Primitives

Public Key

32 bytes, derived using the Ed25519 algorithm.

Signature

64 bytes. The result of the Ed25519 sign: (privateKey, message) -> signature operation.

Address

Serialized in 20 bytes usually created by keeping the first 20 bytes of a hash or a public key.

Alternatively, Nimiq addresses can also be expressed in a a human-friendly form:

NQCC XXXX XXXX XXXX XXXX XXXX XXXX XXXX XXXX

• NQ as a prefix for “Nimiq”.
• Followed by a two digit checksum (CC) using the same algorithm like IBAN called MOD-97-10
• The remaining part (XXXX ...) is the actual address base32 encoded as 32 characters. To reduce possibility of confusion the letters “I” and “O” are omitted.

Hash

A hash can be of three types, but only two are used: Blake2b and Argon2d - SHA256 can be used for contracts, Blake2b is the default. When creating a light hash, Blake2b is used while when creating a hard hash as a proof of work, Argon2d (memory-hard) is being used. Independently, a hash is always 32 bytes long.

Variable integer

The first byte (type) is used to determind which size should be used. Very small numbers are stored straight in the first byte, bigger numbers are stored in 2 to 8 bytes.