Individual assigment files can be found in the location:

http://echidna.maths.usyd.edu.au/~kohel/tch/Crypto/Assignments/01/LastFirstMiddle.pdf

The raw data ciphertext files for this assigment are:

http://echidna.maths.usyd.edu.au/~kohel/tch/Crypto/Assignments/01/Ciphertext/LastFirstMiddle.i.txt

Replace (Last,First,Middle) with appropriate names, and i with the integers (1,2,3,4,5).

FAQ/NOTES:

1. After reading a ciphertext ct into SAGE, 

sage: ct = open("Ciphertext/LastFirstMiddle.1.txt").read()

you will need to apply 

sage: ct = strip_encoding(ct) 

or encoding as an alphabetic string:

sage: S = AlphabeticStrings()
sage: ct = S.encoding(ct)

in order to remove the end-of-line characters ('\n').