i2pvanity

Generates I2P .b32.i2p vanity addresses (eepsites). It writes a standard i2pd-compatible 679-byte PrivateKeys .dat whose base32 address starts with a prefix you pick.

On a 32-thread box it does about 95 million candidates/sec, roughly 130x faster than a naive Python generator that regenerates the keypair every attempt. A 7-character prefix drops from an overnight run to about 6 minutes.

$ i2pvanity sam --out eepsite.dat --threads 30
generate: prefix='sam'  threads=30  expected~32768 attempts
HIT: sampeqazyp24kjb56vog3do426efrtrnrvsui6sjeecu26yzvhuq.b32.i2p
     37357 attempts in 0.001s (94000000 keys/sec, 30 threads)
wrote eepsite.dat (679 bytes, mode 0600)

Why it's fast

An I2P address is base32(sha256(destination)), and the destination holds two public keys: an ElGamal-2048 encryption key and an Ed25519 signing key. To search for a prefix you change one of them and re-hash.

The slow way is to vary the Ed25519 key: i2pd stores it as a seed, so every attempt is a full SHA-512 + scalar-mult keygen with no shortcut.

i2pvanity fixes the Ed25519 key and walks the ElGamal key instead. The ElGamal generator is 2, so the next public key is just the current one doubled mod p, y = (y + y) mod p, and the matching private key is x + 1. That's one big-int add per attempt instead of a keygen, and x is exactly what i2pd stores, so the .dat is valid. Same idea as mkp224o's point-addition trick, on the ElGamal side. Prefix matching works on the raw SHA-256 bits, so the loop never base32-encodes.

Threads	Python (naive)	i2pvanity	Speedup
1	47,096 keys/s	4.3M keys/s	~91x
30	747,572 keys/s	94.7M keys/s	~127x

Install

cargo install i2pvanity

Or build it:

git clone https://sambent.dev/sam/i2pvanity
cd i2pvanity
cargo build --release      # target/release/i2pvanity

For a static binary (Alpine etc.): cargo build --release --target x86_64-unknown-linux-musl.

Usage

i2pvanity <prefix> --out eepsite.dat [--threads N] [--uid N --gid N]
i2pvanity <prefix> --bench [--seconds N] [--threads N]

• <prefix> is 1 to 12 base32 chars (a-z, 2-7).
• --threads defaults to all cores.
• --uid/--gid chown the written file (useful when generating as root in a container).
• --bench measures throughput instead of writing a key.

On a terminal a long search prints a live progress line; when output is piped it stays quiet.

The file is Destination(391) || ElGamal_priv(256) || Ed25519_priv(32), mode 0600. Drop it in i2pd's destinations/ or point a tunnel's keys= at it.

Difficulty

Each extra character is 5 more bits, so 32x the work:

Prefix length	Avg attempts	Time at 95M/s (30 threads)
3 (sam)	32,768	instant
5	33.5M	under a second
6	1.07B	~11 seconds
7 (sambent)	34.4B	~6 minutes
8	1.1T	~3 hours

Verify a key

The address comes straight out of the file, so you can check it without this tool:

printf "%s.b32.i2p\n" "$(head -c 391 eepsite.dat | sha256sum | cut -d' ' -f1 \
  | xxd -r -p | base32 | tr -d = | tr A-Z a-z)"

i2pd-tools keyinfo eepsite.dat prints the same address if you have it.

Notes

The .dat is your private key, written in plaintext (i2pd needs it that way) at mode 0600. In-memory key material is zeroized on drop. The tool makes no network connections.

License

MIT OR Apache-2.0.