In cryptography, SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash
function designed by the United States National Security Agency and is a
U.S. Federal Information Processing Standard published by the United States
NIST. SHA1 is used in many places to generate a unique Hash value
representing a string or file. It is widely used in place of MD4 and MD5 ash
a more secure hash value. While not as secure as SHA256, it is still used in
many places for data integrity, version control, and other features that
need an unique one-way signatures.
In part two of this series, Peggy and Jeff will guide us to a better
understanding of the hashing mechanism, from modulo and separation, all the
way to overflow and resizing.
The MultiValue Database and its descendants are noted for their flexibility
in handling of data. This is a radical departure from traditional,
fixed-length data records found in other SQL databases, and provides a very
attractive environment for business applications. This flexible structure
places demands on the underlying data storage mechanisms.
To meet these demands, MultiValue databases use a hashed file structure.
This series of articles will examine in depth the specifics of hashed files
as implemented in the UniVerse and UniData environments.