frostfs-api-go/service/sign.go

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package service
import (
"crypto/ecdsa"
crypto "github.com/nspcc-dev/neofs-crypto"
)
// Returns data from DataSignatureAccumulator for signature creation/verification.
//
// If passed DataSignatureAccumulator provides a SignedDataReader interface, data for signature is obtained
// using this interface for optimization. In this case, it is understood that reading into the slice D
// that the method DataForSignature returns does not change D.
func dataForSignature(src SignedDataSource) ([]byte, error) {
r, ok := src.(SignedDataReader)
if !ok {
return src.SignedData()
}
buf := bytesPool.Get().([]byte)
defer func() {
bytesPool.Put(buf)
}()
if size := r.SignedDataSize(); size <= cap(buf) {
buf = buf[:size]
} else {
buf = make([]byte, size)
}
n, err := r.ReadSignedData(buf)
if err != nil {
return nil, err
}
return buf[:n], nil
}
// DataSignature returns the signature of data obtained using the private key.
//
// If passed data container is nil, ErrNilSignedDataSource returns.
// If passed private key is nil, crypto.ErrEmptyPrivateKey returns.
// If the data container or the signature function returns an error, it is returned directly.
func DataSignature(src SignedDataSource, key *ecdsa.PrivateKey) ([]byte, error) {
if src == nil {
return nil, ErrNilSignedDataSource
} else if key == nil {
return nil, crypto.ErrEmptyPrivateKey
}
data, err := dataForSignature(src)
if err != nil {
return nil, err
}
return crypto.Sign(key, data)
}