There is no absolutely no need for your password to be this long. Even just twenty characters is within spitting distance of 2^128.
No it's not. User-chosen data is rarely random, so it's safe to say that Santosh83's password is not random. This article claims English has 1.46 bits of entropy per character[1]. If Santosh83's password is regular English, then it would have ~105 bits of entropy.
>Even just twenty characters is within spitting distance of 2^128
Someone[2] sent bitcoins to a brainwallet secured only by the phrase "it was the best of times" (24 characters). The bitcoins were stolen in 4 seconds. 20 characters is not enough. You need to do actual entropy analysis. And don't use quotes from anywhere. Crackers crawl the internet and build databases of all the quotes they find online. This tends to include book quotes, movie quotes, etc.
[1] https://www.gwern.net/docs/statistics/1996-teahan.pdf
[2] https://www.reddit.com/r/Bitcoin/comments/1ndsxi/a_test_of_b...
Sure, perhaps it's just a phrase or something, but once you start calling part of a post a lie where do you stop? I'd rather not get into such a mess.
Yes, "from the full set" likely means that it's higher than 1.46 bits/character. But it doesn't mean it's much more.
The average password isn’t random. But GP was not describing anything remotely close to an average password in the first place.
Turns out (according to GP) it isn’t random. But I stand by my point that it was a reasonable assumption given the available data.
KeePass reports it as having 222 bits entropy although I don't know how accurate an analysis that is.