能够很好的实现文件的对称加密与解密，非常适合初学者学习，研究。-Can achieve the documents of the symmetric encryption and decryption, is ideal for beginners to learn and research.

哈希函数SHA-1的c实现，能正常运行。很实用，适合用来学习sha-1，希望对你有帮助。-A hash function is SHA-1 (c) achieve normal operation. Very practical, ideal for learning the sha-1, you want to help.