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<!DOCTYPE erlref SYSTEM "erlref.dtd">
<erlref>
<header>
<copyright>
<year>2008</year>
<year>2013</year>
<holder>Ericsson AB, All Rights Reserved</holder>
</copyright>
<legalnotice>
The contents of this file are subject to the Erlang Public License,
Version 1.1, (the "License"); you may not use this file except in
compliance with the License. You should have received a copy of the
Erlang Public License along with this software. If not, it can be
retrieved online at http://www.erlang.org/.
Software distributed under the License is distributed on an "AS IS"
basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
the License for the specific language governing rights and limitations
under the License.
The Initial Developer of the Original Code is Ericsson AB.
</legalnotice>
<title>public_key</title>
<prepared>Ingela Anderton Andin</prepared>
<responsible></responsible>
<docno></docno>
<date></date>
<rev></rev>
</header>
<module>public_key</module>
<modulesummary> API module for public key infrastructure.</modulesummary>
<description>
<p>This module provides functions to handle public key infrastructure
from <url href="http://www.ietf.org/rfc/rfc5280.txt">RFC 5280</url>- X.509 certificates and some parts of the PKCS-standard.
</p>
</description>
<section>
<title>COMMON DATA TYPES </title>
<note><p>All records used in this manual
<!-- except #policy_tree_node{} -->
are generated from ASN.1 specifications
and are documented in the User's Guide. See <seealso
marker="public_key_records">Public key records</seealso> and <seealso
marker="cert_records">X.509 Certificate records</seealso>.
</p></note>
<p>Use the following include directive to get access to the
records and constant macros described here and in the User's Guide.</p>
<code> -include_lib("public_key/include/public_key.hrl"). </code>
<p><em>Data Types </em></p>
<p><code>boolean() = true | false</code></p>
<p><code>string() = [bytes()]</code></p>
<p><code>der_encoded() = binary()</code></p>
<p><code>pki_asn1_type() = 'Certificate' | 'RSAPrivateKey'| 'RSAPublicKey' |
'DSAPrivateKey' | 'DSAPublicKey' | 'DHParameter' | 'SubjectPublicKeyInfo' |
'PrivateKeyInfo' | 'CertificationRequest'</code></p>
<p><code>pem_entry () = {pki_asn1_type(), binary(), %% DER or encrypted DER
not_encrypted | cipher_info()} </code></p>
<p><code>cipher_info() = {"RC2-CBC | "DES-CBC" | "DES-EDE3-CBC", crypto:rand_bytes(8)} |
'PBES2-params'} </code></p>
<p><code>rsa_public_key() = #'RSAPublicKey'{}</code></p>
<p><code>rsa_private_key() = #'RSAPrivateKey'{} </code></p>
<p><code>dsa_public_key() = {integer(), #'Dss-Parms'{}} </code></p>
<p><code>dsa_private_key() = #'DSAPrivateKey'{}</code></p>
<p><code> public_crypt_options() = [{rsa_pad, rsa_padding()}]. </code></p>
<p><code> rsa_padding() = 'rsa_pkcs1_padding' | 'rsa_pkcs1_oaep_padding'
| 'rsa_no_padding'</code></p>
<p><code> rsa_digest_type() = 'md5' | 'sha' | 'sha224' | 'sha256' | 'sha384' | 'sha512' </code></p>
<p><code> dss_digest_type() = 'sha' </code></p>
<p><code> crl_reason() = unspecified | keyCompromise | cACompromise | affiliationChanged | superseded | cessationOfOperation | certificateHold | privilegeWithdrawn | aACompromise
</code></p>
<p><code> ssh_file() = openssh_public_key | rfc4716_public_key |
known_hosts | auth_keys </code></p>
<!-- <p><code>policy_tree() = [Root, Children]</code></p> -->
<!-- <p><code>Root = #policy_tree_node{}</code></p> -->
<!-- <p><code>Children = [] | policy_tree()</code></p> -->
<!-- <p> The policy_tree_node record has the following fields:</p> -->
<!-- <taglist> -->
<!-- <tag>valid_policy</tag> -->
<!-- <item> Is a single policy OID representing a -->
<!-- valid policy for the path of length x.</item> -->
<!-- <tag>qualifier_set</tag> -->
<!-- <item>A set of policy qualifiers associated -->
<!-- with the valid policy in certificate x.</item> -->
<!-- <tag>critically_indicator</tag> -->
<!-- <item>The critically_indicator indicates whether the -->
<!-- certificate policy extension in certificate x was marked as -->
<!-- critical. </item> -->
<!-- <tag>expected_policy_set</tag> -->
<!-- <item>The expected_policy_set contains one or more policy OIDs -->
<!-- that would satisfy this policy in the certificate x+1. </item> -->
<!-- </taglist> -->
</section>
<funcs>
<func>
<name>decrypt_private(CipherText, Key) -> binary()</name>
<name>decrypt_private(CipherText, Key, Options) -> binary()</name>
<fsummary>Public key decryption.</fsummary>
<type>
<v>CipherText = binary()</v>
<v>Key = rsa_private_key()</v>
<v>Options = public_crypt_options()</v>
</type>
<desc>
<p>Public key decryption using the private key.</p>
</desc>
</func>
<func>
<name>decrypt_public(CipherText, Key) - > binary()</name>
<name>decrypt_public(CipherText, Key, Options) - > binary()</name>
<fsummary></fsummary>
<type>
<v>CipherText = binary()</v>
<v>Key = rsa_public_key()</v>
<v>Options = public_crypt_options()</v>
</type>
<desc>
<p> Public key decryption using the public key.</p>
</desc>
</func>
<func>
<name>der_decode(Asn1type, Der) -> term()</name>
<fsummary> Decodes a public key asn1 der encoded entity.</fsummary>
<type>
<v>Asn1Type = atom()</v>
<d> ASN.1 type present in the public_key applications
asn1 specifications.</d>
<v>Der = der_encoded()</v>
</type>
<desc>
<p> Decodes a public key ASN.1 der encoded entity.</p>
</desc>
</func>
<func>
<name>der_encode(Asn1Type, Entity) -> der_encoded()</name>
<fsummary> Encodes a public key entity with asn1 DER encoding.</fsummary>
<type>
<v>Asn1Type = atom()</v>
<d> Asn1 type present in the public_key applications
ASN.1 specifications.</d>
<v>Entity = term()</v>
<d>The erlang representation of <c>Asn1Type</c></d>
</type>
<desc>
<p> Encodes a public key entity with ASN.1 DER encoding.</p>
</desc>
</func>
<func>
<name>pem_decode(PemBin) -> [pem_entry()]</name>
<fsummary>Decode PEM binary data and return
entries as ASN.1 der encoded entities. </fsummary>
<type>
<v>PemBin = binary()</v>
<d>Example {ok, PemBin} = file:read_file("cert.pem").</d>
</type>
<desc>
<p>Decode PEM binary data and return
entries as ASN.1 der encoded entities.</p>
</desc>
</func>
<func>
<name>pem_encode(PemEntries) -> binary()</name>
<fsummary>Creates a PEM binary</fsummary>
<type>
<v> PemEntries = [pem_entry()] </v>
</type>
<desc>
<p>Creates a PEM binary</p>
</desc>
</func>
<func>
<name>pem_entry_decode(PemEntry) -> term()</name>
<name>pem_entry_decode(PemEntry, Password) -> term()</name>
<fsummary>Decodes a pem entry.</fsummary>
<type>
<v> PemEntry = pem_entry() </v>
<v> Password = string() </v>
</type>
<desc>
<p>Decodes a pem entry. pem_decode/1 returns a list of pem
entries. Note that if the pem entry is of type
'SubjectPublickeyInfo' it will be further decoded to an
rsa_public_key() or dsa_public_key().</p>
</desc>
</func>
<func>
<name>pem_entry_encode(Asn1Type, Entity) -> pem_entry()</name>
<name>pem_entry_encode(Asn1Type, Entity, {CipherInfo, Password}) -> pem_entry()</name>
<fsummary> Creates a pem entry that can be fed to pem_encode/1.</fsummary>
<type>
<v>Asn1Type = pki_asn1_type()</v>
<v>Entity = term()</v>
<d>The Erlang representation of
<c>Asn1Type</c>. If <c>Asn1Type</c> is 'SubjectPublicKeyInfo'
then <c>Entity</c> must be either an rsa_public_key() or a
dsa_public_key() and this function will create the appropriate
'SubjectPublicKeyInfo' entry.
</d>
<v>CipherInfo = cipher_info()</v>
<v>Password = string()</v>
</type>
<desc>
<p> Creates a pem entry that can be feed to pem_encode/1.</p>
</desc>
</func>
<func>
<name>encrypt_private(PlainText, Key) -> binary()</name>
<fsummary> Public key encryption using the private key.</fsummary>
<type>
<v>PlainText = binary()</v>
<v>Key = rsa_private_key()</v>
</type>
<desc>
<p> Public key encryption using the private key.</p>
</desc>
</func>
<func>
<name>encrypt_public(PlainText, Key) -> binary()</name>
<fsummary> Public key encryption using the public key.</fsummary>
<type>
<v>PlainText = binary()</v>
<v>Key = rsa_public_key()</v>
</type>
<desc>
<p> Public key encryption using the public key.</p>
</desc>
</func>
<func>
<name>pkix_decode_cert(Cert, otp|plain) -> #'Certificate'{} | #'OTPCertificate'{}</name>
<fsummary> Decodes an ASN.1 der encoded pkix x509 certificate.</fsummary>
<type>
<v>Cert = der_encoded()</v>
</type>
<desc>
<p>Decodes an ASN.1 der encoded pkix certificate. The otp option
will use the customized ASN.1 specification OTP-PKIX.asn1 for
decoding and also recursively decode most of the standard
parts.</p>
</desc>
</func>
<func>
<name>pkix_encode(Asn1Type, Entity, otp | plain) -> der_encoded()</name>
<fsummary>Der encodes a pkix x509 certificate or part of such a
certificate.</fsummary>
<type>
<v>Asn1Type = atom()</v>
<d>The ASN.1 type can be 'Certificate', 'OTPCertificate' or a subtype of either .</d>
</type>
<desc>
<p>Der encodes a pkix x509 certificate or part of such a
certificate. This function must be used for encoding certificates or parts of certificates
that are decoded/created in the otp format, whereas for the plain format this
function will directly call der_encode/2. </p>
</desc>
</func>
<func>
<name>pkix_is_issuer(Cert, IssuerCert) -> boolean()</name>
<fsummary> Checks if <c>IssuerCert</c> issued <c>Cert</c> </fsummary>
<type>
<v>Cert = der_encode() | #'OTPCertificate'{}</v>
<v>IssuerCert = der_encode() | #'OTPCertificate'{}</v>
</type>
<desc>
<p> Checks if <c>IssuerCert</c> issued <c>Cert</c> </p>
</desc>
</func>
<func>
<name>pkix_is_fixed_dh_cert(Cert) -> boolean()</name>
<fsummary> Checks if a Certificate is a fixed Diffie-Hellman Cert.</fsummary>
<type>
<v>Cert = der_encode() | #'OTPCertificate'{}</v>
</type>
<desc>
<p> Checks if a Certificate is a fixed Diffie-Hellman Cert.</p>
</desc>
</func>
<func>
<name>pkix_is_self_signed(Cert) -> boolean()</name>
<fsummary> Checks if a Certificate is self signed.</fsummary>
<type>
<v>Cert = der_encode() | #'OTPCertificate'{}</v>
</type>
<desc>
<p> Checks if a Certificate is self signed.</p>
</desc>
</func>
<func>
<name>pkix_issuer_id(Cert, IssuedBy) -> {ok, IssuerID} | {error, Reason}</name>
<fsummary> Returns the issuer id.</fsummary>
<type>
<v>Cert = der_encode() | #'OTPCertificate'{}</v>
<v>IssuedBy = self | other</v>
<v>IssuerID = {integer(), {rdnSequence, [#'AttributeTypeAndValue'{}]}}</v>
<d>The issuer id consists of the serial number and the issuers name.</d>
<v>Reason = term()</v>
</type>
<desc>
<p> Returns the issuer id.</p>
</desc>
</func>
<func>
<name>pkix_normalize_name(Issuer) -> Normalized</name>
<fsummary>Normalizes a issuer name so that it can be easily
compared to another issuer name. </fsummary>
<type>
<v>Issuer = {rdnSequence,[#'AttributeTypeAndValue'{}]}</v>
<v>Normalized = {rdnSequence, [#'AttributeTypeAndValue'{}]}</v>
</type>
<desc>
<p>Normalizes a issuer name so that it can be easily
compared to another issuer name.</p>
</desc>
</func>
<func>
<name>pkix_path_validation(TrustedCert, CertChain, Options) -> {ok, {PublicKeyInfo, PolicyTree}} | {error, {bad_cert, Reason}} </name>
<fsummary> Performs a basic path validation according to RFC 5280.</fsummary>
<type>
<v> TrustedCert = #'OTPCertificate'{} | der_encode() | unknown_ca | selfsigned_peer </v>
<d>Normally a trusted certificate but it can also be one of the path validation
errors <c>unknown_ca </c> or <c>selfsigned_peer </c> that can be discovered while
constructing the input to this function and that should be run through the <c>verify_fun</c>.</d>
<v> CertChain = [der_encode()]</v>
<d>A list of DER encoded certificates in trust order ending with the peer certificate.</d>
<v> Options = proplists:proplists()</v>
<v>PublicKeyInfo = {?'rsaEncryption' | ?'id-dsa',
rsa_public_key() | integer(), 'NULL' | 'Dss-Parms'{}}</v>
<v> PolicyTree = term() </v>
<d>At the moment this will always be an empty list as Policies are not currently supported</d>
<v> Reason = cert_expired | invalid_issuer | invalid_signature | unknown_ca |
selfsigned_peer | name_not_permitted | missing_basic_constraint | invalid_key_usage | crl_reason()
</v>
</type>
<desc>
<p>
Performs a basic path validation according to
<url href="http://www.ietf.org/rfc/rfc5280.txt">RFC 5280.</url>
However CRL validation is done separately by <seealso
marker="public_key#pkix_crls_validate-3">pkix_crls_validate/3 </seealso> and should be called
from the supplied <c>verify_fun</c>
</p>
<taglist>
<p> Available options are: </p>
<tag>{verify_fun, fun()}</tag>
<item>
<p>The fun should be defined as:</p>
<code>
fun(OtpCert :: #'OTPCertificate'{}, Event :: {bad_cert, Reason :: atom()} |
{extension, #'Extension'{}},
InitialUserState :: term()) ->
{valid, UserState :: term()} | {valid_peer, UserState :: term()} |
{fail, Reason :: term()} | {unknown, UserState :: term()}.
</code>
<p>If the verify callback fun returns {fail, Reason}, the
verification process is immediately stopped. If the verify
callback fun returns {valid, UserState}, the verification
process is continued, this can be used to accept specific path
validation errors such as <c>selfsigned_peer</c> as well as
verifying application specific extensions. If called with an
extension unknown to the user application the return value
{unknown, UserState} should be used.</p>
</item>
<tag>{max_path_length, integer()}</tag>
<item>
The <c>max_path_length</c> is the maximum number of non-self-issued
intermediate certificates that may follow the peer certificate
in a valid certification path. So if <c>max_path_length</c> is 0 the PEER must
be signed by the trusted ROOT-CA directly, if 1 the path can
be PEER, CA, ROOT-CA, if it is 2 PEER, CA, CA, ROOT-CA and so
on.
</item>
</taglist>
</desc>
</func>
<func>
<name>pkix_crls_validate(OTPCertificate, DPAndCRLs, Options) -> CRLStatus()</name>
<fsummary> Performs CRL validation.</fsummary>
<type>
<v> OTPCertificate = #'OTPCertificate'{}</v>
<v> DPAndCRLs = [{DP::#'DistributionPoint'{} ,CRL::#'CertificateList'{}}] </v>
<v> Options = proplists:proplists()</v>
<v> CRLStatus() = valid | {bad_cert, revocation_status_undetermined} |
{bad_cert, {revoked, crl_reason()}}</v>
</type>
<desc>
<p> Performs CRL validation. It is intended to be called from
the verify fun of <seealso marker="public_key#pkix_path_validation-3"> pkix_path_validation/3
</seealso></p>
<taglist>
<p> Available options are: </p>
<tag>{update_crl, fun()}</tag>
<item>
<p>The fun has the following type spec:</p>
<code> fun(#'DistributionPoint'{}, #'CertificateList'{}) -> #'CertificateList'{}</code>
<p>The fun should use the information in the distribution point to acesses
the lates possible version of the CRL. If this fun is not specified
public_key will use the default implementation:
</p>
<code> fun(_DP, CRL) -> CRL end</code>
</item>
</taglist>
</desc>
</func>
<func>
<name>pkix_sign(#'OTPTBSCertificate'{}, Key) -> der_encode()</name>
<fsummary>Signs certificate.</fsummary>
<type>
<v>Key = rsa_public_key() | dsa_public_key()</v>
</type>
<desc>
<p>Signs a 'OTPTBSCertificate'. Returns the corresponding
der encoded certificate.</p>
</desc>
</func>
<func>
<name>pkix_verify(Cert, Key) -> boolean()</name>
<fsummary> Verify pkix x.509 certificate signature.</fsummary>
<type>
<v>Cert = der_encode()</v>
<v>Key = rsa_public_key() | dsa_public_key()</v>
</type>
<desc>
<p> Verify pkix x.509 certificate signature.</p>
</desc>
</func>
<func>
<name>sign(Msg, DigestType, Key) -> binary()</name>
<fsummary> Create digital signature.</fsummary>
<type>
<v>Msg = binary() | {digest,binary()}</v>
<d>The msg is either the binary "plain text" data to be
signed or it is the hashed value of "plain text" i.e. the
digest.</d>
<v>DigestType = rsa_digest_type() | dss_digest_type()</v>
<v>Key = rsa_private_key() | dsa_private_key()</v>
</type>
<desc>
<p> Creates a digital signature.</p>
</desc>
</func>
<func>
<name>ssh_decode(SshBin, Type) -> [{public_key(), Attributes::list()}]</name>
<fsummary>Decodes a ssh file-binary. </fsummary>
<type>
<v>SshBin = binary()</v>
<d>Example {ok, SshBin} = file:read_file("known_hosts").</d>
<v> Type = public_key | ssh_file()</v>
<d>If <c>Type</c> is <c>public_key</c> the binary may be either
a rfc4716 public key or a openssh public key.</d>
</type>
<desc>
<p> Decodes a ssh file-binary. In the case of know_hosts or
auth_keys the binary may include one or more lines of the
file. Returns a list of public keys and their attributes, possible
attribute values depends on the file type represented by the
binary.
</p>
<taglist>
<tag>rfc4716 attributes - see RFC 4716</tag>
<item>{headers, [{string(), utf8_string()}]}</item>
<tag>auth_key attributes - see man sshd </tag>
<item>{comment, string()}</item>
<item>{options, [string()]}</item>
<item>{bits, integer()} - In ssh version 1 files</item>
<tag>known_host attributes - see man sshd</tag>
<item>{hostnames, [string()]}</item>
<item>{comment, string()}</item>
<item>{bits, integer()} - In ssh version 1 files</item>
</taglist>
</desc>
</func>
<func>
<name>ssh_encode([{Key, Attributes}], Type) -> binary()</name>
<fsummary> Encodes a list of ssh file entries to a binary.</fsummary>
<type>
<v>Key = public_key()</v>
<v>Attributes = list()</v>
<v>Type = ssh_file()</v>
</type>
<desc>
<p>Encodes a list of ssh file entries (public keys and attributes) to a binary. Possible
attributes depends on the file type, see <seealso
marker="#ssh_decode-2"> ssh_decode/2 </seealso></p>
</desc>
</func>
<func>
<name>verify(Msg, DigestType, Signature, Key) -> boolean()</name>
<fsummary>Verifies a digital signature.</fsummary>
<type>
<v>Msg = binary() | {digest,binary()}</v>
<d>The msg is either the binary "plain text" data
or it is the hashed value of "plain text" i.e. the digest.</d>
<v>DigestType = rsa_digest_type() | dss_digest_type()</v>
<v>Signature = binary()</v>
<v>Key = rsa_public_key() | dsa_public_key()</v>
</type>
<desc>
<p>Verifies a digital signature</p>
</desc>
</func>
</funcs>
</erlref>
