A decoder for decoding a message using an arbitrary-side growing (ASG) Huffman tree including a plurality of codewords and symbols includes a database, a processing module, and a bit pattern matching module. The database stores a plurality of parameters corresponding to the ASG Huffman tree divided into several sub-trees according to a Hashemian cut operation and a bits-pattern-Xor (BPX) operation. The plurality of parameters include a bit pattern of a sub-tree of the ASG Huffman tree divided according to the BPX operation and a code length of the bit pattern. The processing module receives a bit stream corresponding to the ASG Huffman tree from an encoder. The bit pattern matching module selects bits from the bit stream according to the code length of the bit pattern and decodes the selected bits into a symbol in the ASG Huffman tree by comparing the selected bits with the bit pattern.