生成CA根证书

我们需要一个CA根证书(root)来为其它证书签名和认证,用户只需要安装这个根证书就能识别该根证书所签发的所有证书。以google网站为例,它的证书信任链如下:R1根证书签发了1C3证书,1C3又为www.google.com签发了证书。这里的根证书签发机构就相当于是一个公证处了,你需要向证书签发组织证明你对这个域名具有管理权,然后证书签发机构才会为你的域名或IP颁发证书,避免了假冒网站的问题。

img

像这样的权威机构的根证书是默认植入到我们的操作系统中并受信任的,所以浏览器能够通过根证书与证书信任链识别和验证该证书的真伪,从而提供安全可靠的端到端加密服务。

但是由于正规CA每年需要耗费大量的金钱来接受审计所的安全审计,所以有的公司的安全证书价格很贵,当然也有Let’s Encrypt这样的公益证书签发机构。我们也可以选择自己创建CA证书,自己给自己签发证书,但是需要手动在电脑上安装并信任这个CA证书,电脑才能识别。

进行下面的这些操作之前最好在当前目录下存放openssl.cnf,这个文件一般在系统中已经存在了,应该把它复制到当前的路径下,如果找不到的话可以手动创建并把代码写到里面,openssl.cnf的内容放在文章末尾。

生成CA证书的命令:

openssl genrsa -out ca.key 4096
openssl req -x509 -new -nodes -key ca.key -subj "/CN=hash070" -days 3650 -out ca.crt

第一行是利用openssl随机生成一个key

第二行是利用上面随机生成的key来生成证书文件

利用根证书签发SAN证书 (RSA)

首先随机生成一个key

openssl genrsa -out server.key 2048

然后生成证书认证签名请求(Certificate signing request)

openssl req -new -sha256 -key server.key \
    -subj "/C=CN/ST=DEFAULT/L=DEFAULT/O=DEFAULT/CN=hash070.top" \
    -reqexts SAN \
    -config <(cat openssl.cnf <(printf "\n[SAN]\nsubjectAltName=DNS:hash070.top,IP:127.0.0.1,DNS:*.hash070.top")) \
    -out server.csr

注:

  • CN=hash070.top指的是该证书的名称
  • subjectAltName=后面写上该证书所保护的域名或IP

最后用CA证书+CA密钥+签名请求来签发证书

openssl x509 -req -days 365 \
    -in server.csr -CA ca.crt -CAkey ca.key -CAcreateserial \
    -extfile <(printf "subjectAltName=DNS:hash070.top,IP:127.0.0.1,DNS:*.hash070.top") \
    -out server.crt

注:

  • -days指的是证书有效期,如果该证书用于https的话最好只签1年以下的,否则浏览器仍然会报不信任。

自签名证书签发流程:

生成随机密钥(key)>使用密钥生成签名请求(csr)>使用CA密钥和CA证书来批准证书签名请求,最终获得证书

签署ECC证书(推荐)

ECC证书密钥更短,更难以破解,速度更快,总之全方面吊打RSA,推荐逐步使用ECC替代RSA证书,例如本小破站就在使用ECC证书,同时也配置了RSA证书以防较久的客户端不支持。

签发流程总体和RSA证书一样

选择椭圆曲线

openssl ecparam -list_curves

执行该命令后,会列出一堆曲线

1661757477389.png

其中比较常用的就是prime256v1secp521r1,前者是广泛被各大CA使用的ECC曲线,比如用prime256v1签出来的证书显示的算法为ECDSA_P256

生成椭圆密钥

openssl ecparam -name secp521r1 -genkey -out myECC.key

生成ECC密钥的CSR申请书

openssl req -new -sha256 -key myECC.key \
    -subj "/C=CN/ST=DEFAULT/L=DEFAULT/O=DEFAULT/CN=DigiCert" \
    -reqexts SAN \
    -config <(cat openssl.cnf <(printf "\n[SAN]\nsubjectAltName=DNS:yourdomain.top,IP:127.0.0.1,DNS:*.yourdomain.top")) \
    -out myECC.csr

用CA证书为CSR盖章,生成证书

openssl x509 -req -days 365 \
    -in myECC.csr -CA ca.crt -CAkey ca.key -CAcreateserial \
    -extfile <(printf "subjectAltName=DNS:yourdomain.top,IP:127.0.0.1,DNS:*.yourdomain.top") \
    -out hash070TLS.crt

生成结果

1661757744663.png

openssl.cnf文件内容

#
# 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

# Extra OBJECT IDENTIFIER info:
#oid_file        = $ENV::HOME/.oid
oid_section        = new_oids

# 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.)

[ new_oids ]

# We can add new OIDs in here for use by 'ca', 'req' and 'ts'.
# Add a simple OID like this:
# testoid1=1.2.3.4
# Or use config file substitution like this:
# testoid2=${testoid1}.5.6

# Policies used by the TSA examples.
tsa_policy1 = 1.2.3.4.1
tsa_policy2 = 1.2.3.4.5.6
tsa_policy3 = 1.2.3.4.5.7

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

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

dir        = ./demoCA        # 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
default_crl_days= 30            # how long before next CRL
default_md    = default        # use public key default MD
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        = 2048
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 (PKIX recommendation before 2004)
# utf8only: only UTF8Strings (PKIX recommendation after 2004).
# nombstr : PrintableString, T61String (no BMPStrings or UTF8Strings).
# MASK:XXXX a literal mask value.
# WARNING: ancient versions of Netscape crash on BMPStrings or UTF8Strings.
string_mask = utf8only

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

[ req_distinguished_name ]
countryName            = Country Name (2 letter code)
countryName_default        = AU
countryName_min            = 2
countryName_max            = 2

stateOrProvinceName        = State or Province Name (full name)
stateOrProvinceName_default    = Some-State

localityName            = Locality Name (eg, city)

0.organizationName        = Organization Name (eg, company)
0.organizationName_default    = Internet Widgits Pty Ltd

# 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 (e.g. server FQDN or YOUR name)
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

# 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

# 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 is required for TSA certificates.
# extendedKeyUsage = critical,timeStamping

[ 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

# 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

# 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

[ 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

# 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

####################################################################
[ tsa ]

default_tsa = tsa_config1    # the default TSA section

[ tsa_config1 ]

# These are used by the TSA reply generation only.
dir        = ./demoCA        # TSA root directory
serial        = $dir/tsaserial    # The current serial number (mandatory)
crypto_device    = builtin        # OpenSSL engine to use for signing
signer_cert    = $dir/tsacert.pem     # The TSA signing certificate
                    # (optional)
certs        = $dir/cacert.pem    # Certificate chain to include in reply
                    # (optional)
signer_key    = $dir/private/tsakey.pem # The TSA private key (optional)

default_policy    = tsa_policy1        # Policy if request did not specify it
                    # (optional)
other_policies    = tsa_policy2, tsa_policy3    # acceptable policies (optional)
digests        = md5, sha1        # Acceptable message digests (mandatory)
accuracy    = secs:1, millisecs:500, microsecs:100    # (optional)
clock_precision_digits  = 0    # number of digits after dot. (optional)
ordering        = yes    # Is ordering defined for timestamps?
                # (optional, default: no)
tsa_name        = yes    # Must the TSA name be included in the reply?
                # (optional, default: no)
ess_cert_id_chain    = no    # Must the ESS cert id chain be included?
                # (optional, default: no)

Q.E.D.