Are seed phrase generators safe?

Seed phrase generators are not safe for creating a wallet you plan to use. A seed phrase generator online or in a downloaded app makes the words somewhere you cannot see, so you cannot be sure the phrase was truly random or that nobody else kept a copy. Real wallets create the phrase themselves, ideally on a hardware device, and never need an outside tool.

Is an online seed phrase generator safe?

Under the BIP-39 standard, a 12-word phrase encodes 128 bits of random data and a 24-word phrase encodes 256 bits, plus a short checksum. That is why nobody can realistically guess a properly made phrase, as explained in can someone guess your seed phrase.

The protection depends on two things: the randomness must be strong, and the phrase must stay secret. A website can quietly record every phrase it shows you, or use a predictable random source so its operator can recreate the same words later. Either way, any funds you deposit can be taken.

What does a seed phrase generator and checker do?

Checkers usually ask you to paste a phrase to confirm it is valid or to look up its balance. A security write-up from wallet maker Ryder lists this as the most common theft method. Once you type a real phrase into the page, the operator has it and can empty the wallet within minutes. Validity is just a checksum built into the BIP-39 word list design, so there is no reason to hand a working phrase to a stranger's site.

Does a seed phrase generator with balance work?

No. The number of possible phrases is so large that randomly landing on a funded wallet is not realistic. Tools making this promise tend to follow a few patterns, according to the same Ryder analysis: stealing a phrase you enter, installing malware such as keyloggers or clipboard hijackers, showing fake balances and charging an "unlock" fee, or handing you a phrase the attacker controls.

A related trick posts seed phrases on social media that seem to unlock a wallet holding tokens. My Wallet's help center explains that when victims send coins to pay the network fee needed to withdraw, an automated script moves the deposit to the scammer straight away. More examples are in crypto phishing and wallet drainers.

Is a seed phrase generator from GitHub safe?

Open-source code can be reviewed, but that does not guarantee it is safe. In 2023, researchers found that the bx seed command in Libbitcoin Explorer, an established open-source Bitcoin toolkit, used a random number generator limited to 32 bits of internal entropy. The public vulnerability record, CVE-2023-39910, says attackers could recover private keys from affected wallets and that the flaw was exploited in June and July 2023. Unchained reported at least $900,000 stolen in what researchers named the Milk Sad incident.

Copies and forks add another risk, since anyone can publish a modified version with a hidden backdoor. The safer pattern is to let the wallet you will actually use generate the phrase, then write it down offline.