Objective-C CommonCrypto: Decrypt Package Example.m

+(NSString *)decryptRSA:(NSString *)cipherString key:(SecKeyRef) privateKey {
	size_t plainBufferSize = SecKeyGetBlockSize(privateKey); 
	uint8_t *plainBuffer = malloc(plainBufferSize); NSData *incomingData = [NSData dataFromBase64String:cipherString]; 
	uint8_t *cipherBuffer = (uint8_t*)[incomingData bytes]; 
	size_t cipherBufferSize = SecKeyGetBlockSize(privateKey); 
	SecKeyDecrypt(privateKey,
		kSecPaddingOAEP, 
		cipherBuffer, 
		cipherBufferSize, 
		plainBuffer, 
		&plainBufferSize);
	NSData *decryptedData = [NSData dataWithBytes:plainBuffer length:plainBufferSize]; 
	NSString *decryptedString = [[NSString alloc] initWithData:decryptedData encoding:NSUTF8StringEncoding]; return decryptedString;
}