hmacSha256 function
Compute HMAC-SHA256 of text with key.
Implementation
Future<String> hmacSha256(String key, String text) async {
final proc = await Process.run('sh', [
'-c',
'printf "%s" "\$1" | openssl dgst -sha256 -hmac "\$2" -hex',
'--',
text,
key,
], stdoutEncoding: utf8);
final output = (proc.stdout as String).trim();
final idx = output.indexOf('= ');
return idx >= 0 ? output.substring(idx + 2).trim() : output;
}