Answer: 26! or [tex]\approx 4.03\times10^{26}[/tex]
Step-by-step explanation:
Given : The Caesar Cipher has 25 different shifts to try.
Since the total a letters in the English Alphabet = 26
Then, the number of possibilities in a random substitution cipher = [tex]26![/tex]
[tex]=26\times25\times24\times23\times...\times3\times2\times1\\\\=4.03\times10^{26}[/tex]
Hence, there are 26! ( or [tex]\approx 4.03\times10^{26}[/tex]) possibilities to try in a random substitution cipher .