SHA1 outputs in Java and Objective-c vary within a loop

Question

i happen to be getting varying outputs when i call the digest method (in java) and CC_SHA1 (in Objective-c multiple times.

Please note that when the loop isn't used, i'm getting matching outputs.

The following are the implementations i'm currently employing.

Objective C Snippet

NSString *haha= [NSString stringWithFormat:@"%@%@",sPassPhrase,sSaltValue];
NSData *abKey0 = [haha dataUsingEncoding:NSASCIIStringEncoding];
NSMutableData *abKey = [NSMutableData dataWithData:abKey0];

unsigned char digest[20];
for(int i=1;i<iIterations;i++)
{
    CC_SHA1(abKey.bytes, abKey.length, digest);
    abKey = [NSMutableData dataWithBytes:digest length:20];
}

Java snippet

String haha = sPassPhrase + sSaltValue;
byte[] abKey = haha.getBytes("US-ASCII");
MessageDigest oSHA1 = MessageDigest.getInstance("SHA-1");

for (int i = 1; i <= iIterations; i++) 
{
    abKey = oSHA1.digest(abKey);
}

This has me scouring the api docs for several hours now but i'm not able to find anything helpful.

Answer 1

One obvious differences is that you are doing one iteration less in objective C than you are doing in Java. Look at the '<' versus "<=' in the two for loops.