Code reviewHardcr-g444

Subject Crypto misuseLevel Senior–Staff~26 minCommon in Security · Distributed systems interviewsIndustries Software development, Technology

Question

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.

Learn the concepts

Talk through your review

Code to reviewgo

1var counter uint642 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), nil10}

Run or narrate your approach, then ask the coach.