9.2. Key Pair Format

Iroha uses key pairs (.pub and .priv keys) to sign transactions – every account has at least 1 pair. Some accounts (if quorum is more than 1) might have more Signatories that sign transactions – and each Signatory has a pair of keys. Cryptographic algorithms use those keys – and in Iroha we provide you with a choice – which algorithms to use.

9.2.1. Supported Crypto Algorithms

Natively, HL Iroha uses a custom algorithm – Ed25519 with SHA-3. These keys are supported by all versions of Iroha, including the old ones. But as we all know, we need more universal options as well – that is why Iroha has HL Ursa integration – it is a library with different crypto algorithms, that allows to work with Iroha using more mainstream keys. Ursa provides Iroha with support of standard Ed25519 with SHA-2 algorithm. Public Keys

To provide easy solution that would allow using different algorithms without “breaking” backward compatibility, we introduced multihash format for public keys in Iroha. You can learn more about multihash here.

Generally, to use keys, different from the native SHA-3 ed25519 keys, you will need to bring them to this format:

<varint key type code><varint key size in bytes><actual key bytes>


In multihash, varints are the Most Significant Bit unsigned varints (also called base-128 varints).

If Iroha receives a standard public key of 32 bytes, it will treat is as a native Iroha key. If it receives a multihash public key, it will treat it based on the table below.

Right now, Iroha “understands” only one multihash key format:

Name Tag Code Description
ed25519-pub key 0xed Ed25519 public key

Examples of public keys in Iroha:

type code length data what Iroha recognises
multihash key ED01 20 62646464c35383430b… ed25519/sha2
raw 32 byte key 716fe505f69f18511a… ed25519/sha3

Note that code 0xED is encoded as ED01 by the rules of multihash format. Private Keys

Private keys in Ursa are represented by concatenation of a private key and a public key – without multihash prefixes.