Does it mean creating Vanity Legacy and Nested Segwit address is 14.26 times harder than Vanity Native Segwit address? And why?
It has something to do with number of possible combinations.
Since Legacy and Nested-SegWit both are encoded with BASE58 which has 58 possible characters, the total number of combinations will be bigger than bech32 (
BASE32).
In your test, you've used 5 character prefix in Legacy and 6 characters in Nested-SegWit,
if you've used the same number of characters, the latter will be less difficult with 264104224 difficulty due to the limited range of the first character in the prefix.
When it comes with speed, notice that Nested-SegWit keys-per-second is a lot slower than legacy or native SegWit?
That's because it has to go through HASH160 "
SHA256(RIPEMD160)" twice which is quite slow to compute; the other two only use it once.
Then bech32 has the fastest speed (
a little faster than legacy) because bech32's checksum (
bip-0173) doesn't use double SHA256 which makes it faster to compute.