Zig Requires Chilkat v11.0.0+

Get EC Public Key from EC Private Key

See more ECC Examples

Demonstrates how to get an EC public key from an EC private key. Zig

const std = @import("std");
const chilkat = @import("chilkat");

pub fn main(init: std.process.Init) !void {
    const alloc = init.arena.allocator();

    // We have an ECC private key...
    // The contents of the private key PEM file look like this:

    //     -----BEGIN PRIVATE KEY-----
    //     MIGHAgEAMBMGByqGSM49AgEGCCqGSM49AwEHBG0wawIBAQQg3J8q/24D1sEKGdP9
    //     72MGYElLGpw/a56Y3t6pfON3uhShRANCAATlSmoizyhAwoYZAOuFBATl07/1RR54
    //     a1Dzfm16grxJe666AGKR+bSs24hk7TEpaeCTvT8YOOM3l+xKFg7zq6Q9
    //     -----END PRIVATE KEY-----

    const priv_key = try chilkat.PrivateKey.init();
    defer priv_key.deinit();
    priv_key.loadPemFile("qa_data/ecc/secp256r1-key-pkcs8.pem") catch {
        std.debug.print("{s}\n", .{try priv_key.getLastErrorText(alloc)});
        return;
    };

    // Get the public key.
    const pub_key = try chilkat.PublicKey.init();
    defer pub_key.deinit();
    priv_key.toPublicKey(pub_key) catch {};

    // Save the public key to a PEM file.
    pub_key.savePemFile(false, "qa_data/ecc/secp256r1-pubkey.pem") catch {
        std.debug.print("{s}\n", .{try pub_key.getLastErrorText(alloc)});
        return;
    };

    // The contents of the ECC public key PEM file look like this:

    //     -----BEGIN PUBLIC KEY-----
    //     MIIBSzCCAQMGByqGSM49AgEwgfcCAQEwLAYHKoZIzj0BAQIhAP////8AAAABAAAA
    //     AAAAAAAAAAAA////////////////MFsEIP////8AAAABAAAAAAAAAAAAAAAA////
    //     ///////////8BCBaxjXYqjqT57PrvVV2mIa8ZR0GsMxTsPY7zjw+J9JgSwMVAMSd
    //     NgiG5wSTamZ44ROdJreBn36QBEEEaxfR8uEsQkf4vOblY6RA8ncDfYEt6zOg9KE5
    //     RdiYwpZP40Li/hp/m47n60p8D54WK84zV2sxXs7LtkBoN79R9QIhAP////8AAAAA
    //     //////////+85vqtpxeehPO5ysL8YyVRAgEBA0IABOVKaiLPKEDChhkA64UEBOXT
    //     v/VFHnhrUPN+bXqCvEl7rroAYpH5tKzbiGTtMSlp4JO9Pxg44zeX7EoWDvOrpD0=
    //     -----END PUBLIC KEY-----

    std.debug.print("Success.\n", .{});
}