Ubuntu Security Notice 2913-3 – USN-2913-1 removed 1024-bit RSA CA certificates from the ca-certificates package. This update adds support for alternate certificate chains to the OpenSSL package to properly handle the removal. The ca-certificates package contained outdated CA certificates. This update refreshes the included certificates to those contained in the 20160104 package, including the removal of the SPI CA and CA certificates with 1024-bit RSA keys. Various other issues were also addressed.