updated deps; updated healthchecks.io integration

vendor/maunium.net/go/mautrix/crypto/pkcs7/pkcs7.go

@@ -0,0 +1,30 @@
+// Copyright (c) 2024 Sumner Evans
+//
+// This Source Code Form is subject to the terms of the Mozilla Public
+// License, v. 2.0. If a copy of the MPL was not distributed with this
+// file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+package pkcs7
+
+import "bytes"
+
+// Pad implements PKCS#7 padding as defined in [RFC2315]. It pads the plaintext
+// to the given blockSize in the range [1, 255]. This is normally used in
+// AES-CBC encryption.
+//
+// [RFC2315]: https://www.ietf.org/rfc/rfc2315.txt
+func Pad(plaintext []byte, blockSize int) []byte {
+	padding := blockSize - len(plaintext)%blockSize
+	return append(plaintext, bytes.Repeat([]byte{byte(padding)}, padding)...)
+}
+
+// Unpad implements PKCS#7 unpadding as defined in [RFC2315]. It unpads the
+// plaintext by reading the padding amount from the last byte of the plaintext.
+// This is normally used in AES-CBC decryption.
+//
+// [RFC2315]: https://www.ietf.org/rfc/rfc2315.txt
+func Unpad(plaintext []byte) []byte {
+	length := len(plaintext)
+	unpadding := int(plaintext[length-1])
+	return plaintext[:length-unpadding]
+}