3 ms·
Compare possible brute force combinations:
(26+10)^5 vs. 10^12
Compare possible brute force combinations:
(26+10)^5 vs. 10^12
That would be 10e12 vs 60.466.176. Pretty easy from the security pov.
Also if an alphanumeric string should be entered / remembered by humans make sure to strip I, l, etc.
For case-sensitive alphanumeric: (26+26+10)^5
Which is still far lower than 12 digits.