Add new key fingerprint.
(cherry picked from commit 3143a332e8f2f5ca1a6f0262a1a1a66103f2adf7)
Clarify CMS_decrypt behaviour.
(cherry picked from commit 5f8e9a477a18551052f2019c1f374061acbaa5e6)
Extension checking fixes.

When looking for an extension we need to set the last found
position to -1 to properly search all extensions.

PR#3309.
(cherry picked from commit 300b9f0b704048f60776881f1d378c74d9c32fbd)