evalphobia/hierogolyph

package aesgcm

import (
    "fmt"
    "testing"

    "github.com/stretchr/testify/assert"
)

func TestGCM(t *testing.T) {
    a := assert.New(t)
    validKey := "12345678901234567890123456789012" // 32byte
    invalidKey := "X2345678901234567890123456789012"
    shortKey := "too short"
    longKey := validKey + "XYZ" // 35byte

    tests := []struct {
        text string
    }{
        {"a"},
        {"aaa"},
        {"あいうえお"},
        {""},
    }

    for _, tt := range tests {
        target := fmt.Sprintf("%+v", tt)

        _, err := Encrypt(tt.text, []byte(shortKey))
        if a.Error(err, "using short key") {
            a.Contains(err.Error(), "crypto/aes: invalid key size ", target, "using short key")
        }

        // encryption
        cipher1, err := Encrypt(tt.text, []byte(validKey))
        a.NoError(err, target)

        cipher2, err := Encrypt(tt.text, []byte(invalidKey))
        a.NoError(err, target)
        a.NotEqual(cipher1, cipher2, target, "using invalid key")

        // decryption
        plainText1, err := Decrypt(cipher1, []byte(validKey))
        a.NoError(err, target)
        a.Equal(tt.text, plainText1, target)

        _, err = Decrypt(cipher1, []byte(invalidKey))
        if a.Error(err, target) {
            a.Contains(err.Error(), "cipher: message authentication failed", target)
        }

        // long key should be used as first 32byte key.
        plainTextLongKey, err := Decrypt(cipher1, []byte(longKey))
        a.NoError(err, target)
        a.Equal(tt.text, plainTextLongKey, target)

        plainText2, err := Decrypt(cipher2, []byte(invalidKey))
        a.NoError(err, target)
        a.Equal(tt.text, plainText2, target)
    }
}