### Ejemplo Go de implementación de generación de firmas: 

```go
package main
import (
	"crypto/sha1"
    "crypto/subtle"
	"encoding/hex"
	"strings"
)
type XsollaWebhookSignature struct{}
func (x *XsollaWebhookSignature) ComputeSha1(jsonBody, secretKey string) string {
	// Concatenation of the JSON from the request body and the project's secret key
	dataToSign := jsonBody + secretKey
	// Create SHA1 hash
	h := sha1.New()
	h.Write([]byte(dataToSign))
	signature := h.Sum(nil)
	// Convert to lowercase hexadecimal string
	return strings.ToLower(hex.EncodeToString(signature))
}
func (x *XsollaWebhookSignature) VerifySignature(jsonBody, secretKey, receivedSignature string) bool {
	computedSignature := x.ComputeSha1(jsonBody, secretKey)
	receivedSignatureLower := strings.ToLower(receivedSignature)
	// Use constant time comparison to prevent timing attacks
	return subtle.ConstantTimeCompare([]byte(computedSignature), []byte(receivedSignatureLower)) == 1
}
```