No. 15; Updated March 2011. Click here to download and print a PDF version of this document. Approximately 120,000 children are adopted each year in the United States. Children with physical, developmental, or emotional handicaps who were once considered unadoptable are now being adopted (special needs adoptions). Adoption helps many of these children to grow up in permanent families rather than in foster homes or institutions.
A cryptographic hash function is a hash function which is considered practically impossible to invert, that is, to recreate the input data from its hash value alone.These one-way hash functions have been called the workhorses of modern cryptography.The input data is often called the message, and the hash value is often called the message digest or simply the digest. The ideal cryptographic hash function has four main properties:1  it is easy to compute the hash value for any given message. 2  it is infeasible to generate a message from its hash.hese one-way hash functions have been called the workhorses of modern cryptography. The input data is often called the message, and the hash value is often called the message digest or simply the digest.
A hash function is any function that can be used to map data of arbitrary size to data of fixed size.The values returned by a hash function are called hash values, hash codes, hash sums, or simply hashes. One use is a data structure called a hash table, widely used in computer software for rapid data lookup.Hash functions accelerate table or database lookup by detecting duplicated records in a large file.he values returned by a hash function are called hash values, hash codes, hash sums, or simply hashes. One use is a data structure called a hash table, widely used in computer software for rapid data lookup.