About
SolanaKeys.fun was inspired by the now defunct directory.io. Just like this website, directory.io contained pages of all bitcoin private keys. It caused quite the fuss when it was shared on the internet back in 2013 with the title "All Bitcoin private keys leaked".
2^256
If you want to try to wrap your head around how many Solana private keys there actually are, I can recommend watching this video:
Generating private keys
SolanaKeys.fun contains all private keys of Solana. These keys aren't stored on the server, that would take an impossible amount of disk space. Instead, the keys are generated whenever a page is opened.
The seeds used to generate the private keys are derived from the page number. For example, on page 10, the first seed is:
(10 - 1) * 32 + 0 = 288
Pages contain 32 keys each, so the last seed on page 10 is:
(10 - 1) * 32 + 31 = 319
This simple formula is repeated for each page, until the maximum seed of 2^256 is reached. The seed is then used to deterministically generate an Ed25519 keypair.
Technology
The code that generates the keys runs entirely in your browser using JavaScript. Solana uses the Ed25519 elliptic curve for its cryptography, which provides 256-bit security.
Each private key is 32 bytes (256 bits) and the corresponding public key is also 32 bytes. The public key is then encoded in Base58 format to create the familiar Solana wallet address that you see on explorers like Solscan.
The derivation follows the BIP44 standard used by wallets like Phantom, Solflare, and Backpack, with the path m/44'/501'/0'/0'.
Security
Despite containing every possible private key, this website poses no security threat to Solana users. The probability of randomly landing on a page containing an active wallet is approximately:
1 in 10^68 (effectively zero)
To put this in perspective, there are only about 10^80 atoms in the observable universe. You would have better odds of randomly selecting the same atom twice from the entire universe than finding an active Solana wallet on this site.
Warning
Never use a private key from this website.
These keys are generated deterministically and are publicly visible. Anyone who visits the same page can see the same keys. Only use keys generated by trusted wallet software with proper random number generation.