All of the remaining questions involve the following toy encryption scheme. It encrypts plaintexts that consist of only

[answerhappygod]

All of the remaining questions involve the following toyencryption scheme. It encrypts plaintexts that consist of onlyuppercase letters and the underscore character (27 characterstotal):
ABCDEFGHIJKLMNOPQRSTUVWXYZ_
Note that the underscore character is part of the alphabetand will also be encrypted. A key in this scheme consists of 4digits, each from 0 to 9. Each digit tells how much toshift one character, that is, change it to the characterthat many positions later in the alphabet. If the shift goes past'_', then we wrap around to the beginning.
The key is applied separately to each group of 4 letters in themessage. For example, if the message HI_SALLY is encrypted with thekey 2417, the H would be shifted by 2, the I by 4, the underscoreby 1, and the S by 7. Then we would start over with the first digitof the key, shifting A by 2, L by 4, and so on. So the ciphertextwould be: JMAZCPLE.