Debian DSA-4233-1 Critical: Bouncy Castle RSA Key Test Risk

It was discovered that the low-level interface to the RSA key pair
generator of Bouncy Castle (a Java implementation of cryptographic
algorithms) could perform less Miller-Rabin primality tests than
expected.

For the stable distribution (stretch), this problem has been fixed in
version 1.56-1+deb9u2.

We recommend that you upgrade your bouncycastle packages.

For the detailed security status of bouncycastle please refer to
its security tracker page at:
https://security-tracker.debian.org/tracker/source-package/bouncycastle

Further information about Debian Security Advisories, how to apply
these updates to your system and frequently asked questions can be
found at: https://www.debian.org/security/