mirror of https://github.com/schollz/croc.git
62 lines
1.5 KiB
Go
62 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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"golang.org/x/crypto/pbkdf2"
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)
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// Encryption stores the data
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type Encryption struct {
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Encrypted, Salt, IV []byte
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}
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// Encrypt will generate an encryption
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func Encrypt(plaintext []byte, passphrase []byte, dontencrypt ...bool) Encryption {
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if len(dontencrypt) > 0 && dontencrypt[0] {
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return Encryption{
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Encrypted: plaintext,
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Salt: []byte("salt"),
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IV: []byte("iv"),
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}
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}
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key, saltBytes := deriveKey(passphrase, nil)
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ivBytes := make([]byte, 12)
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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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rand.Read(ivBytes)
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b, _ := aes.NewCipher(key)
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aesgcm, _ := cipher.NewGCM(b)
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encrypted := aesgcm.Seal(nil, ivBytes, plaintext, nil)
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return Encryption{
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Encrypted: encrypted,
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Salt: saltBytes,
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IV: ivBytes,
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}
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}
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// Decrypt an encryption
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func (e Encryption) Decrypt(passphrase []byte, dontencrypt ...bool) (plaintext []byte, err error) {
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if len(dontencrypt) > 0 && dontencrypt[0] {
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return e.Encrypted, nil
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}
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key, _ := deriveKey(passphrase, e.Salt)
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b, _ := aes.NewCipher(key)
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aesgcm, _ := cipher.NewGCM(b)
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plaintext, err = aesgcm.Open(nil, e.IV, e.Encrypted, nil)
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return
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}
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func deriveKey(passphrase []byte, salt []byte) ([]byte, []byte) {
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if salt == 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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}
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return pbkdf2.Key([]byte(passphrase), salt, 100, 32, sha256.New), salt
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}
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