Merge branch 'dev' of super:otp into dev

* 'dev' of super:otp: (166 commits)
  Corrected documentation error and added examples to Users Guide
  In TLS 1.1, failure to properly close a connection no longer requires that a session not be resumed.  This is a change from TLS 1.0 to conform with widespread implementation practice.  Erlang ssl will now in TLS 1.0 conform to the widespread implementation practice instead of the specification to avoid performance issues.
  Add escript to bootstrap/bin
  Remove unused variable warning in inet_res
  Remove unused variable in epmd_port
  Remove compiler warnings in inet_drv
  Add SASL test suite
  Allow same module name in multiple applications if explicitely excluded
  Fix bugs concerning the option report_missing_types
  Fix default encoding in SAX parser.
  re: remove gratuitous "it " in manpage
  Spelling in (backward *compatibility*) comment.
  Improve erl_docgen's support for Dialyzer specs and types
  dialyzer warning on mnesia_tm
  Add documentation text about majority checking
  add mnesia_majority_test suite
  where_to_wlock optimization + change_table_majority/2
  bug in mnesia_tm:needs_majority/2
  optimize sticky_lock maj. check
  check majority for sticky locks
  ...

5 files changed, 521 insertions, 15 deletions

diff --git a/lib/public_key/doc/src/Makefile b/lib/public_key/doc/src/Makefile
index 298c28a740..afb17399da 100644
--- a/lib/public_key/doc/src/Makefile
+++ b/lib/public_key/doc/src/Makefile
@@ -1,7 +1,7 @@
 #
 # %CopyrightBegin%
 #
-# Copyright Ericsson AB 2008-2010. All Rights Reserved.
+# Copyright Ericsson AB 2008-2011. All Rights Reserved.
 #
 # 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
@@ -52,6 +52,7 @@ XML_CHAPTER_FILES = \
 	introduction.xml \
 	public_key_records.xml \
 	cert_records.xml \
+	using_public_key.xml \
 	notes.xml
 
 BOOK_FILES = book.xml
diff --git a/lib/public_key/doc/src/notes.xml b/lib/public_key/doc/src/notes.xml
index 14b43041ce..30326da114 100644
--- a/lib/public_key/doc/src/notes.xml
+++ b/lib/public_key/doc/src/notes.xml
@@ -5,7 +5,7 @@
   <header>
     <copyright>
       <year>2008</year>
-      <year>2010</year>
+      <year>2011</year>
       <holder>Ericsson AB, All Rights Reserved</holder>
     </copyright>
     <legalnotice>
diff --git a/lib/public_key/doc/src/part.xml b/lib/public_key/doc/src/part.xml
index c338a71613..ea3123b5bd 100644
--- a/lib/public_key/doc/src/part.xml
+++ b/lib/public_key/doc/src/part.xml
@@ -1,4 +1,4 @@
-<?xml version="1.0" encoding="latin1" ?>
+<?xml version="1.0" encoding="iso-8859-1" ?>
 <!DOCTYPE part SYSTEM "part.dtd">
 
 <part xmlns:xi="http://www.w3.org/2001/XInclude">
@@ -38,5 +38,6 @@
   <xi:include href="introduction.xml"/>
   <xi:include href="public_key_records.xml"/>
   <xi:include href="cert_records.xml"/>
+  <xi:include href="using_public_key.xml"/>
 </part>
 
diff --git a/lib/public_key/doc/src/public_key.xml b/lib/public_key/doc/src/public_key.xml
index c5f57214b1..d60d91cd83 100644
--- a/lib/public_key/doc/src/public_key.xml
+++ b/lib/public_key/doc/src/public_key.xml
@@ -43,7 +43,7 @@
     
     <note><p>All records used in this manual 
     <!--     except #policy_tree_node{}  -->
-    are generated from asn1 specifications
+    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>. 
@@ -150,12 +150,12 @@
     <fsummary> Decodes a public key asn1 der encoded entity.</fsummary>
     <type>
       <v>Asn1Type = atom() -</v>
-      <d> Asn1 type present in the public_key applications
+      <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 asn1 der encoded entity.</p> 
+      <p> Decodes a public key ASN.1 der encoded entity.</p>
     </desc> 
   </func>
     
@@ -165,25 +165,25 @@
     <type>
       <v>Asn1Type = atom()</v>
       <d> Asn1 type present in the public_key applications
-	 asn1 specifications.</d>
+	 ASN.1 specifications.</d>
       <v>Entity = term() - The erlang representation of <c> Asn1Type</c></v>
   </type> 
   <desc> 
-    <p> Encodes a public key entity with asn1 DER encoding.</p> 
+    <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 asn1 der encoded entities. </fsummary>
+    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 asn1 der encoded entities.</p> 
+    entries as ASN.1 der encoded entities.</p>
   </desc> 
   </func> 
     
@@ -258,13 +258,13 @@
   
   <func>
     <name>pkix_decode_cert(Cert, otp|plain) ->  #'Certificate'{} | #'OTPCertificate'{}</name>
-    <fsummary> Decodes an asn1 der encoded pkix x509 certificate.</fsummary>
+    <fsummary> Decodes an ASN.1 der encoded pkix x509 certificate.</fsummary>
     <type>
       <v>Cert = der_encoded()</v> 
   </type> 
   <desc> 
-    <p>Decodes an asn1 der encoded pkix certificate.  The otp option
-    will use the customized asn1 specification OTP-PKIX.asn1 for
+    <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> 
@@ -276,7 +276,7 @@
     certificate.</fsummary>
     <type>
       <v>Asn1Type = atom()</v>
-      <d>The asn1 type can be 'Certificate', 'OTPCertificate' or a subtype of either .</d>
+      <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
@@ -394,7 +394,7 @@
        signed or in the case that digest type is <c>none</c>
        it is the hashed value of "plain text" i.e. the digest.</d>
        <v>DigestType = rsa_digest_type() | dsa_digest_type()</v>
-       <v>Key = rsa_public_key() | dsa_public_key()</v> 
+       <v>Key = rsa_private_key() | dsa_private_key()</v>
   </type> 
   <desc> 
     <p> Creates a digital signature.</p> 
diff --git a/lib/public_key/doc/src/using_public_key.xml b/lib/public_key/doc/src/using_public_key.xml
new file mode 100644
index 0000000000..f0eaeb8654
--- /dev/null
+++ b/lib/public_key/doc/src/using_public_key.xml
@@ -0,0 +1,504 @@
+<?xml version="1.0" encoding="iso-8859-1" ?>
+<!DOCTYPE chapter SYSTEM "chapter.dtd">
+
+<chapter>
+  <header>
+    <copyright>
+      <year>2011</year><year>2011</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.
+    
+    </legalnotice>
+
+    <title>Using the public_key API</title>
+    <file>using_public_key.xml</file>
+  </header>
+
+  <section>
+    <title>General information</title>
+
+    <p> This chapter is dedicated to showing some
+    examples of how to use the public_key API. Keys and certificates
+    used in the following sections are generated only for the purpose
+    of testing the public key application.</p>
+
+    <p>Note that some shell printouts, in the following examples,
+    have been abbreviated for increased readability.</p>
+    
+  </section>
+    
+  <section>
+    <title>PEM files</title>
+    <p> Pulic key data (keys, certificates etc) may be stored in PEM format. PEM files
+    comes from the Private Enhanced Mail Internet standard and has a
+    structure that looks like this:</p>
+
+    <code>&lt;text&gt;
+	-----BEGIN &lt;SOMETHING&gt;-----
+	&lt;Attribute&gt; : &lt;Value&gt;
+	&lt;Base64 encoded DER data&gt;
+	-----END &lt;SOMETHING&gt;-----
+	&lt;text&gt;</code>
+
+    <p>A file can contain several BEGIN/END blocks. Text lines between
+    blocks are ignored.  Attributes, if present, are currently ignored except
+    for <c>Proc-Type</c> and <c>DEK-Info</c> that are used when the DER data is
+    encrypted.</p>
+
+    <section>
+      <title>DSA private key</title>
+      
+      <p>Note file handling is not done by the public_key application. </p>
+      <code>1> {ok, PemBin} = file:read_file("dsa.pem").
+{ok,&lt;&lt;"-----BEGIN DSA PRIVATE KEY-----\nMIIBuw"...&gt;&gt;}</code>
+      
+      <p>This PEM file only has one entry a private DSA key.</p>
+      <code>2> [DSAEntry] =  public_key:pem_decode(PemBin).
+[{'DSAPrivateKey',&lt;&lt;48,130,1,187,2,1,0,2,129,129,0,183,
+                    179,230,217,37,99,144,157,21,228,204,
+		    162,207,61,246,...&gt;&gt;,
+		    not_encrypted}]</code>
+      
+      <code>3> Key = public_key:pem_entry_decode(DSAEntry).
+#'DSAPrivateKey'{version = 0,
+                 p = 12900045185019966618...6593,
+                 q = 1216700114794736143432235288305776850295620488937,
+                 g = 10442040227452349332...47213,
+                 y = 87256807980030509074...403143,
+                 x = 510968529856012146351317363807366575075645839654}</code>
+    </section>
+
+    <section>
+      <title>RSA private key encrypted with a password.</title>
+      
+      <code>1> {ok, PemBin} = file:read_file("rsa.pem").
+{ok,&lt;&lt;"Bag Attribut"...&gt;&gt;}</code>
+
+    <p>This PEM file only has one entry a private RSA key.</p>
+    <code>2>[RSAEntry] = public_key:pem_decode(PemBin).
+[{'RSAPrivateKey',&lt;&lt;224,108,117,203,152,40,15,77,128,126,
+                    221,195,154,249,85,208,202,251,109,
+                    119,120,57,29,89,19,9,...&gt;&gt;,
+                  {"DES-EDE3-CBC",&lt;&lt;"k�e��p�L"&gt;&gt;}}]
+
+    </code>
+
+    <p>In this example the password is "abcd1234".</p>
+    <code>3> Key = public_key:pem_entry_decode(RSAEntry, "abcd1234").
+    #'RSAPrivateKey'{version = 'two-prime',
+                 modulus = 1112355156729921663373...2737107,
+                 publicExponent = 65537,
+                 privateExponent = 58064406231183...2239766033,
+                 prime1 = 11034766614656598484098...7326883017,
+                 prime2 = 10080459293561036618240...77738643771,
+                 exponent1 = 77928819327425934607...22152984217,
+                 exponent2 = 36287623121853605733...20588523793,
+                 coefficient = 924840412626098444...41820968343,
+                 otherPrimeInfos = asn1_NOVALUE}</code>
+    </section>
+  
+  <section>
+    <title>X509 Certificates</title>
+    
+      <code>1> {ok, PemBin} = file:read_file("cacerts.pem").
+{ok,&lt;&lt;"-----BEGIN CERTIFICATE-----\nMIIC7jCCAl"...&gt;&gt;}</code>
+
+      <p>This file includes two certificates</p>
+      <code>2> [CertEntry1, CertEntry2] = public_key:pem_decode(PemBin).
+[{'Certificate',&lt;&lt;48,130,2,238,48,130,2,87,160,3,2,1,2,2,
+                  9,0,230,145,97,214,191,2,120,150,48,13,
+                  ...&gt;&gt;,
+                not_encrypted},
+ {'Certificate',&lt;&lt;48,130,3,200,48,130,3,49,160,3,2,1,2,2,1,
+                  1,48,13,6,9,42,134,72,134,247,...&gt;&gt;>,
+                not_encrypted}]</code>
+      
+      <p>Certificates may of course be decoded as usual ... </p>
+      <code>2> Cert = public_key:pem_entry_decode(CertEntry1).
+#'Certificate'{
+    tbsCertificate =
+        #'TBSCertificate'{
+            version = v3,serialNumber = 16614168075301976214,
+            signature =
+                #'AlgorithmIdentifier'{
+                    algorithm = {1,2,840,113549,1,1,5},
+                    parameters = &lt;&lt;5,0&gt;&gt;},
+            issuer =
+                {rdnSequence,
+                    [[#'AttributeTypeAndValue'{
+                          type = {2,5,4,3},
+                          value = &lt;&lt;19,8,101,114,108,97,110,103,67,65&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,11},
+                          value = &lt;&lt;19,10,69,114,108,97,110,103,32,79,84,80&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,10},
+                          value = &lt;&lt;19,11,69,114,105,99,115,115,111,110,32,65,66&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,7},
+                          value = &lt;&lt;19,9,83,116,111,99,107,104,111,108,109&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,6},
+                          value = &lt;&lt;19,2,83,69&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {1,2,840,113549,1,9,1},
+                          value = &lt;&lt;22,22,112,101,116,101,114,64,101,114,...&gt;&gt;}]]},
+            validity =
+                #'Validity'{
+                    notBefore = {utcTime,"080109082929Z"},
+                    notAfter = {utcTime,"080208082929Z"}},
+            subject =
+                {rdnSequence,
+                    [[#'AttributeTypeAndValue'{
+                          type = {2,5,4,3},
+                          value = &lt;&lt;19,8,101,114,108,97,110,103,67,65&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,11},
+                          value = &lt;&lt;19,10,69,114,108,97,110,103,32,79,84,80&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,10},
+                          value = &lt;&lt;19,11,69,114,105,99,115,115,111,110,32,...&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,7},
+                          value = &lt;&lt;19,9,83,116,111,99,107,104,111,108,...&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,6},
+                          value = &lt;&lt;19,2,83,69&gt;&gt;}],
+                     [#'AttributeTypeAndValue'{
+                          type = {1,2,840,113549,1,9,1},
+                          value = &lt;&lt;22,22,112,101,116,101,114,64,...&gt;&gt;}]]},
+            subjectPublicKeyInfo =
+                #'SubjectPublicKeyInfo'{
+                    algorithm =
+                        #'AlgorithmIdentifier'{
+                            algorithm = {1,2,840,113549,1,1,1},
+                            parameters = &lt;&lt;5,0&gt;&gt;},
+                    subjectPublicKey =
+                        {0,&lt;&lt;48,129,137,2,129,129,0,203,209,187,77,73,231,90,...&gt;&gt;}},
+            issuerUniqueID = asn1_NOVALUE,
+            subjectUniqueID = asn1_NOVALUE,
+            extensions =
+                [#'Extension'{
+                     extnID = {2,5,29,19},
+                     critical = true,
+                     extnValue = [48,3,1,1,255]},
+                 #'Extension'{
+                     extnID = {2,5,29,15},
+                     critical = false,
+                     extnValue = [3,2,1,6]},
+                 #'Extension'{
+                     extnID = {2,5,29,14},
+                     critical = false,
+                     extnValue = [4,20,27,217,65,152,6,30,142|...]},
+                 #'Extension'{
+                     extnID = {2,5,29,17},
+                     critical = false,
+                     extnValue = [48,24,129,22,112,101,116,101|...]}]},
+    signatureAlgorithm =
+        #'AlgorithmIdentifier'{
+            algorithm = {1,2,840,113549,1,1,5},
+            parameters = &lt;&lt;5,0&gt;&gt;},
+    signature =
+        {0,
+         &lt;&lt;163,186,7,163,216,152,63,47,154,234,139,73,154,96,120,
+           165,2,52,196,195,109,167,192,...&gt;&gt;}}
+</code>
+
+      <p> Parts of certificates can be decoded with
+      public_key:der_decode/2 using that parts ASN.1 type.
+      Although application specific certificate
+      extension requires application specific ASN.1 decode/encode-functions.
+      Example, the first value of the rdnSequence above is of ASN.1 type
+      'X520CommonName'. ({2,5,4,3} = ?id-at-commonName)</p>
+      
+      <code>public_key:der_decode('X520CommonName', &lt;&lt;19,8,101,114,108,97,110,103,67,65&gt;&gt;).
+{printableString,"erlangCA"}</code>
+
+      <p>... but certificates can also be decode using the pkix_decode_cert/2 that
+      can customize and recursively decode standard parts of a certificate.</p>
+      <code>3>{_, DerCert, _} = CertEntry1.</code>
+      <code>4> public_key:pkix_decode_cert(DerCert, otp).
+#'OTPCertificate'{
+    tbsCertificate =
+        #'OTPTBSCertificate'{
+            version = v3,serialNumber = 16614168075301976214,
+            signature =
+                #'SignatureAlgorithm'{
+                    algorithm = {1,2,840,113549,1,1,5},
+                    parameters = 'NULL'},
+            issuer =
+                {rdnSequence,
+                    [[#'AttributeTypeAndValue'{
+                          type = {2,5,4,3},
+                          value = {printableString,"erlangCA"}}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,11},
+                          value = {printableString,"Erlang OTP"}}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,10},
+                          value = {printableString,"Ericsson AB"}}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,7},
+                          value = {printableString,"Stockholm"}}],
+                     [#'AttributeTypeAndValue'{type = {2,5,4,6},value = "SE"}],
+                     [#'AttributeTypeAndValue'{
+                          type = {1,2,840,113549,1,9,1},
+                          value = "[email protected]"}]]},
+            validity =
+                #'Validity'{
+                    notBefore = {utcTime,"080109082929Z"},
+                    notAfter = {utcTime,"080208082929Z"}},
+            subject =
+                {rdnSequence,
+                    [[#'AttributeTypeAndValue'{
+                          type = {2,5,4,3},
+                          value = {printableString,"erlangCA"}}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,11},
+                          value = {printableString,"Erlang OTP"}}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,10},
+                          value = {printableString,"Ericsson AB"}}],
+                     [#'AttributeTypeAndValue'{
+                          type = {2,5,4,7},
+                          value = {printableString,"Stockholm"}}],
+                     [#'AttributeTypeAndValue'{type = {2,5,4,6},value = "SE"}],
+                     [#'AttributeTypeAndValue'{
+                          type = {1,2,840,113549,1,9,1},
+                          value = "[email protected]"}]]},
+            subjectPublicKeyInfo =
+                #'OTPSubjectPublicKeyInfo'{
+                    algorithm =
+                        #'PublicKeyAlgorithm'{
+                            algorithm = {1,2,840,113549,1,1,1},
+                            parameters = 'NULL'},
+                    subjectPublicKey =
+                        #'RSAPublicKey'{
+                            modulus =
+                                1431267547247997...37419,
+                            publicExponent = 65537}},
+            issuerUniqueID = asn1_NOVALUE,
+            subjectUniqueID = asn1_NOVALUE,
+            extensions =
+                [#'Extension'{
+                     extnID = {2,5,29,19},
+                     critical = true,
+                     extnValue =
+                         #'BasicConstraints'{
+                             cA = true,pathLenConstraint = asn1_NOVALUE}},
+                 #'Extension'{
+                     extnID = {2,5,29,15},
+                     critical = false,
+                     extnValue = [keyCertSign,cRLSign]},
+                 #'Extension'{
+                     extnID = {2,5,29,14},
+                     critical = false,
+                     extnValue = [27,217,65,152,6,30,142,132,245|...]},
+                 #'Extension'{
+                     extnID = {2,5,29,17},
+                     critical = false,
+                     extnValue = [{rfc822Name,"[email protected]"}]}]},
+    signatureAlgorithm =
+        #'SignatureAlgorithm'{
+            algorithm = {1,2,840,113549,1,1,5},
+            parameters = 'NULL'},
+    signature =
+        {0,
+         &lt;&lt;163,186,7,163,216,152,63,47,154,234,139,73,154,96,120,
+           165,2,52,196,195,109,167,192,...&gt;&gt;}}
+</code>
+
+      <p>This call is equivalent to public_key:pem_entry_decode(CertEntry1)</p>
+      <code>5> public_key:pkix_decode_cert(DerCert, plain).
+#'Certificate'{ ...}
+</code>
+  </section>
+
+  <section>
+    <title>Encoding public key data to PEM format</title>
+
+    <p>If you have public key data and and want to create a PEM file
+    you can do that by calling the functions
+    public_key:pem_entry_encode/2 and pem_encode/1 and then saving the
+    result to a file. For example assume you have PubKey =
+    'RSAPublicKey'{} then you can create a PEM-"RSA PUBLIC KEY" file
+    (ASN.1 type 'RSAPublicKey') or a PEM-"PUBLIC KEY" file
+    ('SubjectPublicKeyInfo' ASN.1 type).</p>
+
+    <p> The second element of the PEM-entry will be the ASN.1 DER encoded
+    key data.</p>
+
+    <code>1> PemEntry = public_key:pem_entry_encode('RSAPublicKey', RSAPubKey).
+{'RSAPublicKey', &lt;&lt;48,72,...&gt;&gt;, not_encrypted}
+
+2> PemBin = public_key:pem_encode([PemEntry]).
+&lt;&lt;"-----BEGIN RSA PUBLIC KEY-----\nMEgC...&gt;&gt;
+
+3> file:write_file("rsa_pub_key.pem", PemBin).
+ok</code>
+
+    <p> or </p>
+
+    <code>1> PemBin = public_key:pem_entry_encode('SubjectPublicKeyInfo', RSAPubKey).
+{'SubjectPublicKeyInfo', &lt;&lt;48,92...&gt;&gt;, not_encrypted}
+
+2> PemBin = public_key:pem_encode([PemEntry]).
+&lt;&lt;"-----BEGIN PUBLIC KEY-----\nMFw...&gt;&gt;
+
+3> file:write_file("pub_key.pem", PemBin).
+ok</code>
+
+  </section>
+</section>
+
+<section>
+      <title>RSA public key cryptography </title>
+       <p> Suppose you have PrivateKey = #'RSAPrivateKey{}' and the
+       plaintext Msg = binary() and the corresponding public key
+       PublicKey = #'RSAPublicKey'{} then you can do the following.
+       Note that you normally will only do one of the encrypt or
+       decrypt operations and the peer will do the other.
+       </p>
+
+       <p>Encrypt with the private key </p>
+       <code>RsaEncrypted = public_key:encrypt_private(Msg, PrivateKey),
+Msg = public_key:decrypt_public(RsaEncrypted, PublicKey),</code>
+
+       <p>Encrypt with the public key </p>
+       <code>RsaEncrypted = public_key:encrypt_public(Msg, PublicKey),
+Msg = public_key:decrypt_private(RsaEncrypted, PrivateKey),</code>
+  </section>
+
+  <section>
+    <title>Digital signatures</title>
+
+    <p> Suppose you have PrivateKey = #'RSAPrivateKey{}'or
+    #'DSAPrivateKey'{} and the plaintext Msg = binary() and the
+    corresponding public key PublicKey = #'RSAPublicKey'{} or
+    {integer(), #'DssParams'{}} then you can do the following.  Note
+    that you normally will only do one of the sign or verify operations
+    and the peer will do the other. </p>
+
+    <code>Signature = public_key:sign(Msg, sha, PrivateKey),
+true = public_key:verify(Msg, sha, Signature, PublicKey),</code>
+
+    <p>It might be appropriate to calculate the message digest before
+    calling sign or verify and then you can use the none as second
+    argument.</p>
+
+    <code>Digest = crypto:sha(Msg),
+Signature = public_key:sign(Digest, none, PrivateKey),
+true = public_key:verify(Digest, none, Signature, PublicKey),
+    </code>
+    
+  </section>
+  
+  <section>
+    <title>SSH files</title>
+    
+    <p>SSH typically uses PEM files for private keys but has its
+    own file format for storing public keys. The erlang public_key
+    application can be used to parse the content of SSH public key files.</p>
+
+    <section>
+   <title> RFC 4716 SSH public key files </title>
+
+    <p>RFC 4716 SSH files looks confusingly like PEM files,
+       but there are some differences.</p>
+      <code>1> {ok, SshBin} = file:read_file("ssh2_rsa_pub").
+{ok, &lt;&lt;"---- BEGIN SSH2 PUBLIC KEY ----\nAAAA"...&gt;&gt;}</code>
+
+    <p>This is equivalent to calling public_key:ssh_decode(SshBin, rfc4716_public_key).
+    </p>
+      <code>2> public_key:ssh_decode(SshBin, public_key).
+[{#'RSAPublicKey'{modulus = 794430685...91663,
+                  publicExponent = 35}, []}]
+</code>
+
+ </section>
+
+ <section>
+   <title> Openssh public key format </title>
+      <code>1> {ok, SshBin} = file:read_file("openssh_dsa_pub").
+{ok,&lt;&lt;"ssh-dss AAAAB3Nza"...&gt;&gt;}</code>
+
+    <p>This is equivalent to calling public_key:ssh_decode(SshBin, openssh_public_key).
+    </p>
+    <code>2>  public_key:ssh_decode(SshBin, public_key).
+[{{15642692...694280725,
+   #'Dss-Parms'{p = 17291273936...696123221,
+                q = 1255626590179665817295475654204371833735706001853,
+                g = 10454211196...480338645}},
+  [{comment,"dhopson@VMUbuntu-DSH"}]}]
+</code>
+ </section>
+
+ <section>
+   <title> Known hosts - openssh format</title>
+
+      <code>1> {ok, SshBin} = file:read_file("known_hosts").
+{ok,&lt;&lt;"hostname.domain.com,192.168.0.1 ssh-rsa AAAAB...&gt;&gt;}</code>
+
+    <p>Returns a list of public keys and their related attributes
+    each pair of key and attributes corresponds to one entry in
+    the known hosts file.</p>
+    
+    <code>2>  public_key:ssh_decode(SshBin, known_hosts).
+[{#'RSAPublicKey'{modulus = 1498979460408...72721699,
+                  publicExponent = 35},
+  [{hostnames,["hostname.domain.com","192.168.0.1"]}]},
+ {#'RSAPublicKey'{modulus = 14989794604088...2721699,
+                  publicExponent = 35},
+  [{comment,"[email protected]"},
+   {hostnames,["|1|BWO5qDxk/cFH0wa05JLdHn+j6xQ=|rXQvIxh5cDD3C43k5DPDamawVNA="]}]}]
+</code>
+  </section>
+
+  <section>
+    <title> Authorized keys - openssh format</title>
+
+    <code>1> {ok, SshBin} = file:read_file("auth_keys").
+{ok, &lt;&lt;"command=\"dump /home\",no-pty,no-port-forwarding ssh-rsa AAA...&gt;&gt;}</code>
+
+    <p>Returns a list of public keys and their related attributes
+    each pair of key and attributes corresponds to one entry in
+    the authorized key file.</p>
+
+    <code>2> public_key:ssh_decode(SshBin, auth_keys).
+[{#'RSAPublicKey'{modulus = 794430685...691663,
+                  publicExponent = 35},
+  [{comment,"dhopson@VMUbuntu-DSH"},
+   {options,["command=\"dump/home\"","no-pty",
+             "no-port-forwarding"]}]},
+ {{1564269258491...607694280725,
+   #'Dss-Parms'{p = 17291273936185...763696123221,
+                q = 1255626590179665817295475654204371833735706001853,
+                g = 10454211195705...60511039590076780999046480338645}},
+  [{comment,"dhopson@VMUbuntu-DSH"}]}]
+</code>
+    </section>
+
+    <section>
+      <title> Creating an SSH file from public key data </title>
+
+      <p>If you got a public key <c>PubKey</c> and a related list of
+      attributes <c>Attributes</c> as returned
+      by ssh_decode/2 you can create a new ssh file for example</p>
+      <code>N> SshBin = public_key:ssh_encode([{PubKey, Attributes}], openssh_public_key),
+&lt;&lt;"ssh-rsa "...&gt;&gt;
+N+1> file:write_file("id_rsa.pub", SshBin).
+ok</code>
+    </section>
+  </section>
+</chapter>