PTDigitalSignatureField

Constructs a PDF::DigitalSignatureField from a PDF::Field.

Returns whether the digital signature field has been cryptographically signed. Checks whether there is a digital signature dictionary in the field and whether it has a Contents entry. Must be called before using various digital signature dictionary-related functions. Does not check validity - will return true even if a valid hash has not yet been generated (which will be the case after [Certify/Sign]OnNextSave[WithCustomHandler] has been called on the signature but even before Save is called on the document).

Returns the SubFilter type of the digital signature. Specification says that one must check the SubFilter before using various getters. Must call HasCryptographicSignature first and use it to check whether the signature is signed.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Returns the name of the signer of the signature from the digital signature dictionary. Must call HasCryptographicSignature first and use it to check whether the signature is signed.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Returns the “M” entry from the digital signature dictionary, which represents the signing date/time. Must call HasCryptographicSignature first and use it to check whether the signature is signed.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Returns the Location of the signature from the digital signature dictionary. Must call HasCryptographicSignature first and use it to check whether the signature is signed.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Returns the Reason for the signature from the digital signature dictionary. Must call HasCryptographicSignature first and use it to check whether the signature is signed.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Returns the contact information of the signer from the digital signature dictionary. Must call HasCryptographicSignature first and use it to check whether the signature is signed.

Gets a certificate in the certificate chain (Cert entry) of the digital signature dictionary by index. Throws if Cert is not Array or String, throws if index is out of range and Cert is Array, throws if index is > 1 and Cert is string, otherwise retrieves the certificate. Only to be used for old-style adbe.x509.rsa_sha1 signatures; for other signatures, use CMS getter functions instead.

Gets number of certificates in certificate chain (Cert entry of digital signature dictionary). Must call HasCryptographicSignature first and use it to check whether the signature is signed. Only to be used for old-style adbe.x509.rsa_sha1 signatures; for other signatures, use CMS getter functions instead.

Returns whether the field has a visible appearance. Can be called without checking HasCryptographicSignature first, since it operates on the surrounding Field dictionary, not the “V” entry (i.e. digital signature dictionary). Performs the zero-width+height check, the Hidden bit check, and the NoView bit check as described by the PDF 2.0 specification, section 12.7.5.5 “Signature fields”.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Sets the ContactInfo entry in the digital signature dictionary. Must create a digital signature dictionary first using [Certify/Sign]OnNextSave[WithCustomHandler]. If this function is called on a digital signature field that has already been cryptographically signed with a valid hash, the hash will no longer be valid, so do not call Save (to sign/create the hash) until after you call this function, if you need to call this function in the first place. Essentially, call this function after [Certify/Sign]OnNextSave[WithCustomHandler] and before Save.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Sets the Location entry in the digital signature dictionary. Must create a digital signature dictionary first using [Certify/Sign]OnNextSave[WithCustomHandler]. If this function is called on a digital signature field that has already been cryptographically signed with a valid hash, the hash will no longer be valid, so do not call Save (to sign/create the hash) until after you call this function, if you need to call this function in the first place. Essentially, call this function after [Certify/Sign]OnNextSave[WithCustomHandler] and before Save.

Should not be called when SubFilter is ETSI.RFC3161 (i.e. on a DocTimeStamp). Sets the Reason entry in the digital signature dictionary. Must create a digital signature dictionary first using [Certify/Sign]OnNextSave[WithCustomHandler]. If this function is called on a digital signature field that has already been cryptographically signed with a valid hash, the hash will no longer be valid, so do not call Save (to sign/create the hash) until after you call this function, if you need to call this function in the first place. Essentially, call this function after [Certify/Sign]OnNextSave[WithCustomHandler] and before Save.

Tentatively sets which fields are to be locked by this digital signature upon signing. It is not necessary to call HasCryptographicSignature before using this function. Throws if non-empty array of field names is passed along with FieldPermissions Action == e_lock_all.

Sets the document locking permission level for this digital signature field. Call only on unsigned signatures, otherwise a valid hash will be invalidated.

Must be called to prepare a signature for signing, which is done afterwards by calling Save. Cannot sign two signatures during one save (throws). Default document permission level is e_annotating_formfilling_signing_allowed. Throws if signature field already has a digital signature dictionary.

Must be called to prepare a signature for signing, which is done afterwards by calling Save. Cannot sign two signatures during one save (throws). Default document permission level is e_annotating_formfilling_signing_allowed. Throws if signature field already has a digital signature dictionary.

Must be called to prepare a signature for certification, which is done afterwards by calling Save. Throws if document already certified. Default document permission level is e_annotating_formfilling_signing_allowed. Throws if signature field already has a digital signature dictionary.

Must be called to prepare a signature for certification, which is done afterwards by calling Save. Throws if document already certified. Default document permission level is e_annotating_formfilling_signing_allowed. Throws if signature field already has a digital signature dictionary.

Retrieves the SDF Obj of the digital signature field.

Returns whether this digital signature field is locked against modifications by any digital signatures. Can be called when this field is unsigned.

Returns the fully-qualified names of all fields locked by this signature using the field permissions feature. Retrieves from the digital signature dictionary if the form field HasCryptographicSignature. Otherwise, retrieves from the Lock entry of the digital signature form field. Result is invalidated by any field additions or removals. Does not take document permissions restrictions into account.

If HasCryptographicSignature, returns most restrictive permissions found in any reference entries in this digital signature. Returns Lock-resident (i.e. tentative) permissions otherwise. Throws if invalid permission value is found.

Clears cryptographic signature, if present. Otherwise, does nothing. Do not need to call HasCryptographicSignature before calling this. After clearing, other signatures should still pass validation if saving after clearing was done incrementally. Clears the appearance as well.

Verifies this cryptographic digital signature in the manner specified by the VerificationOptions.

Returns whether or not this signature is a certification.

Returns the signing certificate. Must only be called on signed adbe.pkcs7.detached or ETSI.CAdES.detached signatures.

Retrieves the ranges of byte indices within the document over which this signature is intended to apply/be verifiable.

Retrieves all constructible certificate paths from an adbe.pkcs7.detached or ETSI.CAdES.detached digital signature.

• The signer will always be returned if the signature is CMS-based and not corrupt. Must only be called on
• signed adbe.pkcs7.detached signatures. The order of the certificates in each of the paths returned is as follows:
• the signer will be first, and issuers come after it in order of the issuer of the previous certificate.
• The default behaviour is to return a sub-path for each marginal issuer in a max-length path. *
• - returns: a container of X509Certificate objects *
• - note: This function does not verify the paths. It merely extracts certificates and constructs paths.
• This function only works when the build has support for verification-related APIs.

Given a successful verification result that required online information to verify trust (trust verification must have been enabled and successful during the verification), embeds data into the PDF document that allows the signature to be verified offline. (This is accomplished using DSS and VRI dictionaries.) When this operation is successfully completed, one of the two components of secure long term validation (LTV) will be in place. The other necessary component of secure long term validation is to make sure to timestamp the document appropriately while the signature is still verifiable to maintain a chain of unexpired secure timestamps attesting to the integrity of the document. The verifiability of the signature should thereafter be maintainable in such a fashion despite any possible certificate expiry, algorithm compromise, or key compromise that would have otherwise rendered it invalid if it were to be verified using a time in the future rather than a securely-signed timestamp-derived time nearer the time of signing (at which which the signature was verifiable without extra data). This function, if given a good verification result, is also capable of making timestamp (DocTimeStamp ETSI.RFC3161) signatures LTV-enabled, which is necessary to do first when you intend to add another timestamp around an already-timestamped document to extend or enhance its verifiability (as described above), as per the PDF 2.0 and ETSI TS 102 778-4 (PAdES Level 4) specifications.

Must be called to prepare a secure PDF-embedded timestamp signature (RFC 3161

• DocTimeStamp) for signing, which is done afterwards by calling Save on the
• document with an e_incremental flag. Throws if document is locked by other
• signatures, if signature is already signed, or if another signature has already
• been prepared for signing on the next save (because only one signing operation
• can be done per incremental save). Default document permission level is
• e_annotating_formfilling_signing_allowed. *
• - parameter: in_timestamping_config – Configuration options to store for timestamping.
• These will include various items related to contacting a timestamping authority.
• Incorrect configuration will result in document Save throwing an exception.
• The usability of a combination of a TimestampingConfiguration and VerificationOptions
• can be checked ahead of time to prevent exceptions by calling TestConfiguration on
• TimestampingConfiguration and passing VerificationOptions. *
• - parameter: in_timestamp_response_verification_options – Options for the timestamp
• response verification step (which is required by RFC 3161 to be done as part of
• timestamping). These response verification options should include the root certificate
• of the timestamp authority, so that the trust status of the timestamp signature
• can be verified. The options that should be passed are the same ones that one expects
• the timestamp to be verifiable with in the future (once it is embedded in the document),
• except the response verification requires online revocation information whereas
• the later verification may not (depending on whether LTV offline verification
• information for the timestamp signature gets embedded into the document by that
• time). The timestamp response verification step makes sure that (a) the
• timestamp response has a success status, which is the only time that this is
• verified in the entire workflow, which prevents embedding an unsuccessful
• response; (b) that it digests the document correctly and is otherwise generally
• verifiable; and © that the nonce is correct (which is the only time that this
• is verifiable in the entire workflow) to prevent replay attacks (if it was not
• requested in the TimestampingConfiguration that the nonce mechanism should be
• disabled). *
• - note: A failure in timestamp response verification will result in document Save
• throwing an exception. It is recommended to use TimestampingConfiguration.TestConfiguration
• with the VerificationOptions ahead of time to avoid this. *

Contacts a remote timestamp authority over network, sends CMS digest, receives and verifies timestamp token, combines the timestamp token and the data of an existing CMS-type (adbe.pkcs7.detached or ETSI.CAdES.detached subfilter) main document signature, and then returns that data to the user. At least one signing time, whether “M” (see SetSigDictTimeOfSigning) or a secure embedded timestamp, is required to be added in order to create a PAdES signature.

Sets the requested SubFilter value (which identifies a signature type) as the only one to use during future signing, overwriting all such previous settings. It is not necessary to call HasCryptographicSignature before calling this function. For example, this function can be used to switch to PAdES signing mode.

Calculates the digest of the relevant bytes of the document for this signature field, in order to allow

• the caller to perform custom signing/processing. Signature field must first be prepared using one of the
• non-sign overloads (CreateSigDictForCustomSigning/Certification), and then the document must be saved; after that, this function can be called.
• The ByteRanges that the most recent save has entered into the signature dictionary within this signature field
• will be used to calculate the digest. *
• - parameter: in_digest_algorithm_type – the enumerated type of digest algorithm to use for the calculation. The default is SHA-256.
• - returns: an array of bytes containing the digest value

Sets the preferred digest algorithm to use when signing this field. This is done by setting DigestMethod

• in the Seed Value dictionary. This function can be called before a signature field is even prepared for signing. *
• - parameter: in_digest_algorithm_type – the digest algorithm to use
• - parameter: in_make_mandatory – whether to tell signing software to give up if the preferred algorithm is unsupported. Default value for this parameter is true.

Prepares the field for certification without actually performing certification.

• Useful for custom signing workflows. It is not necessary to call HasCryptographicSignature
• before calling this function. *
• - parameter: in_filter_name the Filter name to use, representing the name of the signature handler that will be used to sign and verify the signature (e.g. Adobe.PPKLite)
• - parameter: in_subfilter_type the SubFilter name to use, representing an interoperable signature type identifier for third-party verification (e.g. adbe.pkcs7.detached, ETSI.CAdES.detached, etc.)
• - parameter: in_contents_size_to_reserve The size of the empty Contents entry to create. For security reasons, set the contents size to a value greater than but as close as possible to the size you expect your final signature to be.

Prepares the field for approval signing without actually performing signing.

• Useful for custom signing workflows. It is not necessary to call HasCryptographicSignature
• before calling this function. *
• - parameter: in_filter_name the Filter name to use, representing the name of the signature handler that will be used to sign and verify the signature (e.g. Adobe.PPKLite)
• - parameter: in_subfilter_type the SubFilter name to use, representing an interoperable signature type identifier for third-party verification (e.g. adbe.pkcs7.detached, ETSI.CAdES.detached, etc.)
• - parameter: in_contents_size_to_reserve The size of the empty Contents entry to create. For security reasons, set the contents size to a value greater than but as close as possible to the size you expect your final signature to be.

Adds the “M” key and value, representing the PDF-time-of-signing (not to be confused with

• embedded timestamps, DocTimeStamps, or CMS signing time), to the digital signature dictionary.
• The digital signature field must have been prepared for signing first. This function should
• only be used if no secure embedded timestamping support is available from your signing provider.
• Useful for custom signing workflows, where signing time is not set automatically by the Apryse SDK,
• unlike in the usual standard handler signing workflow. A secure embedded timestamp can also be added
• later and should override this “M” date entry when the signature is read by signature-verifying PDF processor applications.
• At least one signing time, whether “M” or a secure embedded timestamp (see GenerateContentsWithEmbeddedTimestamp),
• is required to be added in order to create a PAdES signature. *
• - parameter: in_date the PDF Date datetime value to set

Returns a CMS detached signature incorporating a digest that is provided using the provided PKCS #12 key file (.pfx). This function is part of the custom signing API, but cannot be used for workflows where the key is not in PFX format or when the signature comes from a source that cannot generate CMS signatures (e.g. Hardware Security Modules (HSM) devices, cloud signing services). In such cases, the low-level parts of the custom signing API should be used instead of this function (e.g. GenerateESSSigningCertPAdESAttribute, GenerateCMSSignedAttributes, GenerateCMSSignature). This function is a shortcut for situations in which use of more low-level custom signing functions is unnecessary. Therefore, this function will generate necessary CMS components, such as signedAttrs, internally.

Returns a CMS detached signature incorporating a digest that is provided using the provided PKCS #12 key buffer (.pfx). This function is part of the custom signing API, but cannot be used for workflows where the key is not in PFX format or when the signature comes from a source that cannot generate CMS signatures (e.g. Hardware Security Modules (HSM) devices, cloud signing services). In such cases, the low-level parts of the custom signing API should be used instead of this function (e.g. GenerateESSSigningCertPAdESAttribute, GenerateCMSSignedAttributes, GenerateCMSSignature). This function is a shortcut for situations in which use of more low-level custom signing functions is unnecessary. Therefore, this function will generate necessary CMS components, such as signedAttrs, internally.

Low-level optional function belonging to custom-signing APIs allowing creation of PAdES signatures with key elsewhere, allowing CMS to be generated automatically later. Represents one the components of the functionality of SignDigest which are not key-related. Creates the necessary attribute for a PAdES signature (ETSI.CAdES.detached subfilter type). The result of this function can be passed as a contiguous part of the custom attributes buffer parameter of GenerateCMSSignedAttributes. At least one signing time, whether “M” (see SetSigDictTimeOfSigning) or a secure embedded timestamp (see GenerateContentsWithEmbeddedTimestamp), is also required to be added in order to create a PAdES signature.

The result will be either the BER-serialized bytes of an ESS_signing_cert or ESS_signing_cert_V2 CMS Attribute (an ASN.1 SEQUENCE containing the correct OID and ESSCertID or ESSCertIDv2), as is appropriate, depending on what digest algorithm type is provided (see RFC 5035).

Low-level function belonging to custom-signing APIs. Creates the signedAttributes component of Cryptographic Message Syntax (CMS). The result of this function can then be encrypted by a remote private key (cloud service, Hardware Security Module (HSM) device, etc.), using some external API that returns the bytes of a not-already-CMS-embedded signature value (e.g. RSA PKCS #1 v1.5 format). Following that, CMS generation can be performed using GenerateCMSSignature, after which the resulting signature can be inserted into a resulting signed version of the PDF document using the PDFDoc function SaveCustomSignature.

Low-level function belonging to custom-signing APIs. Using low-level inputs that permit incorporation of remote key usage (cloud keystore, Hardware Security Module (HSM) device, etc.), generates bytes representing a Cryptographic Message Syntax (CMS)-format signature encoded in DER. The resulting data can be passed to SaveCustomSignature.