1 files changed, 52 insertions, 0 deletions
diff --git a/static/decrypt-aes-gcm.go b/static/decrypt-aes-gcm.go
new file mode 100644
index 0000000..bab07b5
--- /dev/null
+++ b/static/decrypt-aes-gcm.go
@@ -0,0 +1,52 @@
+package main
+
+import (
+	"crypto/aes"
+	"crypto/cipher"
+	"encoding/hex"
+	"errors"
+	"io/ioutil"
+	"os"
+)
+
+func main() {
+	err := inner()
+	if err != nil {
+		panic(err.Error())
+	}
+}
+
+func inner() error {
+	if len(os.Args) < 3 {
+		return errors.New("usage: ./decrypt-aes-gcm <key> <nonce> < input-file > output-file")
+	}
+	key, err := hex.DecodeString(os.Args[1])
+	if err != nil {
+		return err
+	}
+	nonce, err := hex.DecodeString(os.Args[2])
+	if err != nil {
+		return err
+	}
+	ciphertext, err := ioutil.ReadAll(os.Stdin)
+	if err != nil {
+		return err
+	}
+	block, err := aes.NewCipher(key)
+	if err != nil {
+		return err
+	}
+	aesgcm, err := cipher.NewGCM(block)
+	if err != nil {
+		return err
+	}
+	plaintext, err := aesgcm.Open(nil, nonce, ciphertext, nil)
+	if err != nil {
+		return err
+	}
+	_, err = os.Stdout.Write(plaintext)
+	if err != nil {
+		return err
+	}
+	return nil
+}