Introduction - If you have any usage issues, please Google them yourself
To write a file encryption and decryption tool (VC9+ OPENSSL)
CA procedures:
Generates two RSA key pairs, respectively, save for the PEM format, password-protected private key, the file named "RSAPrivateKey.pem" and "RSAPublicKey.pem".
Encryption:
The specified plaintext file encryption, secret self-definition file formats require the document to use symmetric algorithms (3des) encryption, symmetric key (KEY) is randomly generated, random key to use "RSAPrivateKey.pem" public key encryption, stored in the ciphertext header inside (KEY1) summary of the calculation of the plaintext file to do (HASH), the calculation results with the "RSAPublicKey.pem" private key encryption (SIGN), into ciphertext in the file header file header if there is express The original length of the message.
Decryption:
Decrypt the ciphertext into a plaintext file documents, processes and encrypt the contrary, the first to use "RSAPrivateKey.pem" decrypt the private key (KEY1) data, derived random k