[Thinine]

I need to hash an NSString using SHA1 and return the result. Here's the method I have now, which doesn't seem to work:

Code:
- (NSMutableString *) hashInfoString: (NSString *) aString
{
	NSMutableString *hashValue = [[NSMutableString alloc] initWithCapacity: 20];
	
	uint8_t md[SHA_DIGEST_LENGTH];
	
	unsigned char *stringToBeHashed[[aString length]];
	NSLog(@"stringToBeHashed allocated, going to coversion loop.");
	for (int i = 0; i < [aString length]; i++)
	{
		stringToBeHashed[i] = [aString characterAtIndex:i];
	}
	NSLog(@"Through conversion of NSString to char, string to be hashed is %C", stringToBeHashed);
	unsigned char *answer;
	answer = SHA1(stringToBeHashed, (unsigned long)6, md);
	NSLog(@"SHA1 function done, appending mutable string, answer is %C", answer);
	[hashValue appendFormat: @"%C", answer];
	NSLog(@"Mutable string appended, returning.");
	return hashValue;
}

Please be gentle, I really have no idea what I'm doing.

Basically, I need to know how to covert my NSString to a char, use SHA1 on that char, and turn the result back into an NSString. All this while I need to ensure I'm using the proper string formats.

Any thoughts on hashing a file in Cocoa are also appreciated.

[Thinine]

Okay, it looks like this now:

Code:
- (NSString *) hashInfoString: (NSString *) aString
{
	uint8_t md[SHA_DIGEST_LENGTH];
	
	const char* stringToBeHashed = [aString UTF8String];
	NSLog(@"Through conversion of NSString to char, string to be hashed is %s", stringToBeHashed);
	char* answer;
	answer = SHA1(stringToBeHashed, (unsigned long)[aString length], md);
	NSLog(@"SHA1 function done, appending mutable string, answer is %s", answer);
	NSString *hashValue = [NSString stringWithUTF8String: answer];
	NSLog(@"String created, returning.");
	return hashValue;
}

Problem is, the returned NSString is null.

[smeger]

The returned string 'answer' probably doesn't have its zero terminator, since there's no room for it. Also, "answer' and 'md' are probably the same pointer. Try these (untested) changes:

Code:
uint8_t md[SHA_DIGEST_LENGTH+1];
char *answer = SHA1(stringToBeHashed, strlen(stringToBeHashed), md);
md[SHA_DIGEST_LENGTH] = 0;