mirror of
https://gitlab.com/pulsechaincom/prysm-pulse.git
synced 2024-12-23 11:57:18 +00:00
b381ad49b5
* pin gosec * edit * go back to master * justifications * Update crypto/bls/blst/signature.go * proper format * gosec
87 lines
3.5 KiB
Go
87 lines
3.5 KiB
Go
/*
|
|
Package rand defines methods of obtaining random number generators.
|
|
|
|
One is expected to use randomness from this package only, without introducing any other packages.
|
|
This limits the scope of code that needs to be hardened.
|
|
|
|
There are two modes, one for deterministic and another non-deterministic randomness:
|
|
1. If deterministic pseudo-random generator is enough, use:
|
|
|
|
import "github.com/prysmaticlabs/prysm/crypto/rand"
|
|
randGen := rand.NewDeterministicGenerator()
|
|
randGen.Intn(32) // or any other func defined in math.rand API
|
|
|
|
In this mode, only seed is generated using cryptographically secure source (crypto/rand). So,
|
|
once seed is obtained, and generator is seeded, the next generations are deterministic, thus fast.
|
|
However given that we only seed this 63 bits from crypto/rand and use math/rand to generate the outputs,
|
|
this method is not cryptographically secure. This is directly stated in the math/rand package,
|
|
https://github.com/golang/go/blob/release-branch.go1.17/src/math/rand/rand.go#L15. For any security
|
|
sensitive work this particular generator is NOT to be used.
|
|
|
|
2. For cryptographically secure non-deterministic mode (CSPRNG), use:
|
|
|
|
import "github.com/prysmaticlabs/prysm/crypto/rand"
|
|
randGen := rand.NewGenerator()
|
|
randGen.Intn(32) // or any other func defined in math.rand API
|
|
|
|
Again, any of the functions from `math/rand` can be used, however, they all use custom source
|
|
of randomness (crypto/rand), on every step. This makes randomness non-deterministic. However,
|
|
you take a performance hit -- as it is an order of magnitude slower.
|
|
*/
|
|
package rand
|
|
|
|
import (
|
|
"crypto/rand"
|
|
"encoding/binary"
|
|
mrand "math/rand"
|
|
"sync"
|
|
)
|
|
|
|
type source struct{}
|
|
|
|
var lock sync.RWMutex
|
|
var _ mrand.Source64 = (*source)(nil) // #nosec G404 -- This ensures we meet the interface
|
|
|
|
// Seed does nothing when crypto/rand is used as source.
|
|
func (_ *source) Seed(_ int64) {}
|
|
|
|
// Int63 returns uniformly-distributed random (as in CSPRNG) int64 value within [0, 1<<63) range.
|
|
// Panics if random generator reader cannot return data.
|
|
func (s *source) Int63() int64 {
|
|
return int64(s.Uint64() & ^uint64(1<<63))
|
|
}
|
|
|
|
// Uint64 returns uniformly-distributed random (as in CSPRNG) uint64 value within [0, 1<<64) range.
|
|
// Panics if random generator reader cannot return data.
|
|
func (_ *source) Uint64() (val uint64) {
|
|
lock.RLock()
|
|
defer lock.RUnlock()
|
|
if err := binary.Read(rand.Reader, binary.BigEndian, &val); err != nil {
|
|
panic(err)
|
|
}
|
|
return
|
|
}
|
|
|
|
// Rand is alias for underlying random generator.
|
|
type Rand = mrand.Rand // #nosec G404
|
|
|
|
// NewGenerator returns a new generator that uses random values from crypto/rand as a source
|
|
// (cryptographically secure random number generator).
|
|
// Panics if crypto/rand input cannot be read.
|
|
// Use it for everything where crypto secure non-deterministic randomness is required. Performance
|
|
// takes a hit, so use sparingly.
|
|
func NewGenerator() *Rand {
|
|
return mrand.New(&source{}) // #nosec G404 -- excluded
|
|
}
|
|
|
|
// NewDeterministicGenerator returns a random generator which is only seeded with crypto/rand,
|
|
// but is deterministic otherwise (given seed, produces given results, deterministically).
|
|
// Panics if crypto/rand input cannot be read.
|
|
// Use this method for performance, where deterministic pseudo-random behaviour is enough.
|
|
// Otherwise, rely on NewGenerator(). This method is not cryptographically secure as outputs
|
|
// can be potentially predicted even without knowledge of the underlying seed.
|
|
func NewDeterministicGenerator() *Rand {
|
|
randGen := NewGenerator()
|
|
return mrand.New(mrand.NewSource(randGen.Int63())) // #nosec G404 -- excluded
|
|
}
|