diff --git a/plugins/ssh-agent/ssh-agent.plugin.zsh b/plugins/ssh-agent/ssh-agent.plugin.zsh
index becd5ea17..acf56cc35 100644
--- a/plugins/ssh-agent/ssh-agent.plugin.zsh
+++ b/plugins/ssh-agent/ssh-agent.plugin.zsh
@@ -44,8 +44,8 @@ function _add_identities() {
   if [[ ${#identities[@]} -eq 0 ]]; then
     # Iterate over files in .ssh folder.
     for file in "$HOME/.ssh"/*; do
-      # Check if file is a regular file and starts with "-----BEGIN OPENSSH PRIVATE KEY-----".
-      if [[ -f "$file" && $(command head -n 1 "$file") =~ ^-----BEGIN\ OPENSSH\ PRIVATE\ KEY----- ]]; then
+      # Check if file is a valid private key using file magic.
+      if [[ -f "$file" && $(file -b "$file") == *"private key"* ]]; then
         # Add filename (without path) to identities array.
         identities+=("${file##*/}")
       fi