Use this tab to define an optional signature handler for a document signature or a data signature. A signature handler is a software module that implements the public-key cryptography process and controls access to the encrypted document or data. Examples of signature handlers that support public-key encryption include Adobe.PPKLite, VeriSign.PPKVS, and Entrust.PPKEF.
Note:
Adobe.PPKLite (Adobe Default Security) is the only signature handler that is designed to analyze and process the information that you enter in the Signature Settings and Sign Data and Submit Settings dialog boxes. Third-party signature handlers may not process this information.
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Select a submit button, click the Submit tab in the Object palette, ensure that Sign Submission is selected, click Settings, and then click the Signature Handler tab.
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Select an email or HTTP submit button and, in the Object palette, ensure that Sign Submission is selected, click Settings, and then click the Signature Handler tab.
Forces Acrobat to use the signature handler (also known as a filter) that is specified in the Name list box to create the digital signature. If the signing party does not have the specified signature handler available on their computer, Acrobat will cancel the signing operation.
When deciding whether to require the signing party to use the specified signature handler (which they may or may not have available), it is helpful to understand what the signing party can and cannot do in Acrobat and Adobe Reader, depending on the cirsumstances.
Available to signing party
Acrobat orAdobe Reader attempts to use the default installed signing method, but allows the signing party to select any other installed signature handler.
Acrobat or Adobe Reader lets the signing party use only the signature handler specified in the Name list. The signing party cannot use any other signature handler.
Acrobat or Adobe Reader requires the signing party to use the signature handler specified in the Name list. The signing party cannot sign until they install the specified signature handler.
Acrobat or Adobe Reader requires the signing party to use the signature handler specified in the Name list.
Specifies the syntax of the contents of the encryption dictionary and allows inter operability between handlers. The valid subFilters for digital signatures that Acrobat recognize are adbe.x509.rsa_sha1, adbe.pkcs7.detached, and adbe.pkcs7.sha1.
Forces Acrobat or Adobe Reader to use one of the specified subFilters. The first name in the subFilter list that matches an encoding method supported by the signature handler is used as the encoding method for signing. If you specify a subFilter, and the flags property indicates that this entry is a required constraint, the first matching encoding is used when signing; otherwise, signing will not take place. If the flags property indicates that this is an optional constraint, the first matching encoding is used if it is available. If it is not available, the system default encoding is used.
When deciding whether to require the signing party to use the specified subFilter (which they may or may not have available), it is helpful to understand what the signing party can and cannot do in Acrobat and Adobe Reader, depending on the circumstances.
Note:
The Adobe.PPKLite signature handler analyzes and processes the subFilter information that you enter in the Signature Settings and the Sign Data and Submit Settings dialog boxes, not Adobe Acrobat. As a result, these four situations arise only if you select the Adobe.PPKLite signature handler. Third-party signature handlers may not process this information.
Available to signing party
The Adobe default security handler requires the signing party to use one of the subFilters specified in the subFilter list. If you do not specify a subFilter, the signing party can use another subFilter.
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
The Adobe default security handler lets the signing party use only one of the subFilters specified in the subFilter list. The signing party cannot use any other subFilter.
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
The Adobe default security handler requires the signing party to use one of the subFilters specified in the subFilter list. The signing party cannot sign until they install one of the specified subFilters.
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
The Adobe default security handler requires the signing party to use one of the subFilters specified in the subFilter list.
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
Specify the acceptable digest method element values. The valid string values are MD5, SHA1, SHA256, SHA384, SHA512, and RIPEMD160.
Forces Acrobat or Adobe Reader to use the specified digest method.
When deciding whether to require the signing party to use the digest method (which they may or may not have available), it is helpful to understand what the signing party can and cannot do in Acrobat and Adobe Reader, depending on the circumstances.
Note:
The Adobe.PPKLite signature handler analyzes and processes the digest method information that you enter in the Signature Settings and the Sign Data and Submit Settings dialog boxes, not Adobe Acrobat. As a result, these four situations arise only if you select the Adobe.PPKLite signature handler. Third-party signature handlers may not process this information.
Available to signing party
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
The Adobe default security handler requires the signing party to use one of the digest methods specified in the Digest Method list. The signing party cannot use another digest method.
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
The Adobe default security handler requires the signing party to use one of the digest methods specified in the Digest Method list.
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
The Adobe default security handler requires the signing party to use one of the digest methods specified in the Digest Method list.
If you specify a signature handler other than the Adobe default security handler it may or may not respect this setting.
See also 

Signature Handler tab (Signature Settings/Sign Data and Submit Settings dialog box)