#import <CommonCrypto/CommonDigest.h>
- (NSString *)md5StringFromData:(NSData *)data
{
void *cData = malloc([data length]);
unsigned char resultCString[16];
[data getBytes:cData length:[data length]];
CC_MD5(cData, [data length], resultCString);
free(cData);
NSString *result = [NSString stringWithFormat:
@"%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X%02X",
resultCString[0], resultCString[1], resultCString[2], resultCString[3],
resultCString[4], resultCString[5], resultCString[6], resultCString[7],
resultCString[8], resultCString[9], resultCString[10], resultCString[11],
resultCString[12], resultCString[13], resultCString[14], resultCString[15]
];
return result;
}
reference from :http://stackoverflow.com/questions/1028742/compute-a-checksum-on-the-iphone-from-nsdata
