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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 rng_entropy): MicroSuiEd25519

Generate a new Ed25519 keypair for Sui.

Creates a MicroSuiEd25519 instance with a 32-byte seed generated by the PRNG, initialized using the current system time XOR the supplied entropy byte. Function pointers for signing, retrieving keys, and deriving the Sui address are also assigned.

Parameters​

NameTypeDescription
rng_entropyuint8_tAdditional entropy byte mixed with the current system time to initialize the PRNG. Supply an unpredictable value when available.

Returns​

Example usage​

uint8_t rng_entropy = 234; // Example only; use an unpredictable byte from a hardware source when available.

MicroSuiEd25519 keypair = SuiKeypair_generate(rng_entropy);

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