#
  # NOTE: This procedure returns non-zero if the specified string value
  #       looks like a Harpy (script) certificate.  The value argument
  #       is the string to check.
  #
  # <public>
  proc isHarpyCertificate { value } {
    set length [string length $value]

    if {$length == 0 || ([string first [string trim {
      <?xml version="1.0" encoding="utf-8"?>
    }] $value] == 0 && [string first [string trim {
      <Certificate xmlns="https://eagle.to/2011/harpy"
    }] $value] != -1)} then {
      return true
    } else {
      return false
    }
  }

  #
  # NOTE: This procedure returns non-zero if the specified string value
  #       looks like an OpenPGP signature.  The value argument is the
  #       string to check.  The value 29 used within this procedure is
  #       the length of the literal string "-----END PGP SIGNATURE-----"
  #       followed by a carriage-return / line-feed pair, which means
  #       the value must be in DOS format.
  #
  # <public>
  proc isPgpSignature { value } {
    set length [string length $value]

    if {$length == 0 || ([string first [string trim {
      -----BEGIN PGP SIGNATURE-----
    }] $value] == 0 && [string first [string trim {
      -----END PGP SIGNATURE-----
    }] $value] == ($length - 29))} then {
      return true
    } else {
      return false
    }
  }

  #