为什么golang加密示例不使用随机IV？ [关闭]

Question

According to CWE-329 NON-Random IV's allow for the possibility of a dictionary attack. However, in the AES crypto example, golang docs use a non-random IV:

ciphertext := make([]byte, aes.BlockSize+len(plaintext))
iv := ciphertext[:aes.BlockSize]

Is this implementation safe or should I use a random function to get my IV?

Answer 1

It is secure, because the IV is filled from a Cryptographically Secure Pseudo Random Number Generator (CSPRNG) which is /dev/urandom by default and provided from the OS. From the ExampleNewCBCEncrypter function:

iv := ciphertext[:aes.BlockSize]
if _, err := io.ReadFull(rand.Reader, iv); err != nil {
    panic(err)
}