verify-signature() #

boolean verify-signature(string signature, string data, string public_key [, string algorithm = "SHA256"])

The verify-signature() function verifies a given Base64-encoded signature for the given data using the given public_key (in PEM format, with or without boundaries). The optional parameter algorithm is the signing algorithm (the default is "SHA256", → supported algorithms). It returns true() if the signature could be verified, false() otherwise.

Example #

<flow>
  <eval out="$public_key">$metadata//*[@use = "signing"]//*[local-name() = "X509Certificate"]</eval>
  <template>
  {
    {{$data := 'my data' }}
    {{$signature := 'C+BxESu4KiMWj/pVkY4j29FDu …Bfv95ZZER7DYkGwUOw==' }}
    {{$signature_ok := verify-signature($signature, $data, $public_key) }}
    {{$signature_ok := verify-signature($signature, $data, $public_key, 'SHA256') }}

    {{$signature_NOT_ok := verify-signature($signature, 'different data', $public_key) }}
  }
  </template>
<flow>

See also #

• calc-signature()