Merge pull request #23271 from owncloud/backport-23192

[stable9] Backport 23192

apps/encryption/lib/crypto/crypt.php

@@ -266,6 +266,13 @@ class Crypt {
 			$cipher = self::DEFAULT_CIPHER;
 		}
 
+		// Workaround for OpenSSL 0.9.8. Fallback to an old cipher that should work.
+		if(OPENSSL_VERSION_NUMBER < 0x1000101f) {
+			if($cipher === 'AES-256-CTR' || $cipher === 'AES-128-CTR') {
+				$cipher = self::LEGACY_CIPHER;
+			}
+		}
+
 		return $cipher;
 	}