BIP32 Support

We support generating signatures for a BIP32 child key. Perform keygen once, and generate signatures for all BIP32 child keys!

Perform Derive Child Public-Key

---

• Call SilentShard.ECDSA.deriveChildPublicKeyAsData or SilentShard.EdDSA.deriveChildPublicKeyAsData which returns Result of Success with Child Public-Key bytes as Data or Failure with error.
• You can get public key as various string formats :
  • Hex String - By using

    SilentShardDuo.ECDSA.deriveChildPublicKeyAsHex()
    //or
    SilentShardDuo.EdDSA.deriveChildPublicKeyAsHex()
  • Base64 String - By using

    SilentShardDuo.ECDSA.deriveChildPublicKeyAsBase64()
    //or
    SilentShardDuo.EdDSA.deriveChildPublicKeyAsBase64()
  • UrlSafeBase64 String -

    SilentShardDuo.ECDSA.deriveChildPublicKeyAsUrlSafeBase64()
    //or
    SilentShardDuo.EdDSA.deriveChildPublicKeyAsUrlSafeBase64()
    Result of Success with Child Public-Key as String in desired format or Failure with error

Example

---

ECDSA

Example.swift

let MESSAGE_HASH = "cfa1ff5424d14eb60614d7ddf65a32243d26ddf7000d10007853d7336395efe4"

func deriveChildPublicKeyUsingKeyshare(
        keyshare: Data, duoSession: DuoSession
) async -> Data? {

    // performing signature example for context
    let result = await duoSession.signature(
        keyshare: keyshare, message: MESSAGE_HASH,
        chainPath: "m"  // This is the default, use your desired path here. For e.g 'm/1/2'
    )
    // returns nil if operation fails or other flow you might have
    switch result {
        case .success(let dataBytes):
        do {
            // do something with bytes, Here, let's derive child public key in various formats
            // Assuming it as ECDSA

            // hex string
            let childPublicKeyAsHex = await SilentShardDuo.ECDSA
                .deriveChildPublicKeyAsHex(
                    keyshare,
                    derivationPath: "m/1"
            )

            // bytes
            let childPublicKeyAsData = await SilentShardDuo.ECDSA
                .deriveChildPublicKeyAsData(
                    keyshare,
                    derivationPath: "m/1"
            )

            // base64 string
            let childPublicKeyAsDataAsBase64String =
            await SilentShardDuo.ECDSA.deriveChildPublicKeyAsBase64(
                    keyshare,
            derivationPath: "m/1"
            )

            // url safe base64 string
            let childPublicKeyAsDataAsUrlSafeBase64String =
            await SilentShardDuo.ECDSA
                    .deriveChildPublicKeyAsUrlSafeBase64(
                keyshare,
                derivationPath: "m/1"
            )

            return dataBytes
        }
        case .failure(let error):
        do {
            // show error to user or abort process
            Swift.print(error)
            return nil
        }
    }
}

EdDSA

Example.swift

let MESSAGE_HASH = "cfa1ff5424d14eb60614d7ddf65a32243d26ddf7000d10007853d7336395efe4"

func deriveChildPublicKeyUsingKeyshare(
        keyshare: Data, duoSession: DuoSession
) async -> Data? {

    // performing signature example for context
    let result = await duoSession.signature(
        keyshare: keyshare, message: MESSAGE_HASH,
        chainPath: "m"  // This is the default, use your desired path here. For e.g 'm/1/2'
    )
    // returns nil if operation fails or other flow you might have
    switch result {
        case .success(let dataBytes):
        do {
            // do something with bytes, Here, let's derive child public key in various formats
            // Assuming it as ECDSA

            // hex string
            let childPublicKeyAsHex = await SilentShardDuo.EdDSA
                .deriveChildPublicKeyAsHex(
                    keyshare,
                    derivationPath: "m/1"
            )

            // bytes
            let childPublicKeyAsData = await SilentShardDuo.EdDSA
                .deriveChildPublicKeyAsData(
                    keyshare,
                    derivationPath: "m/1"
            )

            // base64 string
            let childPublicKeyAsDataAsBase64String =
            await SilentShardDuo.EdDSA.deriveChildPublicKeyAsBase64(
                    keyshare,
            derivationPath: "m/1"
            )

            // url safe base64 string
            let childPublicKeyAsDataAsUrlSafeBase64String =
            await SilentShardDuo.EdDSA
                    .deriveChildPublicKeyAsUrlSafeBase64(
                keyshare,
                derivationPath: "m/1"
            )

            return dataBytes
        }
        case .failure(let error):
        do {
            // show error to user or abort process
            Swift.print(error)
            return nil
        }
    }
}

• When duoSession.sign() is called with a derivationPath, the signature is generated for the specified BIP32 derivation path.
• derivationPath is a string that specifies the path to the child key. It defaults to 'm' (no derivation) if not provided.