SHA1 producing different result in Objective-C and C#

Question

I'm having trouble with hashing some string with SHA1 : C# and Objective C are producing a different result.

Objective C :

- (void) hashSHA1:(NSString*)input salt:(NSString*)salt
{
    const char *cstr = [[NSString stringWithFormat:@"%@%@",input, salt] cStringUsingEncoding:NSUTF8StringEncoding];
    NSData *data = [NSData dataWithBytes:cstr length:input.length];

    uint8_t digest[CC_SHA1_DIGEST_LENGTH];

    CC_SHA1(data.bytes, data.length, digest);

    NSMutableString* output = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH * 2];

    for(int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];

    NSLog("%@ : %@", input,output);
}

Output :

[self hashSHA1:@"F66791B5-33F1-49BB-AAA9-1D7A1CE51752" salt:@"salt"];
//Show : F66791B5-33F1-49BB-AAA9-1D7A1CE51752 : 435ba79fde87c45150fd053ca43ecce92fac54d3

C# :

static void HashSha1(string uid, string salt)
{
    var data = Encoding.UTF8.GetBytes(uid + salt);
    var sha1 = new SHA1CryptoServiceProvider();
    var hash = sha1.ComputeHash(data);

    var sb = new StringBuilder();
    foreach (var b in hash)
    {
        sb.Append(b.ToString("x2"));
    }

    Console.WriteLine("{0} : {1}", uid,sb.ToString());
}

Output :

HashSha1("F66791B5-33F1-49BB-AAA9-1D7A1CE51752", "salt");
//Show : F66791B5-33F1-49BB-AAA9-1D7A1CE51752 : 0853829f9df35d4171b7aff44ed62f0747523a3f

Did I miss something here ?

Thank you !

Answer 1

Looking at this line of Objective-C code, and admiting to not knowing much about Obj-C, shouldn't this line:

NSData *data = [NSData dataWithBytes:cstr length:input.length];

read:

NSData *data = [NSData dataWithBytes:cstr length:strlen(cstr)];

?