split key

split key (plural split keys)

1. (engineering) A key split at one end like a split pin, for the same purpose.
   • 1869, Cameron Knight, The Mechanician and Constructor for Engineers:

     A split pin is also a split key, because both are used to lock or fasten pieces of machinery together.

   • 1907, Official Gazette of the United States Patent Office, page 1292:

     In a rail-stay, the combination of a bar, with rail-clamping means associated with the bar at each end, a spilt key to hold said means in engagement with the rail flange, and a fixed projection to force the leaves of the split key apart.

   • 1914, Dominion Law Reports - Volume 14, page 703:

     I am of the opinion, upon the evidence, that, although provision was made in the bolt for the split key, as a matter of fact no split key had ever been inserted.

2. (computing) A key value used to identify where to split the children of a parent node in a B-tree or similar data structure.
   • 1990, Hector Garcia-Molina, H. V. Jagadish, Proceedings of the 1990 ACM SIGMOD International Conference on Management of Data., page 353:

     As with B+-trees, records with keys greater than or equal to the split key go to a new current node, records with keys less than the split key remain in the original node.

   • 2014, Jason Venner, Sameer Wadkar, Madhu Siddalingaiah, Pro Apache Hadoop, →ISBN, page 310:

     The region is split into two logical daughter regions. The split is not done physically at this point to make the splitting process fast. The split is maintained as a split key, which is a key in the middle of the key range maintained for the region.

   • 2016, Christopher G. Healey, Disk-Based Algorithms for Big Data, →ISBN:

     Take the key in the parent node that splits the left sibling and the leaf, the split key, and insert it into the leaf.

3. (cryptography) A cryptographic key that is divided into two or more values that individually cannot be used to deduce the entire key.
   • 1997, Cryptography and Privacy Sourcebook, →ISBN, page 15:

     Moreover, even those systems (such as split key systems) that can decrease these risks, do so with a marked increase in cost.

   • 2007, Matt Blaze, Financial Cryptography, →ISBN, page 233:

     A toolkit for split key cryptography in and of itself is (almost) a byproduct of developing ultra-high assurance applications such as root certifying authorities.

   • 2014, Michel Abdalla, Roberto De Prisco, Security and Cryptography for Networks, →ISBN, page 45:

     Camenisch et al. [CCGS10] define, among other things, split key exchange and give a construction based on the decisional Diffie-Hellman assumption.