/ 
Crypt-Sodium-XS-0.000021
/ Crypt::Sodium::XS::OO::kx
Security Advisories (3)
CVE-2025-15444 (2026-01-06)

Crypt::Sodium::XS module versions prior to 0.000042, for Perl, include a vulnerable version of libsodium libsodium <= 1.0.20 or a version of libsodium released before December 30, 2025 contains a vulnerability documented as CVE-2025-69277  https://www.cve.org/CVERecord?id=CVE-2025-69277 . The libsodium vulnerability states: In atypical use cases involving certain custom cryptography or untrusted data to crypto_core_ed25519_is_valid_point, mishandles checks for whether an elliptic curve point is valid because it sometimes allows points that aren't in the main cryptographic group. 0.000042 includes a version of libsodium updated to 1.0.20-stable, released January 3, 2026, which includes a fix for the vulnerability.

CVE-2026-30910 (2026-03-08)

Crypt::Sodium::XS versions through 0.001000 for Perl has potential integer overflows. Combined aead encryption, combined signature creation, and bin2hex functions do not check that output size will be less than SIZE_MAX, which could lead to integer wraparound causing an undersized output buffer. This can cause a crash in bin2hex and encryption algorithms other than aes256gcm. For aes256gcm encryption and signatures, an undersized buffer could lead to buffer overflow. Encountering this issue is unlikely as the message length would need to be very large. For bin2hex the input size would have to be > SIZE_MAX / 2 For aegis encryption the input size would need to be > SIZE_MAX - 32U For other encryption the input size would need to be > SIZE_MAX - 16U For signatures the input size would need to be > SIZE_MAX - 64U

CVE-2025-69277 (2025-12-31)

libsodium before ad3004e, in atypical use cases involving certain custom cryptography or untrusted data to crypto_core_ed25519_is_valid_point, mishandles checks for whether an elliptic curve point is valid because it sometimes allows points that aren't in the main cryptographic group.

NAME

Crypt::Sodium::XS::OO::kx - Asymmetric (public/secret key) derivation from client/server asymmetric key pairs

SYNOPSIS

use Crypt::Sodium::XS;
my $kx = Crypt::Sodium::XS->kx;

# client
my ($client_pk, $client_sk) = $kx->keypair;
my ($server_pk, $server_sk) = $kx->keypair;

# client must have server's public key
# shared keys for server->client (client_rx) and client->server (client_tx)
my ($client_rx, $client_tx)
  = $kx->client_session_keys($client_pk, $client_sk, $server_pk);

# server must have client's public key
# shared keys for client->server (server_rx) and server->client (server_tx)
my ($server_rx, $server_tx)
  = $kx->client_session_keys($server_pk, $server_sk, $client_pk);

DESCRIPTION

Using Crypt::Sodium::XS::kx, two parties can securely compute a set of shared keys using their peer's public key and their own secret key.

CONSTRUCTOR

new

my $kx = Crypt::Sodium::XS::OO::kx->new;
my $kx = Crypt::Sodium::XS::OO::kx->new(primitive => 'x25519blake2b');
my $kx = Crypt::Sodium::XS->kx;

Returns a new kx object for the given primitive. If not given, the default primitive is default.

METHODS

PRIMITIVE

my $kx = Crypt::Sodium::XS::OO::kx->new;
my $default_primitive = $kx->PRIMITIVE;

PUBLICKEYBYTES

my $public_key_length = $kx->PUBLICKEYBYTES;

SECRETKEYBYTES

my $secret_key_length = $kx->SECRETKEYBYTES;

SEEDBYTES

my $seed_length = $kx->SEEDKEYBYTES;

SESSIONKEYBYTES

my $session_key_length = $kx->SESSIONKEYBYTES;

primitives

my @primitives = $kx->primitives;

Returns a list of all supported primitive names (including 'default').

keypair

my ($public_key, $secret_key) = $kx->keypair;
my ($public_key, $secret_key) = $kx->keypair($seed);

$seed is optional. If provided, it must be "kx_SEEDBYTES" in length. Using the same seed will generate the same key pair, so it must be kept confidential. If omitted, a key pair is randomly generated.

client_session_keys

my ($client_rx, $client_tx)
  = $kx->client_session_keys($client_pk, $client_sk, $server_pk);

server_session_keys

my ($server_rx, $server_tx)
  = $kx->client_session_keys($server_pk, $server_sk, $client_pk);

SEE ALSO

Crypt::Sodium::XS
Crypt::Sodium::XS::kx
https://doc.libsodium.org/key_exchange

FEEDBACK

For reporting bugs, giving feedback, submitting patches, etc. please use the following:

  • IRC channel #sodium on irc.perl.org.

  • Email the author directly.

AUTHOR

Brad Barden <perlmodules@5c30.org>

COPYRIGHT & LICENSE

Copyright (c) 2022 Brad Barden. All rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.