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CA構築編、サーバ証明書編、と続いたクライアント証明の実現方法ですが、いよいよ「クライアント証明書」編の始まりです。

ユーザディレクトリに移動します。
# cd /usr/local/ssl

秘密鍵を2048bitで作成します。
# openssl genrsa -out client.private.pem 2048

---

Generating RSA private key, 2048 bit long modulus
.....................................................................+++
....+++
e is 65537 (0x10001)

---

秘密鍵を使用して署名リクエスト(公開鍵)を作成します。クライアント(ユーザ)単位に適用する証明書なので、ユーザ名がわかる名前を付けます。
# openssl req -new -key client.private.pem -out admin.free-style.biz.pem

---

You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [JP]:
→そのままEnterキー
State or Province Name (full name) [Tokyo]:
→そのままEnterキー
Locality Name (eg, city) [Shinagawa-ku]:
→そのままEnterキー
Organization Name (eg, company) [Fs DataCenter CA]:
→そのままEnterキー
Organizational Unit Name (eg, section) []:
→そのままEnterキー
Common Name (eg, your name or your server's hostname) []:
→ユーザ名(admin)を入力します。(各自お好みで)
Email Address []:
→ユーザのメールアドレス(admin@free-style.biz)を入力します。

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
→そのままEnterキー
An optional company name []:
→フレンドリ名(admin)を入力します。(各自お好みで)

---

「Netscape用」と言われていますが、クライアントで使用するために署名リクエスト(公開鍵)にCAの認証を付加します。
# cd /etc/pki/tls/misc
# openssl ca -out /usr/local/ssl/admin.free-style.biz.crt -infiles /usr/local/ssl/admin.free-style.biz.pem

---

Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for ../../CA/private/cakey.pem:
→CAの秘密鍵のパスフレーズを入力します。
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number: 6 (0x6)
Validity
Not Before: Jul 9 06:40:46 2010 GMT
Not After : Jul 8 06:40:46 2020 GMT
Subject:
countryName = JP
stateOrProvinceName = Tokyo
organizationName = Fs DataCenter CA
commonName = admin
emailAddress = admin@free-style.biz
X509v3 extensions:
X509v3 Basic Constraints:
CA:TRUE
Netscape Cert Type:
SSL Client, SSL Server, S/MIME, Object Signing
X509v3 Subject Key Identifier:
D6:4C:45:72:6E:17:9B:94:8F:C4:C1:8A:C0:43:69:59:4B:E5:A6:87
X509v3 Authority Key Identifier:
keyid:AF:3D:E9:BC:17:83:29:D7:C0:4D:3F:E0:32:51:2C:BF:B1:B4:0A:00

Certificate is to be certified until Jul 8 06:40:46 2020 GMT (3652 days)
Sign the certificate? [y/n]:
→「証明書に署名しますか？」と聞かれるので、素直に「y」

1 out of 1 certificate requests certified, commit? [y/n]
→「署名リクエストを作成しますか？」と聞かれるので、素直に「y」

Write out database with 1 new entries
Data Base Updated

---

クライアントに組み込むためにp12形式のファイルを作成します。
-export　→　クライアントの署名リクエストファイル名
-inkey　→　クライアントの秘密鍵ファイル名
-certfile　→　CAの公開鍵ファイル名
-name　→　フレンドリ名
-caname　→　ルートCA(サーバ証明書のホスト名)
-out　→　p12形式の出力ファイル名
# openssl pkcs12 -export -in /usr/local/ssl/admin.free-style.biz.crt -inkey /usr/local/ssl/client.private.pem -certfile /etc/pki/CA/cacert.pem -name admin -caname ca1.free-style.biz -out /usr/local/ssl/admin.free-style.biz.p12

---

Enter Export Password:
→バックアップ用パスワードを入力します。クライアントへのインストール時に必要になります。
Verifying - Enter Export Password:
→もう一度バックアップ用パスワードを入力します。

---

これでクライアント証明書の完成です。先に作成した「サーバ証明書」と今回の「クライアント証明書」の２つをクライアントにインストールすれば、おれおれS/MIMEが使用できるようになります。

以下、参考にしたサイト。CAを作成しないパターンや古い情報もあるので注意！

S/MIMEでセキュアなメール送信 in PHP

S/MIME(Secure MIME)で電子メールを交換する個人証明書作成を試す

CentOS5.3でオレオレCA局+SSL認証の作り方

SSLおれおれ証明書とクライアント認証

おれおれCA（プライベート認証局）が構築できたところで、「サーバ証明書」を作成していきます。いわゆる「ルート証明書」に当たるものです。

サーバ証明書の作成は、秘密鍵を作って、署名リクエストを作成して、CAに認証させるという手順を踏むのですが、CAを新しく作る手順の場合は、このCA作成のなかでほとんどの手順が終了してしまっています。

それではできている公開鍵が認証できるかどうか確認してみましょう。
# openssl verify /etc/pki/CA/cacert.pem

---

cacert.pem: /C=JP/ST=Tokyo/L=Shinagawa-ku/O=Fs DataCenter CA/CN=ca1.free-style.biz
error 18 at 0 depth lookup:self signed certificate
OK

---

SSL証明書用のユーザディレクトリを作成して、移動します。
# mkdir /usr/local/ssl
# cd /usr/local/ssl

クライアントに組み込むためのサーバ証明書を作成します。
# openssl x509 -inform pem -in /etc/pki/CA/cacert.pem -out ca1.free-style.biz.crt -outform der

これで終わりです。

というのもあんまりですので、別に証明書を作成して署名してみましょう。

証明書はユーザディレクトリに作成します。
# cd /usr/local/ssl

新しく秘密鍵を2048bitで生成します。
# openssl genrsa -out private.pem 2048

---

Generating RSA private key, 2048 bit long modulus
..+++
..........................+++
e is 65537 (0x10001)

---

秘密鍵を使用して署名リクエスト(公開鍵)を作成します。
# openssl req -new -key private.pem -out request.pem

---

You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [JP]:
→そのままEnterキー
State or Province Name (full name) [Tokyo]:
→そのままEnterキー
Locality Name (eg, city) [Shinagawa-ku]:
→そのままEnterキー
Organization Name (eg, company) [Fs DataCenter CA]:
→そのままEnterキー
Organizational Unit Name (eg, section) []:
→そのままEnterキー
Common Name (eg, your name or your server's hostname) []:
→ホスト名(ca1.free-style.biz)を入力します。(各自お好みで)
Email Address []:
→そのままEnterキー

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
→そのままEnterキー
An optional company name []:
→フレンドリ名(Fs DataCenter CA)を入力します。(各自お好みで)

---

「Netscape用」と言われていますが、クライアント用に必要なCA認証付きの署名リクエストを作成します。

作成はCAフォルダで実行します。
# cd /etc/pki/tls/misc
# openssl ca -policy policy_anything -out /usr/local/ssl/cert-ca.pem -infiles /usr/local/ssl/request.pem

---

Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for ../../CA/private/cakey.pem:
→CAの秘密鍵のパスフレーズを入力します。
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number: 5 (0x5)
Validity
Not Before: Jul 9 06:29:55 2010 GMT
Not After : Jul 8 06:29:55 2020 GMT
Subject:
countryName = JP
stateOrProvinceName = Tokyo
localityName = Shinagawa-ku
organizationName = Fs DataCenter CA
commonName = ca1.free-style.biz
X509v3 extensions:
X509v3 Basic Constraints:
CA:TRUE
Netscape Cert Type:
SSL Client, SSL Server, S/MIME, Object Signing
X509v3 Subject Key Identifier:
27:9F:05:BB:21:DC:E7:3A:86:04:22:04:70:B2:28:07:6B:66:19:00
X509v3 Authority Key Identifier:
keyid:AF:3D:E9:BC:17:83:29:D7:C0:4D:3F:E0:32:51:2C:BF:B1:B4:0A:00

Certificate is to be certified until Jul 8 06:29:55 2020 GMT (3652 days)
Sign the certificate? [y/n]:
→「証明書に署名しますか？」と聞かれるので、素直に「y」

1 out of 1 certificate requests certified, commit? [y/n]
→「署名リクエストを作成しますか？」と聞かれるのに、ここも素直に「y」
Write out database with 1 new entries
Data Base Updated

---

正常にサーバ証明書が作成されたか確認します。
CAの公開鍵と作成したサーバ証明書の指定はフルパスが確実です。
# openssl verify -CAfile /etc/pki/CA/cacert.pem /usr/local/ssl/cert-ca.pem
「/usr/local/ssl/cert-ca.pem: OK」と表示されれば正常に作成されています。

CA(認証局)の定義ファイルだけ作成して、おれおれCAを作成する方法もあるようですが、今回はローカルのデフォルトCAを入れ替える方法で作成します。

OS：CentOS5.3

1.オリジナルCAの定義ファイルをバックアップします。
# cd /etc/pki/tls
# cp -a openssl.cnf openssl.cnf.org

2.定義ファイルをおれおれCA用に変更します。
# vi openssl.cnf

---

#
# OpenSSL example configuration file.
# This is mostly being used for generation of certificate requests.
#

# This definition stops the following lines choking if HOME isn't
# defined.
HOME = .
RANDFILE = $ENV::HOME/.rnd

# Uncomment out to enable OpenSSL configuration see config(3)
# openssl_conf = openssl_init

# To use this configuration file with the "-extfile" option of the
# "openssl x509" utility, name here the section containing the
# X.509v3 extensions to use:
# extensions =
# (Alternatively, use a configuration file that has only
# X.509v3 extensions in its main [= default] section.)

[openssl_init]
# Extra OBJECT IDENTIFIER info:
oid_section = new_oids
alg_section = algs

[ new_oids ]

# We can add new OIDs in here for use by any config aware application
# Add a simple OID like this:
# shortname=Long Object Identifier Name, 1.2.3.4
# Or use config file substitution like this:
# testoid2=OID2 LONG NAME, ${testoid1}.5.6, OTHER OID

[ algs ]
# Algorithm configuration options. Currently just fips_mode
fips_mode = no

####################################################################
[ ca ]
default_ca = CA_default # The default ca section

####################################################################
[ CA_default ]

dir = ../../CA # Where everything is kept
certs = $dir/certs # Where the issued certs are kept
crl_dir = $dir/crl # Where the issued crl are kept
database = $dir/index.txt # database index file.
#unique_subject = no # Set to 'no' to allow creation of
# several ctificates with same subject.
new_certs_dir = $dir/newcerts # default place for new certs.

certificate = $dir/cacert.pem # The CA certificate
serial = $dir/serial # The current serial number
crlnumber = $dir/crlnumber # the current crl number
# must be commented out to leave a V1 CRL
crl = $dir/crl.pem # The current CRL
private_key = $dir/private/cakey.pem# The private key
RANDFILE = $dir/private/.rand # private random number file

x509_extensions = usr_cert # The extentions to add to the cert

# Comment out the following two lines for the "traditional"
# (and highly broken) format.
name_opt = ca_default # Subject Name options
cert_opt = ca_default # Certificate field options

# Extension copying option: use with caution.
# copy_extensions = copy

# Extensions to add to a CRL. Note: Netscape communicator chokes on V2 CRLs
# so this is commented out by default to leave a V1 CRL.
# crlnumber must also be commented out to leave a V1 CRL.
# crl_extensions = crl_ext

default_days = 365 # how long to certify for
→クライアント証明書の標準の有効期間を「3652」日(10年)に変更します。

default_crl_days= 30 # how long before next CRL
default_md = sha1 # which md to use.
preserve = no # keep passed DN ordering

# A few difference way of specifying how similar the request should look
# For type CA, the listed attributes must be the same, and the optional
# and supplied fields are just that :-)
policy = policy_match

# For the CA policy
[ policy_match ]
countryName = match
stateOrProvinceName = match
organizationName = match
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

# For the 'anything' policy
# At this point in time, you must list all acceptable 'object'
# types.
[ policy_anything ]
countryName = optional
stateOrProvinceName = optional
localityName = optional
organizationName = optional
organizationalUnitName = optional
commonName = supplied
emailAddress = optional

####################################################################
[ req ]
default_bits = 1024
→標準の公開鍵長を「2048」bitに変更します。

default_md = sha1
default_keyfile = privkey.pem
distinguished_name = req_distinguished_name
attributes = req_attributes
x509_extensions = v3_ca # The extentions to add to the self signed cert

# Passwords for private keys if not present they will be prompted for
# input_password = secret
# output_password = secret

# This sets a mask for permitted string types. There are several options.
# default: PrintableString, T61String, BMPString.
# pkix : PrintableString, BMPString.
# utf8only: only UTF8Strings.
# nombstr : PrintableString, T61String (no BMPStrings or UTF8Strings).
# MASK:XXXX a literal mask value.
# WARNING: current versions of Netscape crash on BMPStrings or UTF8Strings
# so use this option with caution!
# we use PrintableString+UTF8String mask so if pure ASCII texts are used
# the resulting certificates are compatible with Netscape
string_mask = MASK:0x2002

# req_extensions = v3_req # The extensions to add to a certificate request

[ req_distinguished_name ]
countryName = Country Name (2 letter code)
countryName_default = GB
→標準の国名を「JP」に変更します。

countryName_min = 2
countryName_max = 2

stateOrProvinceName = State or Province Name (full name)
stateOrProvinceName_default = Berkshire
→標準の都道府県名を「Tokyo」に変更します。(各自お好みで)

localityName = Locality Name (eg, city)
localityName_default = Newbury
→標準の都市名を「Shinagawa-ku」に変更します。(各自お好みで)

0.organizationName = Organization Name (eg, company)
0.organizationName_default = My Company Ltd
→標準の組織名を「Fs DataCenter CA」に変更します。(各自お好みで)

# we can do this but it is not needed normally :-)
#1.organizationName = Second Organization Name (eg, company)
#1.organizationName_default = World Wide Web Pty Ltd

organizationalUnitName = Organizational Unit Name (eg, section)
#organizationalUnitName_default =

commonName = Common Name (eg, your name or your server\'s hostname)
commonName_max = 64

emailAddress = Email Address
emailAddress_max = 64

# SET-ex3 = SET extension number 3

[ req_attributes ]
challengePassword = A challenge password
challengePassword_min = 4
challengePassword_max = 20

unstructuredName = An optional company name

[ usr_cert ]

# These extensions are added when 'ca' signs a request.

# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.

basicConstraints=CA:FALSE
→サーバ証明を「CA:TRUE」に変更します。

# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.

# This is OK for an SSL server.
# nsCertType = server

# For an object signing certificate this would be used.
# nsCertType = objsign

# For normal client use this is typical
# nsCertType = client, email

# and for everything including object signing:
# nsCertType = client, email, objsign
nsCertType = server, client, email, objsign
→サーバ証明の種類を追加します。「SSL サーバー認証」「SSL クライアント認証」「SMIME」「 署名」とりあえず全部入れます。

# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# This will be displayed in Netscape's comment listbox.
#nsComment = "OpenSSL Generated Certificate"
→コメントアウトします。

# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer

# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy
# An alternative to produce certificates that aren't
# deprecated according to PKIX.
# subjectAltName=email:move

# Copy subject details
# issuerAltName=issuer:copy

#nsCaRevocationUrl = http://www.domain.dom/ca-crl.pem
#nsBaseUrl
#nsRevocationUrl
#nsRenewalUrl
#nsCaPolicyUrl
#nsSslServerName

[ v3_req ]

# Extensions to add to a certificate request

basicConstraints = CA:FALSE
keyUsage = nonRepudiation, digitalSignature, keyEncipherment

[ v3_ca ]

# Extensions for a typical CA

# PKIX recommendation.

subjectKeyIdentifier=hash

authorityKeyIdentifier=keyid:always,issuer:always

# This is what PKIX recommends but some broken software chokes on critical
# extensions.
#basicConstraints = critical,CA:true
# So we do this instead.
basicConstraints = CA:true

# Key usage: this is typical for a CA certificate. However since it will
# prevent it being used as an test self-signed certificate it is best
# left out by default.
# keyUsage = cRLSign, keyCertSign

# Some might want this also
nsCertType = sslCA, emailCA
→コメントアウトを外します。

# Include email address in subject alt name: another PKIX recommendation
# subjectAltName=email:copy
# Copy issuer details
# issuerAltName=issuer:copy

# DER hex encoding of an extension: beware experts only!
# obj=DER:02:03
# Where 'obj' is a standard or added object
# You can even override a supported extension:
# basicConstraints= critical, DER:30:03:01:01:FF

[ crl_ext ]

# CRL extensions.
# Only issuerAltName and authorityKeyIdentifier make any sense in a CRL.

# issuerAltName=issuer:copy
authorityKeyIdentifier=keyid:always,issuer:always

[ proxy_cert_ext ]
# These extensions should be added when creating a proxy certificate

# This goes against PKIX guidelines but some CAs do it and some software
# requires this to avoid interpreting an end user certificate as a CA.

basicConstraints=CA:FALSE

# Here are some examples of the usage of nsCertType. If it is omitted
# the certificate can be used for anything *except* object signing.

# This is OK for an SSL server.
# nsCertType = server

# For an object signing certificate this would be used.
# nsCertType = objsign

# For normal client use this is typical
# nsCertType = client, email

# and for everything including object signing:
# nsCertType = client, email, objsign

# This is typical in keyUsage for a client certificate.
# keyUsage = nonRepudiation, digitalSignature, keyEncipherment

# This will be displayed in Netscape's comment listbox.
nsComment = "OpenSSL Generated Certificate"

# PKIX recommendations harmless if included in all certificates.
subjectKeyIdentifier=hash
authorityKeyIdentifier=keyid,issuer:always

# This stuff is for subjectAltName and issuerAltname.
# Import the email address.
# subjectAltName=email:copy
# An alternative to produce certificates that aren't
# deprecated according to PKIX.
# subjectAltName=email:move

# Copy subject details
# issuerAltName=issuer:copy

#nsCaRevocationUrl = http://www.domain.dom/ca-crl.pem
#nsBaseUrl
#nsRevocationUrl
#nsRenewalUrl
#nsCaPolicyUrl
#nsSslServerName

# This really needs to be in place for it to be a proxy certificate.
proxyCertInfo=critical,language:id-ppl-anyLanguage,pathlen:3,policy:foo

---

定義ファイルを保存します。

この定義ファイルを基にして新しいCAを構築します。

念のためオリジナルCAをバックアップします。
# cd /etc/pki
# mv CA CA.org
# cd /etc/pki/tls/misc/
# cp -a CA CA.org

設定ファイルを変更します。
# vi CA

---

DAYS="-days 365" # 1 year
→ルート証明書の有効期限を「DAYS="-days 3652" # 10 years」(10年)に変更します。
CADAYS="-days 1095" # 3 years
→CAの有効期限を「CADAYS="-days 3652" # 10 years」(10年)に変更します。

---

新しいCAを作成します。
# ./CA -newca

---

CA certificate filename (or enter to create)
→そのままEnterキー

Making CA certificate ...
Generating a 2048 bit RSA private key
.....................+++
....+++
writing new private key to '../../CA/private/./cakey.pem'
Enter PEM pass phrase:
→秘密鍵のパスワードを入力します。
Verifying - Enter PEM pass phrase:
→秘密鍵のパスワードを再入力します。
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [JP]:
→そのままEnterキー
State or Province Name (full name) [Tokyo]:
→そのままEnterキー
Locality Name (eg, city) [Shinagawa-ku]:
→そのままEnterキー
Organization Name (eg, company) [Otwo Co Ltd]:
→そのままEnterキー
Organizational Unit Name (eg, section) []:
→そのままEnterキー
Common Name (eg, your name or your server's hostname) []:
→CAのホスト名「ca1.free-style.biz」を入力します。(各自お好みで)
Email Address []:
→そのままEnterキー

Please enter the following 'extra' attributes
to be sent with your certificate request
A challenge password []:
→そのままEnterキー
An optional company name []:
→そのままEnterキー
Using configuration from /etc/pki/tls/openssl.cnf
Enter pass phrase for ../../CA/private/./cakey.pem:
→最後に最初に入力した秘密鍵を入力します。
Check that the request matches the signature
Signature ok
Certificate Details:
Serial Number: 0 (0x0)
Validity
Not Before: Jul 9 01:59:38 2010 GMT
Not After : Jul 8 01:59:38 2020 GMT
Subject:
countryName = JP
stateOrProvinceName = Tokyo
organizationName = Fs DataCenter CA
commonName = ca1.free-style.biz
X509v3 extensions:
X509v3 Basic Constraints:
CA:TRUE
Netscape Cert Type:
SSL Client, SSL Server, S/MIME, Object Signing
X509v3 Subject Key Identifier:
AF:3D:E9:BC:17:83:29:D7:C0:4D:3F:E0:32:51:2C:BF:B1:B4:0A:00
X509v3 Authority Key Identifier:
keyid:AF:3D:E9:BC:17:83:29:D7:C0:4D:3F:E0:32:51:2C:BF:B1:B4:0A:00

Certificate is to be certified until Jul 8 01:59:38 2020 GMT (3652 days)

Write out database with 1 new entries
Data Base Updated

---

オリジナルCAが完成しました。

ちょうど仕事の案件でS/MIMEを使用することになったので、調べてみました。

私自身はMyDocomoで送られてくるこの画面・・・

でおなじみのサイバートラストのS/MIME証明書「Sure Mail」を当てにしていたものの、問い合わせてみると、

「この商品は電子署名のみで暗号化していません」

なんですとーーーー！！！

確かに、電子署名と暗号化が同時に適用されたメールは

このようになります。（後で調べた結果ですが）

勝手に電子署名と暗号化が適用されていると思っていた自分がバカでしたが、単なるフィッシング対策だけのために大仰な仕組みを採用しているとは思ってもみなかった。

他のSSL証明書発行会社ではクライアントで使用するS/MIME証明書しか発行しておらず、今回サーバーからプログラムで実行するという条件では使えないものばかり。

やはりメール暗号化はマイナーな存在だ・・・・

結局、自己証明書で実現するしかなさそうだ！おれおれCA構築するぞ！