status-go/wakuv2/common/helpers.go

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package common
import (
"crypto/ecdsa"
crand "crypto/rand"
"errors"
"fmt"
mrand "math/rand"
"github.com/ethereum/go-ethereum/common"
)
// IsPubKeyEqual checks that two public keys are equal
func IsPubKeyEqual(a, b *ecdsa.PublicKey) bool {
if !ValidatePublicKey(a) {
return false
} else if !ValidatePublicKey(b) {
return false
}
// the curve is always the same, just compare the points
return a.X.Cmp(b.X) == 0 && a.Y.Cmp(b.Y) == 0
}
// ValidatePublicKey checks the format of the given public key.
func ValidatePublicKey(k *ecdsa.PublicKey) bool {
return k != nil && k.X != nil && k.Y != nil && k.X.Sign() != 0 && k.Y.Sign() != 0
}
// BytesToUintLittleEndian converts the slice to 64-bit unsigned integer.
func BytesToUintLittleEndian(b []byte) (res uint64) {
mul := uint64(1)
for i := 0; i < len(b); i++ {
res += uint64(b[i]) * mul
mul *= 256
}
return res
}
// BytesToUintBigEndian converts the slice to 64-bit unsigned integer.
func BytesToUintBigEndian(b []byte) (res uint64) {
for i := 0; i < len(b); i++ {
res *= 256
res += uint64(b[i])
}
return res
}
// ContainsOnlyZeros checks if the data contain only zeros.
func ContainsOnlyZeros(data []byte) bool {
for _, b := range data {
if b != 0 {
return false
}
}
return true
}
// GenerateSecureRandomData generates random data where extra security is required.
// The purpose of this function is to prevent some bugs in software or in hardware
// from delivering not-very-random data. This is especially useful for AES nonce,
// where true randomness does not really matter, but it is very important to have
// a unique nonce for every message.
func GenerateSecureRandomData(length int) ([]byte, error) {
x := make([]byte, length)
y := make([]byte, length)
res := make([]byte, length)
_, err := crand.Read(x)
if err != nil {
return nil, err
} else if !ValidateDataIntegrity(x, length) {
return nil, errors.New("crypto/rand failed to generate secure random data")
}
_, err = mrand.Read(y) // nolint: gosec
if err != nil {
return nil, err
} else if !ValidateDataIntegrity(y, length) {
return nil, errors.New("math/rand failed to generate secure random data")
}
for i := 0; i < length; i++ {
res[i] = x[i] ^ y[i]
}
if !ValidateDataIntegrity(res, length) {
return nil, errors.New("failed to generate secure random data")
}
return res, nil
}
// GenerateRandomID generates a random string, which is then returned to be used as a key id
func GenerateRandomID() (id string, err error) {
buf, err := GenerateSecureRandomData(KeyIDSize)
if err != nil {
return "", err
}
if !ValidateDataIntegrity(buf, KeyIDSize) {
return "", fmt.Errorf("error in generateRandomID: crypto/rand failed to generate random data")
}
id = common.Bytes2Hex(buf)
return id, err
}
// ValidateDataIntegrity returns false if the data have the wrong or contains all zeros,
// which is the simplest and the most common bug.
func ValidateDataIntegrity(k []byte, expectedSize int) bool {
if len(k) != expectedSize {
return false
}
if expectedSize > 3 && ContainsOnlyZeros(k) {
return false
}
return true
}