(Objective-C) Ed25519 Sign and Verify

Demonstrates how to create an Ed25519 signature, and then to verify it.

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

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#import <NSString.h>
#import <CkoPrivateKey.h>
#import <CkoBinData.h>
#import <CkoEdDSA.h>
#import <CkoPublicKey.h>

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

NSString *privKeyHex = @"1498b5467a63dffa2dc9d9e069caf075d16fc33fdd4c3b01bfadae6433767d93";
NSString *pubKeyHex = @"b7a3c12dc0c8c748ab07525b701122b88bd78f600c76342d27f25e5f92444cde";

CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];
// This example shows only one way of loading an Ed25519 private key.
// Chilkat can load other formats (JWK, PEM, ASN.1 DER, etc.)  
// You may do so by calling LoadAnyFormat or LoadAnyFormatFile.
BOOL success = [privKey LoadEd25519: privKeyHex pubKey: pubKeyHex];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

// The data to be signed...
CkoBinData *bd = [[CkoBinData alloc] init];
[bd AppendString: @"Message for Ed25519 signing" charset: @"utf-8"];

CkoEdDSA *eddsa = [[CkoEdDSA alloc] init];
NSString *hexSig = [eddsa SignBdENC: bd encoding: @"hexlower" privkey: privKey];

NSLog(@"%@%@",@"signature = ",hexSig);

// The expected output is: 6dd355667fae4eb43c6e0ab92e870edb2de0a88cae12dbd8591507f584fe4912babff497f1b8edf9567d2483d54ddc6459bea7855281b7a246a609e3001a4e08

// Verify the signature..
CkoPublicKey *pubKey = [[CkoPublicKey alloc] init];
success = [pubKey LoadEd25519: pubKeyHex];
if (success == NO) {
    NSLog(@"%@",pubKey.LastErrorText);
    return;
}

BOOL bVerified = [eddsa VerifyBdENC: bd encodedSig: hexSig enocding: @"hexlower" pubkey: pubKey];
if (bVerified == NO) {
    NSLog(@"%@",eddsa.LastErrorText);
    NSLog(@"%@",@"Failed to verify the signature.");
    return;
}

NSLog(@"%@",@"The Ed25519 signature is verified!");