In beta 7 OpenSSL has been removed from the iPhone SDK. However, MD5 is still available. Simply import CommonCrypto as follows: #import < CommonCrypto/CommonDigest.h > Then add this C function to your objective-c class between the @implementation and @end statements (if you like). NSString* md5( NSString *str ) { const char *cStr = [str UTF8String]; unsigned char result[CC_MD5_DIGEST_LENGTH]; CC_M