceiverB public key. we understand that the NACL crypto_box authenticator ...
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332 views

Using public-key signature instead of having API key

I am designing an application that will need an API key. At first I believed that generating a long, random token would be secure enough (say 32 chars string that includes 0-9, a-z and A-Z), and then ...
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Representations of secret keys on Curve25519

https://tools.ietf.org/html/draft-josefsson-tls-curve25519-06#appendix-A.2 gives the following as a secret key / public key combo: ...
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How can I follow the validation and verification recommendations of the NaCl (sodium) secretbox library?

I was advised to use crypto_secretbox_xsalsa20poly1305 due to its simplicity and because it's safe against timing attacks. I'm reading the secretbox tutorial, and ...
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Does libsodium sealed box leak key ids?

I am using python and libnacl, which is a libsodium wrapper, to develop an application where users can deposit encrypted data. Alice uses ...
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libsodium vs gnupg curve25519 compatibility

I am trying to create deterministic GPG keys based on cryptosteel. I have implemented a library for (de)serializing PGP packets and am now trying to use keys generated in libsodium for import in GPG. ...
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Verion of crypto_box() which doesn't allow the sender to decrypt previously sent messages

Libsodium's crypto_box() family of functions allow the sender to send messages using its public/private keypair knowing the receiver's public key, and allow the ...
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Using a LibSodium CryptoBox KeyPair with `crypto_sign`

More of a theoretical question... Taking a system where Lib Sodium has been used for asymmetric encryption, where a "crypto_box_keypair" has been generated, and the public key has been distributed to ...
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On Linux, seeding /dev/urandom does not unblock /dev/random, causing libsodium to hang? [closed]

Edit for clarity: Does the "standard" test for initialization of the Linux non-blocking entropy pool, by attempting to read 1 byte from /dev/random, ignore seeding of /dev/urandom from file at boot, ...
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libsodium stream encryption [closed]

I am new to cryptography, I have used OpenSSL and its aes-256-cfb cipher before to do stream encryption, which works great. Now I am going to try ...
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Verification of HMAC in libsodium

libsodium verifies that the HMAC is correct with the following code: return crypto_verify_32(h, correct) | (-(h == correct)) | sodium_memcmp(correct, h, 32); ...
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Is it possible to derive the recipient's public key from libsodium's crypto_box?

Libsodium has "crypto_box_seal" which according to the documentation is used to "anonymously send messages to a recipient given its public key.", which hides the sender. But Is it possible for Eve to ...
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What is special about an entropy count (RNDGETENTCNT) of 160 for libsodium initialization?

(Moved from StackOverflow) In the Usage documentation for libsodium, before calling the initialization function sodium_init, they suggest you check the entropy ...
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What is the difference between a sealed box and a normal box in libsodium?

I'm trying to learn libsodium to better my crypto knowledge. One nagging question I have is what is the difference between libsodium's sealed box and their normal box? Not in terms of technicalities ...
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I have this list of LibSodium primitives, which should I pick so that the implementations tend to be interoperable?

When I integrate lib sodium, into a c# project, and try to consume, encryption and decryption in a particular way, it works, but the confusion is about, which method to use while encryption or ...
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P2P Website/Database Encryption Process

Sorry if this doesn't fit the guidelines, but I believe it is a conceptual issue that is not opinion-based and can be reasonably answered in a single authoritative answer (I'm also struggling to find ...
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Why are 48 bytes appended to Libsodium encrypted messages if nonce is 24 bits?

When encrypting a string through the Libsodium secret box feature, the ciphertext is 48 bytes longer than the plain text message ... I am wondering why this is ... since the nonce is only 24 bytes.
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Schnorr NIZK over Ed25519

I am trying to implement the following Schnorr non-interactive zero-knowledge protocol: https://tools.ietf.org/html/rfc8235#page-7 I'm using the libsodium 1.0.16 and GNU MP libraries. I just can't ...
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libsodium x25519 and Ed25519 small order check

Studying libsodium implementation of x25519 and Ed25519 I saw that it performs an small order check comparing given inputs with a hard coded blacklist of values. Is this list exhaustive or it is a ...
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Encrypt or decrypt using the private key, and decrypt using the public key?

I am currently trying to figure out if my following scheme is implementable in ECC or whether I can use existing implementation. At first I was going with libsodium but it seems that it really doesn't ...
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Is libsodium's `box` construct secure without additional manual padding of the plaintext before encryption?

I have read the following questions and answers: How safe are Libsodium Crypto Boxes? What can be learned from the ciphertext of LibSodium's crypto_box_detached()? However, neither of these ...
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How to use Libsodium encryption (in PHP) in the most secure possible way?

In a PHP project in which fool-proof encryption is fundamental, I'm using the Libsodium library. Hope you guys can shine some light on the following questions. For all of the following functions, it ...
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How safe are Libsodium Crypto Boxes?

I am currently working on a huge PHP project and we are seriously considering to use the Libsodium PHP library in it. My question is related to the "sodium crypto box" functionality. We would use ...
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Libsodium installation issue: Invalid library (maybe not a PHP library) 'sodium.so' in Unknown on line 0 … [closed]

I've been struggling since days to install libsodium on my Debian9/php7.0(with fpm) server ... When I follow the steps outlined on https://paragonie.com/book/pecl-libsodium/read/00-intro.md#installing-...
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Does it matter whether the KDF salt is integrity protected?

I am writing a simple application, mainly as a fun challenge, but also to hopefully someday use as my password manager. I'm using pynacl's SecretBox, which ...
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Is the following crypto compatible so that I can use the same keys for both products (Wireguard & Libsodium)?

I am wondering if it is possible to use the public/private keys of two WireGuard peers also in another communication channel using libsodium? According to the WireGuard Protocol documentation and the ...
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How to find the secret key and nonce from two messages encrypted using the same nonce?

As far as I understand, nonces must not be reused because their reuse allows public key encryption to be broken. If I use NaCl's crypto_box http://nacl.cr.yp.to/...
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Why NaCL does not provide anonymous public key cryptography?

At the same time Sodium provides API for anonymous encryption without using ephemeral keys. Is it a bad practice to just use other user public key to encrypt a message?
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How do I properly calculate an inverse element for curve25519 when implementing Sphinx password store protocol?

There's a new password store mechanism, called Sphinx http://webee.technion.ac.il/~hugo/sphinx.pdf which is very nice and protects from device or user compromise. I haven't found any implementations ...
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Nonce reuse resistance

I read this article and I think the approach outlined there is very interesting for one of our use case. We use ChaCha20 Poly1305 (via Sodium ...
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Does using crypto_stream_xor allow listeners to forge crypto_secretbox messages?

I understand that NaCl's crypto_stream and crypto_stream_xor don't do any authentication, like ...
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Why/how is libsodium/nacl's cryptobox repudiable?

https://nacl.cr.yp.to/box.html see "security model". As far as I can see, Alice encrypts a message using her private key, Bob's public key and a nonce. Bob decrypts the message using Alice's public ...
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Why do two Argon hashes with the same password differ?

Can someone explain to me what the ArgonHashString function in libsodium returns (i'm using the .net port). For example i called it twice with the same string: ...