In Libgcrypt before 1.7.7, an attacker who learns the EdDSA session key (from side-channel observation during the signing process) can easily recover the long-term secret key. 1.7.7 makes a cipher/ecc-eddsa.c change to store this session key in secure memory, to ensure that constant-time point operations are used in the MPI library.
En Libgcrypt, anterior a versión 1.7.7, un atacante que aprende la clave de sesión EdDSA (de la observación del canal lateral durante el proceso de firma) puede fácilmente recuperar la clave secreta a largo plazo . 1.7.7 haciendo un cambio del archivo cipher/ecc-eddsa.c para almacenar esta clave de sesión en memoria segura, y así garantizar que operaciones puntuales de tiempo constante sean usadas en la biblioteca MPI.
Daniel J. Bernstein, Joachim Breitner, Daniel Genkin, Leon Groot Bruinderink, Nadia Heninger, Tanja Lange, Christine van Vredendaal, and Yuval Yarom discovered that Libgcrypt was susceptible to an attack via side channels. A local attacker could use this attack to recover RSA private keys. It was discovered that Libgcrypt was susceptible to an attack via side channels. A local attacker could use this attack to possibly recover EdDSA private keys. This issue only applied to Ubuntu 16.04 LTS, Ubuntu 16.10 and Ubuntu 17.04. Various other issues were also addressed.
