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Keypair

MicroSui Object-style for handling Ed25519 keypairs in MicroSui.

Provides a small OO-like API (struct + function pointers) to work with Ed25519 keypairs in the context of the Sui blockchain.
This module provides core cryptographic utilities for creating and managing Sui-compatible keypairs and signatures.

Keypair capabilities: Generation of random Keypairs from fresh entropy, Initialize a keypair from a Bech32-encoded secret key string, Securely sign transaction messages using Ed25519, Retrieve the secret key (Bech32), public key (raw bytes), and derive the Sui-formatted address.

IMPORTANT NOTE:
✅ Compatibility & Support: This class is fully supported and production-stable (as of this documentation release) on any microcontroller and operating system.
⚠️ Functions returning strings or buffers use static internal storage. Results will be overwritten by subsequent calls and are not thread-safe.

Inspired by the Mysten Labs TypeScript SDK, adapted for embedded C.

File Location​

Defined in microsui-lib/src/Keypair.c

Indexs​

Constructors​

Methods​

Constructors​

SuiKeypair_generate​

SuiKeypair_generate(uint8_t seed_extra): MicroSuiEd25519

Generate a new Ed25519 keypair for Sui.

Creates a MicroSuiEd25519 instance with a random secret key derived from the current system time and an extra seed value. Function pointers for signing, retrieving keys, and deriving the Sui address are also assigned.

Parameters​

NameTypeDescription
seed_extrauint8_tExtra seed mixed with current time to initialize PRNG

Returns​

Example usage​

uint8_t seed_extra = 234584;    // In embedded systems, it's recommended to read the
                                // internal temperature sensor of the microcontroller,
                                // which most microcontrollers have.

MicroSuiEd25519 keypair = SuiKeypair_generate(seed_extra);

SuiKeypair_fromSecretKey​

SuiKeypair_fromSecretKey(const char *sk): MicroSuiEd25519

Initialize a MicroSuiEd25519 keypair from a Bech32 secret key string.

Decodes the provided Bech32 private key string and stores it in the new created struct.

Parameters​

NameTypeDescription
skconst char *Bech32-encoded secret key string

Returns​

Example usage​

const char* sui_secret_key_bech32 = "suiprivkey1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq509duq";

MicroSuiEd25519 keypair = SuiKeypair_fromSecretKey(sui_secret_key_bech32);

Methods​

signTransaction​

signTransaction(MicroSuiEd25519 *self, const char *msg): SuiSignature

Sign a transaction and execute it via the Sui RPC.

Sign a transaction message with the Ed25519 private key.
Converts a hex-encoded message string to bytes, signs it with Ed25519, and encodes the signature into Base64 format.

Parameters​

NameTypeDescription
selfMicroSuiEd25519 *Pointer to MicroSuiEd25519 instance
msgconst char *Hex-encoded transaction message string

Returns​

Example usage​

Given:

  • A valid secret key in bech32 format sui_secret_key_bech32: const char * type.
  • A valid Message to Sign string (in hexadecimal format) messageToSign: const char * type.

We can generate the signature as following:

const char* sui_secret_key_bech32 = "suiprivkey1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq509duq";
const char* messageToSign = "0000020008c0d8a700202e3d52393c9035afd1ef38abd7fce2dad71f0e276b522fb274f4e14d1d";

MicroSuiEd25519 keypair = SuiKeypair_fromSecretKey(sui_secret_key_bech32);

SuiSignature sig = keypair.signTransaction(&keypair, messageToSign);

if (sig.signature != NULL)
    // Is a valid Signature

toSuiAddress​

toSuiAddress(MicroSuiEd25519 *self): const char *

Derive the Sui address from the Ed25519 public key.

Computes the public key from the secret key, encodes it into a Sui address, and formats it as a hex string with the "0x" prefix.
The returned string is stored in a static buffer and will be overwritten by subsequent calls.

Parameters​

NameTypeDescription
selfMicroSuiEd25519 *Pointer to MicroSuiEd25519 instance

Returns​

  • const char * string.

Example usage​

Given:

  • A valid secret key in bech32 format sui_secret_key_bech32: const char * type.
const char* sui_secret_key_bech32 = "suiprivkey1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq509duq";

MicroSuiEd25519 keypair = SuiKeypair_fromSecretKey(sui_secret_key_bech32);
const char* suiAddress = keypair.toSuiAddress(&keypair);

if (suiAddress != NULL)
    // Sui Address is valid

getPublicKey​

getPublicKey(MicroSuiEd25519 *self): const uint8_t *

Get the public key derived from the private key.

Derives the 32-byte Ed25519 public key corresponding to the internal secret key.
The returned buffer is static and will be overwritten by subsequent calls.

Parameters​

NameTypeDescription
selfMicroSuiEd25519 *Pointer to MicroSuiEd25519 instance

Returns​

  • const uint8_t * string.

Example usage​

  • A valid secret key in bech32 format sui_secret_key_bech32: const char * type.
const char* sui_secret_key_bech32 = "suiprivkey1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq509duq";

MicroSuiEd25519 keypair = SuiKeypair_fromSecretKey(sui_secret_key_bech32);
const uint8_t* publicKey = keypair.getPublicKey(&keypair);

if (publicKey != NULL)
    // Public Key is valid

getSecretKey​

getSecretKey(MicroSuiEd25519 *self): const char *

Get the secret key in Bech32 string format.

Encodes the internal 32-byte secret key into a Bech32-encoded string.
The returned string is stored in a static buffer and will be overwritten by subsequent calls.

Parameters​

NameTypeDescription
selfMicroSuiEd25519 *Pointer to MicroSuiEd25519 instance

Returns​

  • const char * string.

Example usage​

Given:

  • A valid secret key in bech32 format sui_secret_key_bech32: const char * type.
const char* sui_secret_key_bech32 = "suiprivkey1qqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqq509duq";

MicroSuiEd25519 keypair = SuiKeypair_fromSecretKey(sui_secret_key_bech32);
const char* secretKey = keypair.getSecretKey(&keypair);

if (secretKey != NULL)
    // Secret Key is valid