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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Does the libsodium sealedbox provide forward secrecy?

I am using sodiumoxide, a Rust binding to libsodium that provides a function named sealedbox that requires the receiver's public key. However, they also mention that the message is encrypted with an ...
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How feasible is it to guess the private key of libsodium by taking into account generation time?

So suppose you are doing this locally (so no network noise), and know the exact specifics of your processor too. Is it feasible to figure out the private key (while having access to the public-key) ...
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Disparity between PyNaCl docs and libsodium docs

So if we look here, it shows that libsodium uses three 3 different algorithms for this, which sounds weird to me, cause nothing indicates that anything besides Curve25519 is used in those specific ...
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Convert sr25519 key pair to Curve25519 key pair

I'm trying to implement public key encryption that support key pairs generated by different libraries: Curve25519 - libsodium cryptoBoxKeypair() Ed25519 - Google ...
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Implement deterministic authenticated encryption using libsodium

Note: this is my first question on stack exchange, let me know if you miss some details to answer and I will edit the question accordingly Context I'm willing to create a git encryption tool (...
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Generate secp256k1 ECC key pair with libsodium

I'm new to crypto and I want to generate a key pair, in C, which would be the equivalent of openssl ecparam -name secp256k1 -genkey -out ec-priv.pem. I love ...
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Is CMS for data still relevant

I have an application where I need to store small to moderate amounts of data in a symmetrically encrypted form. For various reasons, CMS with an AuthEnvelopedData seems to tick all the requirements. ...
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One way shared key encryption with NaCl - is it safe to generate a throwaway keypair for the encrypting party

So, I need users to be able to pass me information that no one else can read, so I've generated a secret key. Using NaCl I create a key pair from that secret key and I share the public key of the key ...
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How do I convert an ed25519 scalar into x25519 for encryption?

In a system I'm working with, we're using Schnorr signatures with scalars generated with libsodium's crypto_core_ed25519_scalar_random. My goal is to use the ...
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Using crypto_sign then crypto_box_seal for anonymous messages

If you have a message M and you want the sender (alice) to be anonymous to everyone but the recipient (bob), is it ok to do? ...
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How to find out the block size of Xchacha20 in Libsodium?

I heard that Xchacha20 works like a block cipher so that even if it wants to encrypt one byte, it will do the work of at least one block. So technically it works similar to a block cipher in counter ...
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Using a nonce as a salt for key derivation

I'm currently playing a bit with PyNaCl (python binding to libsodium) and I want to use the secretbox for symmetric encryption between two parties, which means they both must know the (in my case ...
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Negotiating a session key, when only one public-key is exchanged via QR Code

Question I want to create a secure channel between a server and a client. It is only important that the client can verify the identity of the server, not the other way around. In my special case, an ...
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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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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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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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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 ...