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perl-net-saml2 / perl-XML-Sig

XML::Sig - A Perl toolkit to help sign and verify XML Digital Signatures.
https://metacpan.org/pod/XML::Sig
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dsa dsig ecdsa hmac hmac-signature perl ripemd160 rsa sha xml xmlsec

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NAME XML::Sig - XML::Sig - A toolkit to help sign and verify XML Digital Signatures

VERSION version 0.65

SYNOPSIS my $xml = '123'; my $signer = XML::Sig->new({ key => 'path/to/private.key', });

   # create a signature
   my $signed = $signer->sign($xml);
   print "Signed XML: $signed\n";

   # verify a signature
   $signer->verify($signed)
     or die "Signature Invalid.";
   print "Signature valid.\n";

DESCRIPTION This perl module provides two primary capabilities: given an XML string, create and insert digital signatures, or if one is already present in the string verify it -- all in accordance with the W3C standard governing XML signatures.

NAME XML::Sig - A toolkit to help sign and verify XML Digital Signatures.

PREREQUISITES

USAGE SUPPORTED ALGORITHMS & TRANSFORMS This module supports the following signature methods:

*   DSA

*   RSA

*   RSA encoded as x509

*   ECDSA

*   ECDSA encoded as x509

*   HMAC

This module supports the following canonicalization methods and
transforms:

*   Enveloped Signature

*   REC-xml-c14n-20010315#

*   REC-xml-c14n-20010315#WithComments

*   REC-xml-c14n11-20080502

*   REC-xml-c14n11-20080502#WithComments

*   xml-exc-c14n#

*   xml-exc-c14n#WithComments

OPTIONS Each of the following options are also accessors on the main XML::Sig object. TODO Not strictly correct rewrite

key The path to a file containing the contents of a private key. This
    option is used only when generating signatures.

cert
    The path to a file containing a PEM-formatted X509 certificate. This
    option is used only when generating signatures with the "x509"
    option. This certificate will be embedded in the signed document,
    and should match the private key used for the signature.

cert_text
    A string containing a PEM-formatted X509 certificate. This option is
    used only when generating signatures with the "x509" option. This
    certificate will be embedded in the signed document, and should
    match the private key used for the signature.

x509
    Takes a true (1) or false (0) value and indicates how you want the
    signature to be encoded. When true, the X509 certificate supplied
    will be encoded in the signature. Otherwise the native encoding
    format for RSA, DSA and ECDSA will be used.

sig_hash
    Passing sig_hash to new allows you to specify the SignatureMethod
    hashing algorithm used when signing the SignedInfo. RSA and ECDSA
    supports the hashes specified sha1, sha224, sha256, sha384 and
    sha512

    DSA supports only sha1 and sha256 (but you really should not sign
    anything with DSA anyway). This is over-ridden by the key's
    signature size which is related to the key size. 1024-bit keys
    require sha1, 2048-bit and 3072-bit keys require sha256.

digest_hash
    Passing digest_hash to new allows you to specify the DigestMethod
    hashing algorithm used when calculating the hash of the XML being
    signed. Supported hashes can be specified sha1, sha224, sha256,
    sha384, sha512, ripemd160

hmac_key
    Base64 encoded hmac_key

key_name
    The name of the key that should be referenced. In the case of xmlsec
    the --keys-file (ex. t/xmlsec-keys.xml) holds keys with a KeyName
    that is referenced by this name.

no_xml_declaration
    Some applications such as Net::SAML2 expect to sign a fragment of
    the full XML document so is this is true (1) it will not include the
    XML Declaration at the beginning of the signed XML. False (0) or
    undefined returns an XML document starting with the XML Declaration.

The following options act similar to "xmlsec --id-attr:ID
<node-namespace-uri>:<name>"

ns  A HashRef to namespaces you want to define to select the correct
    attribute ID on

id_attr
    The xpath string you want to sign your XML message on.

METHODS new(...) Constructor; see OPTIONS above.

sign($xml) When given a string of XML, it will return the same string with a signature generated from the key provided when the XML::Sig object was initialized.

This method will sign all elements in your XML with an ID (case
sensitive) attribute. Each element with an ID attribute will be the
basis for a seperate signature. It will correspond to the URI attribute
in the Reference element that will be contained by the signature. If no
ID attribute can be found on an element, the signature will not be
created.

The elements are signed in reverse order currently assuming (possibly
incorrectly) that the lower element in the tree may need to be signed
inclusive of its Signature because it is a child of the higher element.

Arguments: $xml: string XML string

Returns: string Signed XML

verify($xml) Returns true or false based upon whether the signature is valid or not.

When using XML::Sig exclusively to verify a signature, no key needs to
be specified during initialization given that the public key should be
transmitted with the signature.

XML::Sig checks all signature in the provided xml and will fail should
any signature pointing to an existing ID in the XML fail to verify.

Should there be a Signature included that does not point to an existing
node in the XML it is ignored and other Signaures are checked. If there
are no other Signatures it will return false.

Arguments: $xml: string XML string

Returns: string Signed XML

signer_cert() Following a successful verify with an X509 certificate, returns the signer's certificate as embedded in the XML document for verification against a CA certificate. The certificate is returned as a Crypt::OpenSSL::X509 object.

Arguments: none

Returns: Crypt::OpenSSL::X509: Certificate used to sign the XML

ABOUT DIGITAL SIGNATURES Just as one might want to send an email message that is cryptographically signed in order to give the recipient the means to independently verify who sent the email, one might also want to sign an XML document. This is especially true in the scenario where an XML document is received in an otherwise unauthenticated context, e.g. SAML.

However XML provides a challenge that email does not. In XML, two
documents can be byte-wise inequivalent, and semanticaly equivalent at
the same time. For example:

    <?xml version="1.0"?>
    <foo>
      <bar />
    </foo>

    And:

    <?xml version="1.0"?>
    <foo>
      <bar></bar>
    </foo>

Each of these document express the same thing, or in other words they
"mean" the same thing. However if you were to strictly sign the raw text
of these documents, they would each produce different signatures.

XML Signatures on the other hand will produce the same signature for
each of the documents above. Therefore an XML document can be written
and rewritten by different parties and still be able to have someone at
the end of the line verify a signature the document may contain.

There is a specially subscribed methodology for how this process should
be executed and involves transforming the XML into its canonical form so
a signature can be reliably inserted or extracted for verification. This
module implements that process.

EXAMPLE SIGNATURE Below is a sample XML signature to give you some sense of what they look like. First let's look at the original XML document, prior to being signed:

  <?xml version="1.0"?>
  <foo ID="abc">
    <bar>123</bar>
  </foo>

Now, let's insert a signature:

  <?xml version="1.0"?>
  <foo ID="abc">
    <bar>123</bar>
    <Signature xmlns="http://www.w3.org/2000/09/xmldsig#">
      <SignedInfo xmlns="http://www.w3.org/2000/09/xmldsig#" xmlns:samlp="urn:oasis:names:tc:SAML:2.0:protocol" xmlns:xenc="http://www.w3.org/2001/04/xmlenc#">
        <CanonicalizationMethod Algorithm="http://www.w3.org/TR/2001/REC-xml-c14n-20010315#WithComments" />
        <SignatureMethod Algorithm="http://www.w3.org/2000/09/xmldsig#rsa-sha1" />
        <Reference URI="#abc">
          <Transforms>
            <Transform Algorithm="http://www.w3.org/2000/09/xmldsig#enveloped-signature" />
          </Transforms>
          <DigestMethod Algorithm="http://www.w3.org/2000/09/xmldsig#sha1" />
          <DigestValue>9kpmrvv3peVJpNSTRycrV+jeHVY=</DigestValue>
        </Reference>
      </SignedInfo>
      <SignatureValue>
        HXUBnMgPJf//j4ihaWnaylNwAR5AzDFY83HljFIlLmTqX1w1C72ZTuRObvYve8TNEbVsQlTQkj4R
        hiY0pgIMQUb75GLYFtc+f0YmBZf5rCWY3NWzo432D3ogAvpEzYXEQPmicWe2QozQhybaz9/wrYki
        XiXY+57fqCkf7aT8Bb6G+fn7Aj8gnZFLkmKxwCdyGsIZOIZdQ8MWpeQrifxBR0d8W1Zm6ix21WNv
        ONt575h7VxLKw8BDhNPS0p8CS3hOnSk29stpiDMCHFPxAwrbKVL1kGDLaLZn1q8nNRmH8oFxG15l
        UmS3JXDZAss8gZhU7g9T4XllCqjrAvzPLOFdeQ==
      </SignatureValue>
      <KeyInfo>
        <KeyValue>
          <RSAKeyValue>
            <Modulus>
              1b+m37u3Xyawh2ArV8txLei251p03CXbkVuWaJu9C8eHy1pu87bcthi+T5WdlCPKD7KGtkKn9vq
              i4BJBZcG/Y10e8KWVlXDLg9gibN5hb0Agae3i1cCJTqqnQ0Ka8w1XABtbxTimS1B0aO1zYW6d+U
              Yl0xIeAOPsGMfWeu1NgLChZQton1/NrJsKwzMaQy1VI8m4gUleit9Z8mbz9bNMshdgYEZ9oC4bH
              n/SnA4FvQl1fjWyTpzL/aWF/bEzS6Qd8IBk7yhcWRJAGdXTWtwiX4mXb4h/2sdrSNvyOsd/shCf
              OSMsf0TX+OdlbH079AsxOwoUjlzjuKdCiFPdU6yAJw==
            </Modulus>
            <Exponent>Iw==</Exponent>
          </RSAKeyValue>
        </KeyValue>
      </KeyInfo>
    </Signature>
  </foo>

SEE ALSO http://www.w3.org/TR/xmldsig-core/

VERSION CONTROL https://github.com/perl-net-saml2/perl-XML-Sig

AUTHORS and CREDITS Author: Byrne Reese byrne@majordojo.com

Thanks to Manni Heumann who wrote Google::SAML::Response from which this
module borrows heavily in order to create digital signatures.

Net::SAML2 embedded version amended by Chris Andrews <chris@nodnol.org>.

Maintainer: Timothy Legge <timlegge@cpan.org>

AUTHORS

COPYRIGHT AND LICENSE This software is copyright (c) 2023 by Byrne Reese, Chris Andrews and Others; in detail:

  Copyright 2009       Byrne, Michael Hendricks
            2010       Chris Andrews
            2011       Chris Andrews, Oskari Okko Ojala
            2012       Chris Andrews, Peter Marschall
            2015       Mike Wisener
            2016       Jeff Fearn
            2017       Mike Wisener, xmikew
            2019-2021  Timothy Legge
            2022-2023  Timothy Legge, Wesley Schwengle

This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.