portainer/api/crypto/aes.go

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package crypto
import (
"crypto/aes"
"crypto/cipher"
"io"
"golang.org/x/crypto/scrypt"
)
// NOTE: has to go with what is considered to be a simplistic in that it omits any
// authentication of the encrypted data.
// Person with better knowledge is welcomed to improve it.
// sourced from https://golang.org/src/crypto/cipher/example_test.go
var emptySalt []byte = make([]byte, 0, 0)
// AesEncrypt reads from input, encrypts with AES-256 and writes to the output.
// passphrase is used to generate an encryption key.
func AesEncrypt(input io.Reader, output io.Writer, passphrase []byte) error {
// making a 32 bytes key that would correspond to AES-256
// don't necessarily need a salt, so just kept in empty
key, err := scrypt.Key(passphrase, emptySalt, 32768, 8, 1, 32)
if err != nil {
return err
}
block, err := aes.NewCipher(key)
if err != nil {
return err
}
// If the key is unique for each ciphertext, then it's ok to use a zero
// IV.
var iv [aes.BlockSize]byte
stream := cipher.NewOFB(block, iv[:])
writer := &cipher.StreamWriter{S: stream, W: output}
// Copy the input to the output, encrypting as we go.
if _, err := io.Copy(writer, input); err != nil {
return err
}
return nil
}
// AesDecrypt reads from input, decrypts with AES-256 and returns the reader to a read decrypted content from.
// passphrase is used to generate an encryption key.
func AesDecrypt(input io.Reader, passphrase []byte) (io.Reader, error) {
// making a 32 bytes key that would correspond to AES-256
// don't necessarily need a salt, so just kept in empty
key, err := scrypt.Key(passphrase, emptySalt, 32768, 8, 1, 32)
if err != nil {
return nil, err
}
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
// If the key is unique for each ciphertext, then it's ok to use a zero
// IV.
var iv [aes.BlockSize]byte
stream := cipher.NewOFB(block, iv[:])
reader := &cipher.StreamReader{S: stream, R: input}
return reader, nil
}