Problem $2$: $[25$ points$]$ Please encrypt the message "Computer Science" by using Additive cipher $2$ with key $=18$; Ignore the space between the words. Please show all details and ignore the space between words.

$[1]$ The values of the corresponding plain text $[10$ points$].$

$[2]$ The value of the corresponding cipher text $[10$ points$].$

$[3]$ The final result of the corresponding cipher text $[5$ points$].$

Problem $3[25$ Points$]$: Encrypt the message "your grade" using the Vigenere cipher with key: $"$At TSU". Ignore the space between the words. Please include the following results:

$[1]$ The values of the corresponding plain text $[7-$points$].$

$[2]$ The value of corresponding key stream $[7$ points$].$

$[3]$ The value of the corresponding cipher text $[7$ points$].$

$[4]$ The final result of the corresponding cipher text $[4$ points$].$