When I use this code to create a sha256 of a string
unsigned char hashedChars[32];
NSString *inputString;
inputString = [NSString stringWithFormat:@"hello"];
NSData * inputData = [inputString dataUsingEncoding:NSUTF8StringEncoding];
CC_SHA256(inputData.bytes, inputData.length, hashedChars);
It returns the hash correctly, but I need to insert a string like this \x00\x25\x53 and in this case, the function returns a sha256 of empty string because the specified encoding cannot be used to convert the receiver.
Now, my question is:How to insert this special characters for generate a correct hash? Thanks
Try this, it worked for me
1) To get a hash for plain text input
-(NSString*)sha256HashFor:(NSString*)input
{
const char* str = [input UTF8String];
unsigned char result[CC_SHA256_DIGEST_LENGTH];
CC_SHA256(str, strlen(str), result);
NSMutableString *ret = [NSMutableString stringWithCapacity:CC_SHA256_DIGEST_LENGTH*2];
for(int i = 0; i<CC_SHA256_DIGEST_LENGTH; i++)
{
[ret appendFormat:@"%02x",result[i]];
}
return ret;
}
2) To get hash for NSData
as input
Note:- I have used NSData
category, so the code is as follow
- (NSString *)SHA256_HASH {
//if (!self) return nil;
unsigned char hash[CC_SHA256_DIGEST_LENGTH];
if ( CC_SHA256([(NSData*)self bytes], [(NSData*)self length], hash) ) {
NSData *sha2 = [NSData dataWithBytes:hash length:CC_SHA256_DIGEST_LENGTH];
// description converts to hex but puts <> around it and spaces every 4 bytes
NSString *hash = [sha2 description];
hash = [hash stringByReplacingOccurrencesOfString:@" " withString:@""];
hash = [hash stringByReplacingOccurrencesOfString:@"<" withString:@""];
hash = [hash stringByReplacingOccurrencesOfString:@">" withString:@""];
// hash is now a string with just the 40char hash value in it
//NSLog(@"hash = %@",hash);
// Format SHA256 fingerprint like
// 00:00:00:00:00:00:00:00:00
int keyLength=[hash length];
NSString *formattedKey = @"";
for (int i=0; i<keyLength; i+=2) {
NSString *substr=[hash substringWithRange:NSMakeRange(i, 2)];
if (i!=keyLength-2)
substr=[substr stringByAppendingString:@":"];
formattedKey = [formattedKey stringByAppendingString:substr];
}
return formattedKey;
}
return nil;
}
It's important to know that you need to import:
#import <CommonCrypto/CommonDigest.h>
Hope this help!
If you love us? You can donate to us via Paypal or buy me a coffee so we can maintain and grow! Thank you!
Donate Us With