(Objective-C) Get an EC Key in Raw Hex Format

Demonstrates how to get the private and public key parts of an EC (ECDSA) key in lowercase hex formmat.

Note: This example requires Chilkat v9.5.0.83 or greater.

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#import <CkoPrivateKey.h>
#import <CkoStringBuilder.h>
#import <NSString.h>

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

// Load an EC key from some format..
CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];

// This loads an ECDSA key from an unencrypted PEM file (no password required).
BOOL success = [privKey LoadAnyFormatFile: @"qa_data/ecc/openssl_ecc_privKey.pem" password: @""];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

// The key type should be "ecc" to indicate an EC key.
NSLog(@"%@%@",@"key type = ",privKey.KeyType);

// What is the size of the private key in bits?
NSLog(@"%@%d",@"size in bits = ",[privKey.BitLength intValue]);

// Get the private and public EC key parts in raw hex format:
CkoStringBuilder *sbPubKeyHex = [[CkoStringBuilder alloc] init];
NSString *privKeyHex = [privKey GetRawHex: sbPubKeyHex];

// If the private key size in bits is 256, then we should have a 32-byte key (a 64 character hex string).
NSLog(@"%@%@",@"private key = ",privKeyHex);

// The public key is composed of the "x" and "y" parts, and is composed like this:  04||HEX(x)||HEX(y)
NSLog(@"%@%@",@"public key = ",[sbPubKeyHex GetAsString]);

// Sample output:
// key type = ecc
// size in bits = 256
// private key = ced36f2ba3332be439f79143d69937fc52494cd38e45243c3ea05db183919f1b
// public key = 045b4edcd501831740895f5907feabb71587076a6314d9d5141f9f8c33a478b8ce08b8dfd2a091eb6355803d7e729876c790bc0b176f2015f3bb103813753f676a