1. A method for efficient calculation of both similarity search values and boundaries of digest blocks in a data deduplication system using a processor device in a computing environment, comprising: partitioning input data into data chunks; calculating a set of rolling hash values for each of the data chunks; using a single linear scan of the rolling hash values for producing both the similarity search values and the boundaries of the digest blocks; and using each of the rolling hash values to contribute to the calculation of the similarity search values and to the calculation of the boundaries of the digest blocks.