| Abbreviation | Definition |
|---|---|
| MDC | Modification Detection Code |
| ME | Malicious Environment |
| ME | Message Encryption |
| MEA | Message Encryption Algorithm |
| MEK | Message Encryption Key |
| MEL | MIME (Multipurpose Internet Mail Extensions) Encoding Library |
| MESH | Multimedia Embedded Security Hub |
| MFA | Multi Factor Authentication |
| MGE | Multi Gauntlet Emulator |
| MI | Message Invader |
| MIC | Message Integrity Code |
| MIDAS | Monitoring Intrusion Detection and Administration Server |
| MISK | McGruff Internet Safety Kit |
| MITM | Man In The Middle |
| MITMA | Man-In-The-Middle Attack |
| MK | Modular Key |
| MKB | Media Key Block |
| MKM | Modular Key Management |
| MKMP | Modular Key Management Protocol |
| MLE | Multiple Line Encryption |