What is digested data?

Question

I'm learning OpenSSL and I found this method BIO_f_md() in the libtrary documentation: http://www.openssl.org/docs/crypto/BIO_f_md.html where it says:

Any data written or read through a digest BIO using BIO_read() and BIO_write() is digested.

What does digest mean? What is digested data?

Answer 1

In cryptology lingo, a digest is simply a hash value - i.e. the output of a cryptographic hash function. Usually, the data itself is referred to as the "message", and the hash value of the data is called the "digest" or "message-digest". So, digested means "hashed".