1 files changed, 27 insertions, 0 deletions
diff --git a/verify/core/crypt.go b/verify/core/crypt.go
new file mode 100644
index 0000000..067a0b3
--- /dev/null
+++ b/verify/core/crypt.go
@@ -0,0 +1,27 @@
+package core
+
+import (
+	"bytes"
+	"crypto/sha1"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// calculateStringHash calculates the sha1 checksum of a given string a.
+func calculateStringHash(a string) (string, error) {
+	hash := sha1.New()
+	hash.Write([]byte(a))
+	hashInBytes := hash.Sum(nil)[:20]
+	return strings.TrimSpace(fmt.Sprintf("%x", hashInBytes)), nil
+}
+
+// CalculateBlockHash calculates the sha1 checksum of a given byte slice b.
+func CalculateBlockHash(b []byte) (string, error) {
+	hash := sha1.New()
+	if _, err := io.Copy(hash, bytes.NewReader(b)); err != nil {
+		return "", err
+	}
+	hashInBytes := hash.Sum(nil)[:20]
+	return strings.TrimSpace(fmt.Sprintf("%x", hashInBytes)), nil
+}