I don't question your memory, that is not my point. How long do you think it takes to crack a password that consists of digits of Pi or anything derived from it? And it's not about Pi either, it's just that you can't beat a computer in that regard.

For me, playing around with hashcat, was an eye opening experience and I truly believe in the Schneier quote from above.

Create a 10 word diceware passphrase, using the EFF's list. Try to memorize it, it shouldn't take long. Hash it with whatever hash you like. Even MD5. Try to crack it with Haschat. Spend as much time and/or money as you like on the project. It's got over 128 bits of entropy, you won't succeed before the Sun becomes a red giant and incinerates the Earth.

I agree with Schneier's quote, but you're also forgetting about password hashing. If it takes 10 seconds to derive the key (assuming the use of a strong hash function), anything with a good enough amount of entropy (60-90 bits) should be fine.

When an attacker acquires a leaked database, they're not cracking high entropic passwords.

Yes, what speaks for dheera's method is the use of a strong KDF and especially (a point that I missed initially) that they use a truly random master password.

The standard password manager is slightly better because the password database works like a 2nd factor.

Also, a character has at most 8 bits of entropy, not 64. If you use base 64 its only 6 bits of entropy. 16 x 6 = 96 bits is still more than enough though.

A downside if everyone used this scheme would be parallelized attacks on reversing the hash for the key. If you find a key that, with this scheme, creates a password for your service, you found the corresponding secret key. This then compromises all of that users passwords.

Sorry early morning here, I actually fixed that before I saw your comment -- more like 6 bits per character. In any case more than good enough.

I actually am not a fan of 2nd-factor authentication (e.g. phone). If you lose the physical thing or it gets leaked to a stranger, gunman who mugs you, leaked by security holes in the thing's own embedded OS, it's no longer helping your security. I'd rather authentication depend on only what's in my mind and body and nothing external. Also, I lose stuff and forget stuff pretty easily, so I often just avoid carrying anything.

Which technique did you use? I made it to around 150 using the memory palace technique from the excellent book Moonwalking with Einstein.

I'm not sure what the various methods are called or what they are -- never really researched it. I just memorized about 10 digits every day over the course of a summer. Every day I practiced typing out the entire thing a few times as well as practiced the most-recent 100-block several more times.

That's very impressive!

And I thought my memorizing 100 digits was an achievement