Add match timetable

See cathugger/mkp224o#27 (comment)

README.md

@@ -53,10 +53,23 @@ PASS
 ok      github.com/AlexanderYastrebov/wireguard-vanity-key      21.154s
 ```
 
+Time to get n-symbol prefix at rate 18'000'000 keys per second with probability of:
+```
+n                  50%                  95%                  99%
+4              0:00:01              0:00:03              0:00:04
+5              0:00:41              0:02:59              0:04:35
+6              0:44:06              3:10:37              4:53:01
+7      1 day, 23:02:41     8 days, 11:19:25     13 days, 0:33:28
+8   125 days, 10:51:28    542 days, 4:42:40   833 days, 11:42:23
+```
+I.e. you may expect a match for a 5 character prefix after
+41 seconds 50% of the time and after 4-5 minutes to be 99% sure.
+
 ## Similar projects
 
 * [wireguard-vanity-address](https://github.com/warner/wireguard-vanity-address)
 * [wireguard-vanity-keygen](https://github.com/axllent/wireguard-vanity-keygen)
 * [Wireguard-Vanity-Key-Searcher](https://github.com/volleybus/Wireguard-Vanity-Key-Searcher)
 * [wgmine](https://github.com/thatsed/wgmine)
 * [Vanity](https://github.com/samuel-lucas6/Vanity)
+* [mkp224o](https://github.com/cathugger/mkp224o)

matchtime.py

@@ -0,0 +1,33 @@
+#!/usr/bin/env python3
+'''
+Prints the time table it would take for the number of trials t at rate r
+to get at least 1 match with n characters of base b and a probability p with the formula
+
+    t = log(1-p)/log(1-1/b^n)
+
+See https://github.com/cathugger/mkp224o/issues/27#issuecomment-568291087
+'''
+import math
+import datetime
+
+R = 18_000_000
+P = [50, 95, 99]
+N = [4, 5, 6, 7, 8]
+B = 64
+
+def t(p, n):
+    return math.log(1 - p/100) / math.log(1 - 1/B**n)
+
+print('Time to get n-symbol match at rate {R} trials per second with probability of:')
+print('n', end='')
+for p in P:
+    print(f' {p:19d}%', end='')
+print()
+
+for n in N:
+    print(n, end='')
+    for p in P:
+        v = t(p, n) / R
+        s = str(datetime.timedelta(seconds=round(v)))
+        print(f' {s:>20}', end='')
+    print()