GCM message encryption

Code reviewSecurityDistributed systemsSenior–Staff~26 min

Review this Go message encryptor using AES-GCM with a counter nonce.

What a strong answer looks like

Separate real bugs from style. Rank issues by severity, point at the root cause rather than the symptom, and suggest a concrete fix, specific and kind.

0:00 of about 26 min

Mark a line and say what kind of problem it is.0 findings

1var counter uint64

3func Encrypt(key, plaintext []byte) ([]byte, error) {

4 block, _ := aes.NewCipher(key)

5 gcm, _ := cipher.NewGCM(block)

6 nonce := make([]byte, gcm.NonceSize())

7 binary.BigEndian.PutUint64(nonce[4:], counter)

8 counter++

9 return gcm.Seal(nil, nonce, plaintext, nil), nil

10}

Which questions mattered is sealed until you submit. Telling you now would just be handing over the edge cases.