Signature

Emits the /Sig value dictionary (the object referenced by a signature field's /V): the fixed skeleton, the /SubFilter, and the /ByteRange and /Contents placeholders that the host rewrites while signin

Table of contents

Namespace: Com\Tecnick\Pdf\Sign\Output

final class Signature

Source: src/Output/Signature.php:45

Emits the /Sig value dictionary (the object referenced by a signature field’s /V): the fixed skeleton, the /SubFilter, and the /ByteRange and /Contents placeholders that the host rewrites while signing, plus the optional Name/Location/Reason/ContactInfo strings.

The /Reference (DocMDP or UR3 transform) and the /M date token are supplied by the caller as ready fragments, their content and formatting depending on host state (certification level, user rights, timezone, encryption). String encoding (escaping, UTF-16, encryption) of the info values is delegated to an injected encoder.

Constants

BYTE_RANGE_PLACEHOLDER

ByteRange placeholder rewritten by the host once the byte offsets are known.

public const BYTE_RANGE_PLACEHOLDER = '/ByteRange[0 ********** ********** **********]'

Source: src/Output/Signature.php:50

DEFAULT_CONTENTS_LENGTH

Default number of hex zero placeholder characters reserved for /Contents.

public const DEFAULT_CONTENTS_LENGTH = 11742

Source: src/Output/Signature.php:55

MAX_CONTENTS_LENGTH

Largest /Contents placeholder this emitter reserves, in hex characters.

The window holds one CMS signature or one RFC 3161 token, so a megabyte of hex is far beyond what either needs. Past it str_repeat() would exhaust memory rather than throw.

public const MAX_CONTENTS_LENGTH = 1048576

Source: src/Output/Signature.php:64

Methods

objectHead()

Emit the head of a signature value object, up to and including /Contents.

ISO 32000-2 section 12.8.5 gives a /Sig and a /DocTimeStamp the same shape: the Adobe.PPKLite filter, the ByteRange placeholder the host rewrites once it knows the offsets, and a /Contents window reserved as hex zeros. Emitted here for both.

public static objectHead(
    int $objectId,
    string $type,
    string $subFilter,
    int $contentsLength,
    string $label
): string

Parameters:

  • $objectId (int): Object number for the value object.
  • $type (string): /Type name, without the leading solidus.
  • $subFilter (string): /SubFilter name, without the leading solidus.
  • $contentsLength (int): Placeholder length reserved for the signature, in hex digits; must be even and positive.
  • $label (string): Name of the object, for the error message.

Returns: string

Throws:

  • Exception: If a name, the object number, or the placeholder length is invalid.

Source: src/Output/Signature.php:142

valueObject()

Emit the /Sig value object.

public valueObject(
    int $objectId,
    string $subFilter,
    string $reference,
    array<string,string> $info,
    string $dateValue,
    int $contentsLength = \self::DEFAULT_CONTENTS_LENGTH,
    callable|null $stringEncoder = null
): string

Parameters:

  • $objectId (int): Object number for the /Sig value object.
  • $subFilter (string): e.g. “ETSI.CAdES.detached” or “adbe.pkcs7.detached”.
  • $reference (string): Ready /Reference fragment (DocMDP or UR3 transform), leading space included, or ’’ for an approval signature.
  • $info (array<string,string>): Optional Name/Location/Reason/ContactInfo.
  • $dateValue (string): Ready (already encoded) PDF string token for /M, or ’’ to omit the entry.
  • $contentsLength (int): Placeholder length for /Contents, in hex digits; must be even and positive.
  • $stringEncoder (callable|null): fn(string $text, int $objectId): string returning a PDF string token.

Returns: string

Throws:

  • Exception: If the object number, the /SubFilter, an info value, or the placeholder length is invalid, or the string encoder returns a non-string value.

Source: src/Output/Signature.php:91