A mnemonic seed, which can be referred to as a secret code, is an essential component of [[Self Custody|self custody]]. It's essentially a unique phrase of either 12 or 24 words typically generated by wallet software or open-source libraries. This secret code serves as the master key for accessing and managing digital assets stored in a blockchain wallet. The purpose of this mnemonic seed is to provide an effective way to back up, restore, or sweep a wallet. If you lose access to your device or forget your password, you can use this secret code to recover all the information related to your account. The length of the mnemonic seed (either 12 or 24 words) depends on the level of security desired; longer seeds offer more robust protection against potential threats. [[Seeds, Keys, Transaction Signing#BIP39]|BIP39]] (Bitcoin Improvement Proposal 39) has been widely adopted as using simple language mnemonics for wallet backups. These mnemonics are randomly generated sequences from a list of 2048 common English words which makes them easier for users to write down and remember than complex cryptographic strings. On Ethereum’s side, there isn't exactly an equivalent standard like BIP39, but it does have something similar called Inter-exchange Client Address Protocol (ICAP). ICAP uses Base58Check encoding instead of human-readable phrases like in BIP39 but still provides similar functionality with regards backup/recovery options for wallets. However, many Ethereum-based applications adopt standards like [[Seeds, Keys, Transaction Signing#BIP32/BIP39/BIP44 Standards|BIP32/BIP39/BIP44]] because they provide [[Wallet Types#Hierarchical Deterministic (HD)|hierarchical deterministic wallets (HD)]], meaning new addresses can be created from a single root seed, making management simpler since each transaction uses a different address.