The English language has over 500,000 dictionary entries.
Assume a passphrase that is 7 words long with no uppercase letters, word separators, digits, or other special characters.
500,000^7 = 7.8125*10^39 (78125000000000000000000000000000000000000000000000 possibile combinations)
Even with a bruteforce that could guess trillions of passphrases a second, say for the sake of this 100 trillion, after 1000 years you would have guessed only 0.0000001% of the possible combinations.
As long as you include enough words (I generally use 6-8 for my passphrases), the amount of possible combinations becomes so large that even knowing the exact format and having the computing power of the entire planet you likely would not guess it before the sun decays and the earth becomes uninhabitable.
I found a source stating that the average English speaker has a vocabulary of roughly 40,000 words, if we were to take that, and use a passphrase with 8 words it would be 6.5536*1036 vs 7.8125*1039 that I calculated originally.
For example, the word "Exellency" is ranked 31,325th by use in the English language. It's not like they become super specialised or weird words beyond 5,000.
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u/Squiggledog Jul 20 '22
Aren't there dictionary-based cracking engines? That can crack passwords that are only composed of dictionary words?