ecdsaPublicFromPrivate
fn
ECDSAPublicKey ecdsaPublicFromPrivate(ECDSAPrivateKey key)Derives the ECDSA public key from a private scalar.
Computes Q = d * G over the private key's curve using the constant-time ladder. Container formats that carry only the scalar (SEC 1 ECPrivateKey without the optional public-key field, PKCS#8 without a public key) use this to recover the matching public key.
Parameters
key | The ECDSA private key; its curve name must be known and the scalar must lie in [1, n-1]. |
Returns
The matching public key on the same curve.
Throws
CryptoException for a null key, unknown curve, or
out-of-range scalar.