Cloak/internal/common/crypto.go
2020-04-14 14:14:51 +01:00

63 lines
1.4 KiB
Go

package common
import (
"crypto/aes"
"crypto/cipher"
"crypto/rand"
"io"
"time"
log "github.com/sirupsen/logrus"
)
func AESGCMEncrypt(nonce []byte, key []byte, plaintext []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aesgcm, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
return aesgcm.Seal(nil, nonce, plaintext, nil), nil
}
func AESGCMDecrypt(nonce []byte, key []byte, ciphertext []byte) ([]byte, error) {
block, err := aes.NewCipher(key)
if err != nil {
return nil, err
}
aesgcm, err := cipher.NewGCM(block)
if err != nil {
return nil, err
}
plain, err := aesgcm.Open(nil, nonce, ciphertext, nil)
if err != nil {
return nil, err
}
return plain, nil
}
func CryptoRandRead(buf []byte) {
RandRead(rand.Reader, buf)
}
func RandRead(randSource io.Reader, buf []byte) {
_, err := randSource.Read(buf)
if err == nil {
return
}
waitDur := [10]time.Duration{5 * time.Millisecond, 10 * time.Millisecond, 30 * time.Millisecond, 50 * time.Millisecond,
100 * time.Millisecond, 300 * time.Millisecond, 500 * time.Millisecond, 1 * time.Second,
3 * time.Second, 5 * time.Second}
for i := 0; i < 10; i++ {
log.Errorf("Failed to get cryptographic random bytes: %v. Retrying...", err)
_, err = rand.Read(buf)
if err == nil {
return
}
time.Sleep(time.Millisecond * waitDur[i])
}
log.Fatal("Cannot get cryptographic random bytes after 10 retries")
}