Arithmetic Coding and Huffman Coding are among the most common lossless compression algorithms. Their compression performances are relatively low as compared to some other tools. Still, they have widespread acceptance due to their high throughput rates. Both algorithms exploit symbol frequencies to achieve compression, which can be increased by redistributing the symbol statistics in a recoverable manner. We introduce a symbol redistributing scheme to serve as a preprocessor to improve compression. The preprocessor itself is an encryption machine providing compression and simple security. The preprocessor is succeeded by conventional compression tool to offer further compression. The overall scheme is called the Secure Compressor (SeCom). The system employing Arithmetic or Huffman Coding as compressor has been implemented and tested on sample texts in English and Turkish. Results show that SeCom considerably improves compression performances of both algorithms and introduces security to the system, as well.