A true random number generator (TRNG) with 64 bit digital output was designed. This TRNG was built with the combination of a traditional Fibonacci ring oscillator and a Galois ring oscillator. By switching between the meta-stable state and the steady state, the true randomness was generated in the output bit steam. A post-processing module with DES algorithm was designed to increase the entropy of each bit, and make bit ‘0’ and bit ‘1’ distributed evenly. After FPGA verification, this TRNG was finally integrated into an USB disk controller chip with encryption/decryption functions by 110 nm CMOS process. The generated random sequence was tested under NIST SP800-22 standard. This silicon-proven chip was in mass-production status.