Here's an Objective C method that'll return a SHA512 hex of a given string:

 
-(NSString*) sha512:(NSString*)input {
    const char *cstr = [input cStringUsingEncoding:NSUTF8StringEncoding];
    NSData *data = [NSData dataWithBytes:cstr length:input.length];
 
    uint8_t digest[CC_SHA512_DIGEST_LENGTH];
 
    CC_SHA512(data.bytes, data.length, digest);
 
    NSMutableString* output = [NSMutableString stringWithCapacity:CC_SHA512_DIGEST_LENGTH * 2];
 
    for(int i = 0; i < CC_SHA512_DIGEST_LENGTH; i++)
        [output appendFormat:@"%02x", digest[i]];
 
    return output;
 
}
 

You'll need to include:

 
    #include <CommonCrypto/CommonDigest.h>