md5

I have a situation where I have one VERY large file that I'm using the linux "split" command to break into smaller parts. Later I use the linux "cat" command to bring the parts all back together again. In the interim, however, I'm curious... If I get an MD5 fingerprint on the large file before splitting it, then later get the MD5 fingerprints on all the independent file parts that result from the split command, is there a way to take the independent fingerprints and somehow deduce that the sum or average (or whatever you like to all it) of their parts is equal to the fingerprint of the single

I need to crypt in md5 a string in my program. There is the lib openssl but I'm a newbie about it. How is possible crypt a string using that and where I can find a good doc that teach me how to use this lib, also with other function like aes? I've tried this code: int main() { unsigned char result[MD5_DIGEST_LENGTH]; const unsigned char* str; str = (unsigned char*)"hello"; unsigned int long_size = 100; MD5(str,long_size,result); } But the compiler told me: undefined reference to MD5 . Why is there and undefined reference to MD5 ? Morten Kristensen You should take a look at the documentation .

Is it possible to get the md5 of a file on a remote server? If so how? how about md5_file("http://remotelocation/file") It's not possible without downloading it, or the remote server providing the information (web service, HTML page, etc.) You can use md5(file_get_contents("http://remotelocation/file")) to download the file and calculate the md5 hash if your PHP installation is configured to open remote streams. But that will download the complete file. Well depends what you mean. There are two ways: You connect to the remote server and calculate the hash there (like ssh to the server). Get

I've got a byte array that was created using a hash function. I would like to convert this array into a string. So far so good, it will give me hexadecimal string. Now I would like to use something different than hexadecimal characters, I would like to encode the byte array with these 36 characters: [a-z][0-9] . How would I go about? Edit: the reason I would to do this, is because I would like to have a smaller string, than a hexadecimal string. Jon I adapted my arbitrary-length base conversion function from this answer to C#: static string BaseConvert(string number, int fromBase, int toBase)

is it just the file contents that get hashed? Is there any way to include the file name and or metadata such as creation date into the hashing process? Charliemops In general, all the file hashers encrypts only the binary content of the file. You can prove this with the following process: Apply the md5 algorithm to a file Copy this file into other directory and change its name. Apply the md5 algorithm to the copy. Compare both of the results. They are equal! MD5 tools will generally work with the binary content of the file. But you are of course free to put the file name and modification time