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Validating Poly1305 Cryptographic Authentication in Telegram

This test suite validates the Poly1305 message authentication code implementation in Go, focusing on verification of cryptographic operations and memory alignment handling.

Test Coverage Overview

The test suite provides comprehensive coverage of Poly1305 authentication functionality including:

Basic sum operations with aligned and unaligned memory
Stress testing with extensive iteration counts
Validation of cryptographic output against known test vectors
Performance benchmarking across different input sizes

Implementation Analysis

The testing approach implements both standard and edge-case scenarios using Go’s testing framework. Key patterns include:

Hex-encoded test vectors for input validation
Memory alignment testing using unsafe pointers
Separate test functions for aligned and unaligned data
Comprehensive benchmarking suite with varied input sizes

Technical Details

Testing infrastructure includes:

Go testing framework with benchmark support
Custom test struct for managing cryptographic test vectors
Unsafe package for memory alignment manipulation
Hex encoding/decoding for test data handling
Command-line flags for optional stress testing

Best Practices Demonstrated

The test suite exemplifies several testing best practices:

Separation of concerns between test types (unit, stress, benchmark)
Thorough edge case coverage including memory alignment
Parameterized testing for different input configurations
Clear test data organization and error reporting
Performance measurement with varied input sizes

drklo/telegram

TMessagesProj/jni/boringssl/ssl/test/runner/poly1305/poly1305_test.go

            
// Copyright 2012 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package poly1305

import (
	"encoding/hex"
	"flag"
	"testing"
	"unsafe"
)

var stressFlag = flag.Bool("stress", false, "run slow stress tests")

type test struct {
	in  string
	key string
	tag string
}

func (t *test) Input() []byte {
	in, err := hex.DecodeString(t.in)
	if err != nil {
		panic(err)
	}
	return in
}

func (t *test) Key() [32]byte {
	buf, err := hex.DecodeString(t.key)
	if err != nil {
		panic(err)
	}
	var key [32]byte
	copy(key[:], buf[:32])
	return key
}

func (t *test) Tag() [16]byte {
	buf, err := hex.DecodeString(t.tag)
	if err != nil {
		panic(err)
	}
	var tag [16]byte
	copy(tag[:], buf[:16])
	return tag
}

func testSum(t *testing.T, unaligned bool, sumImpl func(tag *[TagSize]byte, msg []byte, key *[32]byte)) {
	var tag [16]byte
	for i, v := range testData {
		in := v.Input()
		if unaligned {
			in = unalignBytes(in)
		}
		key := v.Key()
		sumImpl(&tag, in, &key)
		if tag != v.Tag() {
			t.Errorf("%d: expected %x, got %x", i, v.Tag(), tag[:])
		}
	}
}

func TestBurnin(t *testing.T) {
	// This test can be used to sanity-check significant changes. It can
	// take about many minutes to run, even on fast machines. It's disabled
	// by default.
	if !*stressFlag {
		t.Skip("skipping without -stress")
	}

	var key [32]byte
	var input [25]byte
	var output [16]byte

	for i := range key {
		key[i] = 1
	}
	for i := range input {
		input[i] = 2
	}

	for i := uint64(0); i < 1e10; i++ {
		Sum(&output, input[:], &key)
		copy(key[0:], output[:])
		copy(key[16:], output[:])
		copy(input[:], output[:])
		copy(input[16:], output[:])
	}

	const expected = "5e3b866aea0b636d240c83c428f84bfa"
	if got := hex.EncodeToString(output[:]); got != expected {
		t.Errorf("expected %s, got %s", expected, got)
	}
}

func TestSum(t *testing.T)                 { testSum(t, false, Sum) }
func TestSumUnaligned(t *testing.T)        { testSum(t, true, Sum) }
func TestSumGeneric(t *testing.T)          { testSum(t, false, sumGeneric) }
func TestSumGenericUnaligned(t *testing.T) { testSum(t, true, sumGeneric) }

func benchmark(b *testing.B, size int, unaligned bool) {
	var out [16]byte
	var key [32]byte
	in := make([]byte, size)
	if unaligned {
		in = unalignBytes(in)
	}
	b.SetBytes(int64(len(in)))
	b.ResetTimer()
	for i := 0; i < b.N; i++ {
		Sum(&out, in, &key)
	}
}

func Benchmark64(b *testing.B)          { benchmark(b, 64, false) }
func Benchmark1K(b *testing.B)          { benchmark(b, 1024, false) }
func Benchmark64Unaligned(b *testing.B) { benchmark(b, 64, true) }
func Benchmark1KUnaligned(b *testing.B) { benchmark(b, 1024, true) }
func Benchmark2M(b *testing.B)          { benchmark(b, 2097152, true) }

func unalignBytes(in []byte) []byte {
	out := make([]byte, len(in)+1)
	if uintptr(unsafe.Pointer(&out[0]))&(unsafe.Alignof(uint32(0))-1) == 0 {
		out = out[1:]
	} else {
		out = out[:len(in)]
	}
	copy(out, in)
	return out
}