Encrypted virus

Definition
An  encrypted virus

"has two parts: a small decryptor and the encrypted virus body. When the virus is executed, the decryptor will execute first and decrypt the virus body. Then the virus body can execute, replicating or becoming resident. The virus body will include an encryptor to apply during replication. A variably encrypted virus will use different encryption keys or encryption algorithms. Encrypted viruses are more difficult to disassemble and study since the researcher must decrypt the code."