[−][src]Function extendhash::md5::extend_hash
pub fn extend_hash(
hash: [u8; 16],
length: usize,
additional_input: &[u8]
) -> [u8; 16]
Calculate an MD5 hash extension.
Arguments
hash
- The MD5 hash of some previous (unknown) datalength
- The length of the unknown data (without any added padding)additional_input
- Additional input to be included in the new hash.
Returns
This function returns the MD5 hash of the concatenation of the
original unknown data, its padding, and the additional_input
.
You can see the included (intermediate) padding by calling
md5::padding_for_length
.
Example
let secret_data = "This is a secret!".as_bytes(); let hash = md5::compute_hash(secret_data); let secret_data_length = secret_data.len(); // Now we try computing a hash extension, assuming that // `secret_data` is not available. We only need `hash` and // `secret_data_length`. let appended_message = "Appended message.".as_bytes(); let combined_hash = md5::extend_hash( hash, secret_data_length, appended_message); // Now we verify that `combined_hash` matches the // concatenation (note the intermediate padding): let mut combined_data = Vec::<u8>::new(); combined_data.extend_from_slice(secret_data); let padding = md5::padding_for_length(secret_data_length); combined_data.extend_from_slice(padding.as_slice()); combined_data.extend_from_slice(appended_message); assert_eq!( combined_hash, md5::compute_hash(combined_data.as_slice()));