(Objective-C) RSA Sign using Base64 Private Key

Signs a string using a non-encrypted RSA private key in base64 encoding. Returns the RSA signature as a base64 string.

Note: This example requires Chilkat v11.0.0 or greater.

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

BOOL success = NO;

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

CkoPrivateKey *privKey = [[CkoPrivateKey alloc] init];

CkoStringBuilder *sbPem = [[CkoStringBuilder alloc] init];
[sbPem AppendLine: @"-----BEGIN RSA PRIVATE KEY-----" crlf: YES];
[sbPem AppendLine: @"MIIC .... j5A==" crlf: YES];
[sbPem AppendLine: @"-----END RSA PRIVATE KEY-----" crlf: YES];

success = [privKey LoadPem: [sbPem GetAsString]];
if (success == NO) {
    NSLog(@"%@",privKey.LastErrorText);
    return;
}

CkoRsa *rsa = [[CkoRsa alloc] init];

success = [rsa UsePrivateKey: privKey];
if (success == NO) {
    NSLog(@"%@",rsa.LastErrorText);
    return;
}

CkoBinData *bd = [[CkoBinData alloc] init];
[bd AppendString: @"12345678" charset: @"utf-8"];

success = [rsa SignRawBd: bd];
if (success == NO) {
    NSLog(@"%@",rsa.LastErrorText);
    return;
}

// Get the base64 RSA signature.
NSLog(@"%@",[bd GetEncoded: @"base64"]);

success = [rsa VerifyRawBd: bd];
if (success == NO) {
    NSLog(@"%@",rsa.LastErrorText);
    return;
}

NSString *strOriginal = [bd GetString: @"utf-8"];
NSLog(@"%@",strOriginal);