Not sure which platform (iOS/Android) you're using or which version of Yoroi wallet. And, I'm a bit confused about the two options. In my Yoroi application (Android, Yoroi v4.0.2, Commit ea5c1120) I see the option to access my wallets (saved) or, at the bottom, ADD WALLET (SHELLY-ERA) ADD WALLET (BYRON-ERA DEPRECATED) So, if you don't see your wallet(s) ...


Following the BIP39 standard, 15 word seeds are proving about 160 bits (20 bytes) of entropy, where 24 word seeds are providing around 254 bits (32 bytes) of entropy. As long as you do everything to protect your word seed, 160 bits of entropy is plenty. In the past, people used 24 words to split it into two parts, but today they are better ways to split your ...


According to CIP3: Wallet key generation, Cardano is using seed words from BIP39, therefore you can use words included in BIP39 only.


BIP39 wordlist contains 2048 words. If you use a 24-word phrase, you'll get 2048²⁴ possible combinations, or 2^264. This is an insultingly huge number. For hackers, trying to brute force to determine even your 15-word seed phrase, 2^165 possible combinations is also a huge number. Have you ever seen at least 2^160 ? This is a number of possible bitcoin ...


The mnemonic_sentence can be between 15 and 24 words. The mnemonic_second_factor is optional. So you can simply pass all your 24 words in as mnemonic_sentence and don't set the mnemonic_second_factor and you should be able to restore your wallet. Source: https://input-output-hk.github.io/cardano-wallet/api/edge/#operation/postWallet


As an architect/developer of your own crypto-wallet for personal use, you can declare your own list of 2048 words (although it's highly undesirable). However, if we talk about it in the sense of already existing products, such as Daedalus or Yoroi, it's impossible, because BIP39 wordlist is deeply integrated there.

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