108 lines
1.8 KiB
Go
108 lines
1.8 KiB
Go
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//go:build !change
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package psycher
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import (
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"crypto/cipher"
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"crypto/rand"
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"slices"
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"testing"
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"github.com/stretchr/testify/require"
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)
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type slowCipher struct {
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keys [][]byte
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}
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var _ cipher.Block = (*slowCipher)(nil)
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func (c slowCipher) BlockSize() int {
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return 16
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}
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func (c slowCipher) Encrypt(dst, src []byte) {
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var idx int
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for srcI, b := range src {
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for ; b != 0; b /= 2 {
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if b%2 == 1 {
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for i := range dst {
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dst[i] ^= c.keys[idx][i]
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}
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}
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idx++
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}
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idx = (srcI + 1) * 8
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}
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}
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func (c slowCipher) Decrypt(_, _ []byte) {
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panic("something nerdy")
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}
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func genKeys() [][]byte {
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var keys [][]byte
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for i := range 128 {
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keys = append(keys, make([]byte, 16))
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_, _ = rand.Read(keys[i])
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}
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return keys
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}
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func TestCorrectness(t *testing.T) {
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keys := genKeys()
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solCipher, correctCipher := New(keys), slowCipher{keys: keys}
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for range 1000 {
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src := make([]byte, 16)
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_, _ = rand.Read(src)
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srcCopy := slices.Clone(src)
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dst1, dst2 := make([]byte, 16), make([]byte, 16)
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correctCipher.Encrypt(dst1, src)
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solCipher.Encrypt(dst2, srcCopy)
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require.Equal(t, src, srcCopy, "shouldn't modify src")
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require.Equal(t, dst1, dst2, "wrong Encrypt output")
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}
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}
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func benchCipher(b *testing.B, constructor func([][]byte) cipher.Block) {
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keys := genKeys()
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c := constructor(keys)
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const blocksLen = 1_000_000
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var blocks [][]byte
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for range blocksLen {
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src := make([]byte, 16)
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_, _ = rand.Read(src)
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blocks = append(blocks, src)
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}
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dst := make([]byte, 16)
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b.ReportAllocs()
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b.SetBytes(16)
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b.ResetTimer()
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for i := range b.N {
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c.Encrypt(dst, blocks[i%blocksLen])
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}
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}
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func BenchmarkSlowCipher(b *testing.B) {
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benchCipher(b, func(keys [][]byte) cipher.Block {
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c := slowCipher{keys: keys}
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return c
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})
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}
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func BenchmarkCipher(b *testing.B) {
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benchCipher(b, func(keys [][]byte) cipher.Block {
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c := New(keys)
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return c
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})
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}
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