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Commit 691705a

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Rijul Gulati
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1 parent b12d5a7 commit 691705a

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5 files changed

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lines changed

5 files changed

+250
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‎andotp/andotp.go‎

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package andotp
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/sha1"
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"encoding/binary"
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"fmt"
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"io/ioutil"
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"math/rand"
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"golang.org/x/crypto/pbkdf2"
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)
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const (
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IV_LEN int = 12
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KEY_LEN int = 32
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ITERATION_LEN int = 4
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SALT_LEN int = 12
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MAX_ITERATIONS int = 160000
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MIN_ITERATIONS int = 140000
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)
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func Encrypt(plaintext []byte, password string) ([]byte, error) {
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var finalCipher []byte
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iter := make([]byte, ITERATION_LEN)
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iv := make([]byte, IV_LEN)
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salt := make([]byte, SALT_LEN)
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iterations := rand.Intn(MAX_ITERATIONS-MIN_ITERATIONS) + MIN_ITERATIONS
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binary.BigEndian.PutUint32(iter, uint32(iterations))
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_, err := rand.Read(iv)
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if err != nil {
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return nil, FormatError(err.Error())
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}
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_, err = rand.Read(salt)
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if err != nil {
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return nil, FormatError(err.Error())
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}
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secretKey := pbkdf2.Key([]byte(password), salt, iterations, KEY_LEN, sha1.New)
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block, err := aes.NewCipher(secretKey)
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if err != nil {
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return nil, FormatError(err.Error())
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}
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aesgcm, err := cipher.NewGCM(block)
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if err != nil {
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return nil, FormatError(err.Error())
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}
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cipherText := aesgcm.Seal(nil, iv, plaintext, nil)
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finalCipher = append(finalCipher, iter...)
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finalCipher = append(finalCipher, salt...)
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finalCipher = append(finalCipher, iv...)
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finalCipher = append(finalCipher, cipherText...)
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return finalCipher, nil
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}
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func Decrypt(encryptedtext []byte, password string) ([]byte, error) {
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iterations := encryptedtext[:ITERATION_LEN]
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salt := encryptedtext[ITERATION_LEN : ITERATION_LEN+SALT_LEN]
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iv := encryptedtext[ITERATION_LEN+SALT_LEN : ITERATION_LEN+SALT_LEN+IV_LEN]
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cipherText := encryptedtext[ITERATION_LEN+SALT_LEN+IV_LEN:]
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iter := int(binary.BigEndian.Uint32(iterations))
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secretKey := pbkdf2.Key([]byte(password), salt, iter, KEY_LEN, sha1.New)
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block, err := aes.NewCipher(secretKey)
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if err != nil {
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return nil, FormatError(err.Error())
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}
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aesgcm, err := cipher.NewGCM(block)
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if err != nil {
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return nil, FormatError(err.Error())
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}
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plaintextbytes, err := aesgcm.Open(nil, iv, cipherText, nil)
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if err != nil {
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return nil, FormatError(err.Error())
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}
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return plaintextbytes, nil
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}
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func FormatError(e string) error {
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return fmt.Errorf("error: %s", e)
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}
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func ReadFile(file string) ([]byte, error) {
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return ioutil.ReadFile(file)
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}

‎andotp/andotp_test.go‎

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package andotp_test
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import (
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"testing"
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"github.com/grijul/go-andotp/andotp"
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)
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const (
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jsonstr string = "[{\"secret\":\"SOMEAWESOMESECRET\",\"issuer\":\"SOMEAWESOMEISSUER\",\"label\":\"TESTLABEL\",\"digits\":6,\"type\":\"TOTP\",\"algorithm\":\"SHA1\",\"thumbnail\":\"Default\",\"last_used\":1000000000000,\"used_frequency\":0,\"period\":30,\"tags\":[]}]"
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password string = "testpass"
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)
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func TestEncryptDecrypt(t *testing.T) {
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encryptedtext, err := andotp.Encrypt([]byte(jsonstr), password)
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if err != nil {
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t.Error(err)
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}
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decryptedtext, err := andotp.Decrypt(encryptedtext, password)
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if err != nil {
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t.Error(err)
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}
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if string(decryptedtext) != jsonstr {
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t.Error("Encryption/Decryption failed. Text mismatch")
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}
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}

‎go.mod‎

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module github.com/grijul/go-andotp
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go 1.16
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require (
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golang.org/x/crypto v0.0.0-20210506145944-38f3c27a63bf
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golang.org/x/term v0.0.0-20210503060354-a79de5458b56
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)

‎go.sum‎

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golang.org/x/crypto v0.0.0-20210506145944-38f3c27a63bf h1:B2n+Zi5QeYRDAEodEu72OS36gmTWjgpXr2+cWcBW90o=
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golang.org/x/crypto v0.0.0-20210506145944-38f3c27a63bf/go.mod h1:P+XmwS30IXTQdn5tA2iutPOUgjI07+tq3H3K9MVA1s8=
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golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
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golang.org/x/sys v0.0.0-20201119102817-f84b799fce68 h1:nxC68pudNYkKU6jWhgrqdreuFiOQWj1Fs7T3VrH4Pjw=
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golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
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golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
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golang.org/x/term v0.0.0-20210503060354-a79de5458b56 h1:b8jxX3zqjpqb2LklXPzKSGJhzyxCOZSz8ncv8Nv+y7w=
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golang.org/x/term v0.0.0-20210503060354-a79de5458b56/go.mod h1:tfny5GFUkzUvx4ps4ajbZsCe5lw1metzhBm9T3x7oIY=
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golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
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golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

‎main.go‎

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package main
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import (
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"flag"
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"fmt"
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"io/ioutil"
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"os"
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"syscall"
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"github.com/grijul/go-andotp/andotp"
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"golang.org/x/term"
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)
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func main() {
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flag.Usage = func() {
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fmt.Printf("Usage: %s -i <INPUT_FILE> {-e|-d} [-o <OUT_FILE>] [-p PASSWORD]\n\n", os.Args[0])
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flag.PrintDefaults()
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}
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encryptPtr := flag.Bool("e", false, "Encrypt file.")
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decryptPtr := flag.Bool("d", false, "Decrypt file")
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inputFilePtr := flag.String("i", "", "Input File")
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passwordPtr := flag.String("p", "", "Encryption Password. This option can be skipped to get password prompt.")
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outputFilePtr := flag.String("o", "", "Output File. If no file is provided, output is printed to STDOUT")
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flag.Parse()
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if *inputFilePtr == "" {
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fmt.Println(andotp.FormatError("No input file provided\nSee -h for available options."))
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os.Exit(0)
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}
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if *encryptPtr && *decryptPtr {
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fmt.Println(andotp.FormatError("Please provide any one of encrypt (-e) or decrypt (-d) flag"))
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os.Exit(0)
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}
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if *passwordPtr == "" {
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*passwordPtr = getPassword()
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if *passwordPtr == "" {
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fmt.Println(andotp.FormatError("No password provided."))
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os.Exit(0)
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}
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}
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if *encryptPtr {
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plaintext, err := andotp.ReadFile(*inputFilePtr)
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if err != nil {
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fmt.Print(err.Error())
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os.Exit(0)
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}
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filecontent, err := andotp.Encrypt(plaintext, *passwordPtr)
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if err != nil {
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fmt.Print(err.Error())
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os.Exit(0)
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}
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processfile(filecontent, *outputFilePtr)
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} else if *decryptPtr {
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encryptedtext, err := andotp.ReadFile(*inputFilePtr)
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if err != nil {
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fmt.Print(err.Error())
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os.Exit(0)
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}
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filecontent, err := andotp.Decrypt(encryptedtext, *passwordPtr)
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if err != nil {
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fmt.Print(err.Error())
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os.Exit(0)
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}
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processfile(filecontent, *outputFilePtr)
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} else {
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fmt.Println(andotp.FormatError("Please provide encrypt (-e) or decrypt (-d) flag"))
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os.Exit(0)
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}
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}
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func processfile(filecontent []byte, outputfile string) {
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if outputfile == "" {
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fmt.Printf("%s", filecontent)
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} else {
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ioutil.WriteFile(outputfile, filecontent, 0644)
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}
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}
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func getPassword() string {
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fmt.Print("Password: ")
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pass, err := term.ReadPassword(int(syscall.Stdin))
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if err != nil {
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fmt.Print(andotp.FormatError(err.Error()))
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}
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fmt.Print("\n")
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return string(pass)
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}

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