Meaning of CER in English
Canonical Encoding Rules
another specialized form of BER that is similar to DER, but is meant for use with messages so huge that it is easiest to start encoding them before their entire value is fully available. CER is rarely used, as the industry has locked onto DER as the preferred means of encoding values for use in secure exchanges.
Acronyms Misc English vocab. Словарь сокращений и аббревиатур английского языка. 2012