mirror of https://github.com/schollz/croc.git
68 lines
1.5 KiB
Go
68 lines
1.5 KiB
Go
package crypt
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import (
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"crypto/aes"
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"crypto/cipher"
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"crypto/rand"
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"crypto/sha256"
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"fmt"
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"golang.org/x/crypto/pbkdf2"
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)
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// New generates a new key based on a passphrase and salt
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func New(passphrase []byte, usersalt []byte) (key []byte, salt []byte, err error) {
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if len(passphrase) < 1 {
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err = fmt.Errorf("need more than that for passphrase")
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return
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}
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if usersalt == nil {
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salt = make([]byte, 8)
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// http://www.ietf.org/rfc/rfc2898.txt
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// Salt.
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rand.Read(salt)
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} else {
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salt = usersalt
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}
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key = pbkdf2.Key([]byte(passphrase), salt, 100, 32, sha256.New)
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return
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}
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// Encrypt will encrypt using the pre-generated key
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func Encrypt(plaintext []byte, key []byte) (encrypted []byte, err error) {
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// generate a random iv each time
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// http://nvlpubs.nist.gov/nistpubs/Legacy/SP/nistspecialpublication800-38d.pdf
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// Section 8.2
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ivBytes := make([]byte, 12)
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rand.Read(ivBytes)
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b, err := aes.NewCipher(key)
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if err != nil {
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return
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}
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aesgcm, err := cipher.NewGCM(b)
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if err != nil {
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return
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}
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encrypted = aesgcm.Seal(nil, ivBytes, plaintext, nil)
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encrypted = append(ivBytes, encrypted...)
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return
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}
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// Decrypt using the pre-generated key
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func Decrypt(encrypted []byte, key []byte) (plaintext []byte, err error) {
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if len(encrypted) < 13 {
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err = fmt.Errorf("incorrect passphrase")
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return
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}
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b, err := aes.NewCipher(key)
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if err != nil {
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return
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}
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aesgcm, err := cipher.NewGCM(b)
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if err != nil {
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return
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}
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plaintext, err = aesgcm.Open(nil, encrypted[:12], encrypted[12:], nil)
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return
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}
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