EOS Hashes
We seem to use hashes everywhere when writing smart contracts… after all, they are the foundation of blockchains. But how do we go about creating a hash in EOS? Let’s start by including a new library.
include <eosiolib/crypto.h>
Notice the .h file extension in our crypto.h include? This means we’re using a C library and not C++, so our methods will be expecting C type inputs. Now let’s create an action which will take a string as input, hash our string and then print the result.
We will start by making allocating a checksum256 reference.
checksum256 sum{}
Then use our eosio::sha256(CHARS,LENGTH,REFERENCE) method.
sha256(const_cast<char*>(str.c_str()), str.size(), &sum);
Now all that remains is printing the result.
printhex(&sum, sizeof(sum));
And that’s it! The full code for this example can be found on GitHub.