Code-string encryption method and apparatus, decryption method and apparatus, and recording medium

摘要

An original code string is decomposed into preview data (trial data) and high-quality data in a code-string decomposer. The high-quality data is separated into first data having an exactly or almost regular pattern and second data other than the first data by a high-quality data separator 1882. The second data is encrypted. The first data is not encrypted, or is encrypted by an encryption process other than that used for the second data. With this arrangement, important data is prevented from being deciphered.