https://en.wikipedia.org/wiki/Comparison_of_cryptography_libraries [Comparison of available cryptography libraries]
scapy/MACSec AES-GCM support:
scapy uses python-cryptography v1.7+: [This is not “PyCrypto”.]
https://cryptography.io/en/latest/hazmat/primitives/aead/
https://github.com/pyca/cryptography [which binds to OpenSSL]
Did a quick check on supported GCM ciphers in OpenSSL:
$ openssl version
OpenSSL 1.0.2g 1 Mar 2016
$ openssl enc -help 2>&1 | grep gcm
-aes-128-gcm -aes-128-ofb -aes-128-xts
-aes-192-ecb -aes-192-gcm -aes-192-ofb
-aes-256-gcm -aes-256-ofb -aes-256-xts
It shows:
GCM-AES-128 (supported)
GCM-AES-256 (supported)
GCM-AES-XPN-128 (support not found yet)
GCM-AES-XPN-256 (support not found yet)
Microsemi (Microchip) MACsec (hardware acceleration) programming guide
http://ww1.microchip.com/downloads/en/DeviceDoc/VPPD-04004.pdf