Secure Data Deduplication with Smaller Hash Values

Techniques for providing secure deduplication in a data storage system using smaller hash values. The techniques employ a keyed hash function to generate keyed hash values for data blocks received at the data storage system. The keyed hash function can generate keyed hash values having an acceptable probability of accidental collision, in which each keyed hash value requires a reduced number of bits to represent them. By representing each keyed hash value with a number of bits less than the number required for a cryptographic hash value, the impact that an index table in main memory has on the amount of free memory space available can be reduced, while still providing an acceptable probability of accidental collision. The keyed hash function can be implemented as a keyed universal hash function, which can reduce the number of processor cycles required to generate a keyed hash value for each received data block.