固若金汤 - PostgreSQL pgcrypto加密插件

背景

默认情况下数据都是以明文存储在数据库中的。

如果未使用数据传输层加密手段的话, 数据一旦在传输中被截获的话就很容易泄漏数据。

本文将要介绍的是数据内容的加密。

数据内容的加密可以在数据库服务端进行加解密, 也可以在客户端进行加解密.

在数据库服务端加解密的话, 网络上传输的还是未加密的内容, 所以为了防御网络数据截获, 建议还是要搭配使用数据传输加密.

如果是在客户端进行加解密的话, 网络上传输的是加密后的内容, 所以不必担心网络数据截获的问题.

下面以pgcrypto这个扩展包为例, 讲一下数据库服务端加密.

PostgreSQL 加密插件pgcrypto的用法

阿里云正在将这个插件整合到正在公测的ApsaraDB for Greenplum数据库，如果你在RDS PG中使用了这个插件，恭喜你，可以平移到Greenplum了。

数据仓库是企业数据的集散地，数据安全不容忽视，特别是云上的用户更是如此。

https://www.aliyun.com/product/gpdb?spm=5176.7960203.237031.39.3aCwlI

创建pgcrypto扩展包

pg92@db-172-16-3-40-> psql -h 172.16.3.33 -p 1999 -U postgres digoal
psql (9.2beta1, server 9.3devel)
WARNING: psql version 9.2, server version 9.3.
         Some psql features might not work.
SSL connection (cipher: RC4-SHA, bits: 128)
Type "help" for help.
digoal=# create extension pgcrypto;
CREATE EXTENSION

pgcrypto包含了一些加密和解密的函数.
详见PostgreSQL手册.

下面主要针对新增的加解密函数进行讲解.

计算hash值的函数

digest(data text, type text) returns bytea
digest(data bytea, type text) returns bytea

type为算法.支持 md5, sha1, sha224, sha256, sha384, sha512. 如果编译postgresql时时有了with-openssl选项, 则可以支持更多的算法.

例如 :

digoal=# select digest('I am digoal.', 'md5');
               digest               
------------------------------------
 \xc3b0fb1147858d2259d92f20668fc8f9
(1 row)

每次运算得到的hash值都一样.

digoal=# select digest('I am digoal.', 'md5');
               digest               
------------------------------------
 \xc3b0fb1147858d2259d92f20668fc8f9
(1 row)

但是请注意函数参数, 如果要对bytea hash, 那么请在输入参数时指定参数类型bytea.

例如以下两次调用分别调用了2个函数. 所以得到的结果也是不一样的.

digoal=# select digest('\xffffff'::bytea, 'md5');
               digest               
------------------------------------
 \x8597d4e7e65352a302b63e07bc01a7da
(1 row)
digoal=# select digest('\xffffff', 'md5');
               digest               
------------------------------------
 \xd721f40e22920e0fd8ac7b13587aa92d
(1 row)

hmac(data text, key text, type text) returns bytea
hmac(data bytea, key text, type text) returns bytea

这两个函数与digest类似, 只是多了一个key参数, 也就是说同一个被加密的值, 可以使用不同的key得到不同的hash值.

这样的做法是, 不知道key的话, 也无法逆向破解原始值.

使用hmac还有一个好处是, 使用digest如果原始值和hash值同时被别人修改了是无法知道是否被修改的.

但是使用hmac, 如果原始值被修改了, 同时key没有泄漏的话, 那么hash值是无法被修改的, 因此就能够知道原始值是否被修改过.

digoal=# select hmac('I am digoal.', 'this is a key', 'md5');
                hmac                
------------------------------------
 \xc70d0fd2af2382ea8e0a7ffd9edcbd58
(1 row)
digoal=# select hmac('I am digoal.', 'this is a key', 'md5');
                hmac                
------------------------------------
 \xc70d0fd2af2382ea8e0a7ffd9edcbd58
(1 row)
digoal=# select hmac('I am digoal.', 'this is b key', 'md5');
                hmac                
------------------------------------
 \x4518090fb07fc672b66c829e43fd62dc
(1 row)
digoal=# select hmac('I am digoal.', 'this is b key', 'md5');
                hmac                
------------------------------------
 \x4518090fb07fc672b66c829e43fd62dc
(1 row)

如果key的长度超过了block size, 那么key会先hash一次, 然后hash值作为key.

以上hash函数只要原始值一致, 每次得到的hash值是一样的, 虽然hmac多了key的参数, 但是只要key和原始数据一样, 得到的hash值也是一样的. 这样的加密很可能被逆向破解掉.

如何加大破解难度

下面的2个函数主要是提高了逆向破解的难度, 增强了数据的安全性.

crypt(password text, salt text) returns text
gen_salt(type text [, iter_count integer ]) returns text

crypt(), 用来计算hash值.

gen_salt(), 用来产生随机的参数给crypt. type参数为des, xdes, md5, bf. iter_count指迭代次数, 数字越大加密时间越长, 被破解需要的时间也越长.

Table F-16. Iteration Counts for crypt()

xdes的iter_count必须为奇数.

crypt和gen_salt结合使用的话, 同一个原始值, 每次得到的hash值是不一样的.

digoal=# select crypt('this is a pwd source', gen_salt('md5'));
               crypt                
------------------------------------
 $1$CAp4ifAa$p261Vfku7HDnwx8cuFhsq/
(1 row)
digoal=# select crypt('this is a pwd source', gen_salt('bf',10));
                            crypt                             
--------------------------------------------------------------
 $2a$10$tvNK2H9mPu1tU5L6oAHdSeze5Hlz7G0y4oEKNg9SlGa06J2sywZHu
(1 row)

# 每次运算可以得到不同的hash值.

digoal=# select crypt('this is a pwd source', gen_salt('md5'));
               crypt                
------------------------------------
 $1$p2Sg93iZ$SCdUePtZVuyIJBDO1cEYh1
(1 row)
digoal=# select crypt('this is a pwd source', gen_salt('bf',10));
                            crypt                             
--------------------------------------------------------------
 $2a$10$cgJiTAs55vMBqYR1kGMGXuMKZI4dsayna4wgEL4K7duYkD0g25ufW
(1 row)

原因是gen_salt每次都会给出1个随机值.

digoal=# select gen_salt('bf',10);
           gen_salt            
-------------------------------
 $2a$10$qY0amXGalzj14rooSpTf5e
(1 row)
digoal=# select gen_salt('bf',10);
           gen_salt            
-------------------------------
 $2a$10$TmqxqmOd8R3scnPk25Pp2O
(1 row)

计算好hash后匹配是怎么做的呢?

看下面, hash值作为第二个参数, 得到的值就是hash值. 所以这样就可以进行匹配了.

digoal=# select crypt('this is a pwd source', gen_salt('bf',10));
                            crypt                             
--------------------------------------------------------------
 $2a$10$x5bQ0wcHc0.li1XcDbzSyOvpjPOKlzg.psbNaA33VH.gAfKbA7.IK
(1 row)
digoal=# select crypt('this is a pwd source', gen_salt('bf',10));
                            crypt                             
--------------------------------------------------------------
 $2a$10$X7D5eMxcaXNn.BPkPnb1GuSVxDUjNiO5M/9ss9GLHpgGq6s3hbPrG
(1 row)
digoal=# select crypt('this is a pwd source', '$2a$10$X7D5eMxcaXNn.BPkPnb1GuSVxDUjNiO5M/9ss9GLHpgGq6s3hbPrG');
                            crypt                             
--------------------------------------------------------------
 $2a$10$X7D5eMxcaXNn.BPkPnb1GuSVxDUjNiO5M/9ss9GLHpgGq6s3hbPrG
(1 row)
digoal=# select crypt('this is a pwd source', '$2a$10$x5bQ0wcHc0.li1XcDbzSyOvpjPOKlzg.psbNaA33VH.gAfKbA7.IK');
                            crypt                             
--------------------------------------------------------------
 $2a$10$x5bQ0wcHc0.li1XcDbzSyOvpjPOKlzg.psbNaA33VH.gAfKbA7.IK
(1 row)

假设用它来存密码 :

digoal=# create table userpwd(userid int8 primary key, pwd text);
CREATE TABLE
digoal=# insert into userpwd (userid,pwd) values (1, crypt('this is a pwd source', gen_salt('bf',10)));
INSERT 0 1

输入错误的密码, 返回假

digoal=# select crypt('this is a error pwd source', pwd)=pwd from userpwd where userid =1;
 ?column? 
----------
 f
(1 row)

输入正确的密码, 返回真

digoal=# select crypt('this is a pwd source', pwd)=pwd from userpwd where userid =1;
 ?column? 
----------
 t
(1 row)

crypt支持的算法如下 :

Table F-15. Supported Algorithms for crypt()

当然, crypt和gen_salt是以牺牲hash速度为代价来换取安全性的.

以上hash计算速度取自1.5G的奔腾4 CPU. 以及如下测试软件 :

crypt-des and crypt-md5 algorithm numbers are taken from John the Ripper v1.6.38 -test output.
md5 numbers are from mdcrack 1.2.
sha1 numbers are from lcrack-20031130-beta.
crypt-bf numbers are taken using a simple program that loops over 1000 8-character passwords. 
That way I can show the speed with different numbers of iterations. 
For reference: john -test shows 213 loops/sec for crypt-bf/5. 
(The very small difference in results is in accordance with the fact that the crypt-bf implementation in pgcrypto is the same one used in John the Ripper.)

原则上, iter_count的选择以hash计算速度为准则, 以当前流行的CPU, 并且实测后取4-100每秒之间为宜.

PGP 加密函数

PostgreSQL pgcrypto扩展包中的pgp加解密函数遵循OpenPGP (RFC 4880)标准.

加密的PGP消息由2部分组成 :

• 这个消息的会话密钥, 会话密钥可以是对称密钥或公钥.
• 使用该会话密钥加密的数据, 可以选择加密选项例如

compress-algo, unicode-mode, cipher-algo, compress-level, convert-crlf, disable-mdc, enable-session-key, s2k-mode, s2k-digest-algo, s2k-cipher-algo

使用对称密钥加解密的函数如下 :

pgp_sym_encrypt(data text, psw text [, options text ]) returns bytea
pgp_sym_encrypt_bytea(data bytea, psw text [, options text ]) returns bytea
pgp_sym_decrypt(msg bytea, psw text [, options text ]) returns text
pgp_sym_decrypt_bytea(msg bytea, psw text [, options text ]) returns bytea

options参考pgcrypto加密选项部分.

PGP 对称加密举例

使用对称密钥加密, 这里的对称密钥为'pwd'字符串 :

digoal=# select pgp_sym_encrypt('i am digoal', 'pwd', 'cipher-algo=bf, compress-algo=2, compress-level=9');
                                                                          pgp_sym_encrypt                                           
                                
------------------------------------------------------------------------------------------------------------------------------------
--------------------------------
 \xc30d0404030245811e051118cc136ed23f0198808f069b53264d4a08c2b5dcf3b1c39a34d091263f7f6b64a14808e6ffb32ccc09749105b9cc062d70c628357ab
1e2474ff6d109dd083ce892cfa55706
(1 row)

解密也需要使用加密时的对称密钥 :

digoal=# select pgp_sym_decrypt('\xc30d0404030245811e051118cc136ed23f0198808f069b53264d4a08c2b5dcf3b1c39a34d091263f7f6b64a14808e6ffb32ccc09749105b9cc062d70c628357ab1e2474ff6d109dd083ce892cfa55706'::bytea, 'pwd');
 pgp_sym_decrypt 
-----------------
 i am digoal
(1 row)

使用公钥加解密的函数

pgp_pub_encrypt(data text, key bytea [, options text ]) returns bytea
pgp_pub_encrypt_bytea(data bytea, key bytea [, options text ]) returns bytea
pgp_pub_decrypt(msg bytea, key bytea [, psw text [, options text ]]) returns text
pgp_pub_decrypt_bytea(msg bytea, key bytea [, psw text [, options text ]]) returns bytea

options参考pgcrypto加密选项部分.

公钥加密举例 :

首先要使用gpg生成一对公钥和密钥. 当然你也可以生成很多对.

加密用公钥, 解密用对应的私钥即可.

公钥和私钥都可以放在客户端, 这样的话数据库中只存储加密后的数据, 攻击者获取数据后也无法对它进行解密.

生成一对公钥密钥

pg92@db-172-16-3-40-> gpg --gen-key
gpg (GnuPG) 1.4.5; Copyright (C) 2006 Free Software Foundation, Inc.
This program comes with ABSOLUTELY NO WARRANTY.
This is free software, and you are welcome to redistribute it
under certain conditions. See the file COPYING for details.

Please select what kind of key you want:
   (1) DSA and Elgamal (default)
   (2) DSA (sign only)
   (5) RSA (sign only)
Your selection? 1  #选择1
DSA keypair will have 1024 bits.
ELG-E keys may be between 1024 and 4096 bits long.
What keysize do you want? (2048) #选择2048
Requested keysize is 2048 bits
Please specify how long the key should be valid.
         0 = key does not expire
      <n>  = key expires in n days
      <n>w = key expires in n weeks
      <n>m = key expires in n months
      <n>y = key expires in n years
Key is valid for? (0) #选择0, 永不过期.
Key does not expire at all
Is this correct? (y/N) y #输入y

You need a user ID to identify your key; the software constructs the user ID
from the Real Name, Comment and Email Address in this form:
    "Heinrich Heine (Der Dichter) <heinrichh@duesseldorf.de>"

Real name: digoal  # 必须输入的是name, 后面要用到这个name导出公钥和密钥.
Email address: 
Comment: 
You selected this USER-ID:
    "digoal"

Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? O  # 输入O确认
You need a Passphrase to protect your secret key.
# 这里可以选择输入保护密钥的passphrase, 当然也可以不输入留空. 
# 如果输入了, 那么使用pgp_pub_decrypt函数解密数据时则需要输入这个 passphrase.
# 本例不输入passphrase.
You don't want a passphrase - this is probably a *bad* idea!
I will do it anyway.  You can change your passphrase at any time,
using this program with the option "--edit-key".
# 马上在另一个会话中执行ll -R /. 这样可以让服务器产生一些动作. 否则可能造成如下错误 : 
# Not enough random bytes available.  Please do some other work to give
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
+++++++++++++++.++++++++++.++++++++++..++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++.+++++.+++++.+++++.++++++++++++++++++++>.++++++++++....>+++++............<+++++............+++++
We need to generate a lot of random bytes. It is a good idea to perform
some other action (type on the keyboard, move the mouse, utilize the
disks) during the prime generation; this gives the random number
generator a better chance to gain enough entropy.
++++++++++++++++++++.+++++..+++++...+++++.+++++.++++++++++.++++++++++++++++++++..+++++.+++++.++++++++++..+++++++++++++++++++++++++.+++++++++++++++.++++++++++.+++++>.+++++.+++++>+++++.>+++++>+++++<+++++....+++++^^^
gpg: key 634F912F marked as ultimately trusted
public and secret key created and signed.

gpg: checking the trustdb
gpg: 3 marginal(s) needed, 1 complete(s) needed, PGP trust model
gpg: depth: 0  valid:   1  signed:   0  trust: 0-, 0q, 0n, 0m, 0f, 1u
pub   1024D/634F912F 2013-05-25
      Key fingerprint = D2CD D9B8 F1C3 D940 33E9  9E94 DA32 0B23 634F 912F
uid                  digoal
sub   2048g/D670D845 2013-05-25

#　接下来要生成公钥和密钥

# 列出当前系统中的钥匙串

pg92@db-172-16-3-40-> gpg --list-secret-keys
/home/pg92/.gnupg/secring.gpg
-----------------------------
sec   1024D/634F912F 2013-05-25
uid                  digoal
ssb   2048g/D670D845 2013-05-25

# 导出uid=digoal的公钥

pg92@db-172-16-3-40-> gpg -a --export digoal > public.key

# 导出uid=digoal的密钥

pg92@db-172-16-3-40-> gpg -a --export-secret-keys digoal > secret.key

# 查看公钥和密钥内容
公钥内容 :

pg92@db-172-16-3-40-> cat public.key 
-----BEGIN PGP PUBLIC KEY BLOCK-----
Version: GnuPG v1.4.5 (GNU/Linux)
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=XGEV
-----END PGP PUBLIC KEY BLOCK-----

私钥内容 :

pg92@db-172-16-3-40-> cat secret.key 
-----BEGIN PGP PRIVATE KEY BLOCK-----
Version: GnuPG v1.4.5 (GNU/Linux)
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=FwrW
-----END PGP PRIVATE KEY BLOCK-----

# 使用公钥加密数据, 使用私钥解密数据时,

# pgcrypto 需要字节流数据.

# 所以在使用公钥和私钥前请先把他们转换为bytea.

转换公钥为bytea :

digoal=# select dearmor('-----BEGIN PGP PUBLIC KEY BLOCK-----
digoal'# Version: GnuPG v1.4.5 (GNU/Linux)
digoal'# 
digoal'# mQGiBFGgIDgRBADALXrWA4PyT+Mj6be2Jl0kMeXItZqdqOp5fKOYNpWT2LqKBa9Y
digoal'# RFMDZHSS1MIfjyDEi07O+TKm98haHBowbHB00qMXW6z6VAxtqdUBt9b0L52OwkA9
digoal'# awsclpalPvLwDAQGpxlJh7aQJ0hHjQRgvfTqJpOoCF4WoMVVSin5Ox2P4wCgzcr7
digoal'# FtLhbysH/Axqmx6Oc3wG3FMD/ij4ES38IDNAoacCOuWlA6MeaxWzgVka1Zl/h2kt
digoal'# UVJOLeM0saF6Z570/RYYFASC5cVazCG9Gbq6a3WvCy6LW9hV5XZIOU1VBXYxaCP1
digoal'# sMeWgRSbVathdJMqbcz+kzqabiCVHDt5Q8k/TuIEvmkTnUbk1ca1GTxRJMhXYldZ
digoal'# LDAcA/4hnPbjxUUtkQ9S6gP3Cih/8SOA/E4YIj5PK3S9nRc6OKZ9NiGVXmhqff8P
digoal'# A4TmX08DiVclDzsaxpmB1yYUc44/rhEZ53XxKfHzjvowNKEevBm+cPEc0U9a5VSF
digoal'# IBwfwuAAVbbfdmLKM+HcBsPc/3uRnNGRZX6mMvUAG9UCk50zUrQGZGlnb2FsiGAE
digoal'# ExECACAFAlGgIDgCGwMGCwkIBwMCBBUCCAMEFgIDAQIeAQIXgAAKCRDaMgsjY0+R
digoal'# L6mpAJ97/he5t1uatNKyO5v00bfuq9hMrQCgyihwLNzCn3immQp1E8fsg0Rfmaq5
digoal'# Ag0EUaAgORAIAPf4AB8dn2tYQlqOu3cC4g+yD95RV+lxERWLwMNzH1aVuSmBQzZA
digoal'# 7pZuAyt9Joy6kwgkcilWtP1XgwUQBnyfS5QOiqNAbDoKFZWxLVKPpvb8jk20zbiW
digoal'# vqH9IUVlMaRjJrY1kdC1ckPFmx17k4uFU9GKFrfx/VukaTBhK3iByUD4JGUvmqKJ
digoal'# vu3DX3JliIH4PJaBFxp/nOIy/66gPPz2DkSTBBNYTNVtMqkDLz2gcAWQ99TWsEXR
digoal'# skehPk9FSUDvrs62vC7ZsGmwihSMt/B/gQHc9rmEs5RkqNfyYKUoI4d5UCQdWnjI
digoal'# +V5Sppq6HQhRJ9M0ytoqmYJDKioKR0ewBQMAAwUH/jOZn7ei1rZLv0RP0Y+/E0RO
digoal'# kzpNmMuP+mNvZNrf/PCd1SvPxFZ2MNnhB0JN9a1OjJD8otqqvxMujyTx5z0RqD+7
digoal'# mWKb/q96NpG+fApZNGt6YiTc4a9FV9jpf+fYZyfpOj/bmPpHIUtheGzx/+WIL9gH
digoal'# WDiFR0nP9uXZoDZotuPqEsH2acoIE4oB4lLBvajuDtwnAZlajHMgXZD9W/xzdAlR
digoal'# 5frfGNVIdvylwN2SOfSavl4VM4hG1uFc2J4szmivK0TesP1UcIdxnTlTvFieEqaP
digoal'# 2rpG6WfVVO7N5ZiWXYOuazzRSEtfTjnGZRnx+WmkUb5KNvVhSg8F7oB7WrKMH/2I
digoal'# SQQYEQIACQUCUaAgOQIbDAAKCRDaMgsjY0+RLx/TAJ4uAleVExWDEVSbNeqm9wBk
digoal'# gRNGbgCeK648ARQH8pBNHcX/hsefvah7TO4=
digoal'# =XGEV
digoal'# -----END PGP PUBLIC KEY BLOCK-----');

得到

\x9901a20451a02038110400c02d7ad60383f24fe323e9b7b6265d2431e5c8b59a9da8ea797ca398369593d8ba8a05af58445303647492d4c21f8f20c48b4ecef93
2a6f7c85a1c1a306c7074d2a3175bacfa540c6da9d501b7d6f42f9d8ec2403d6b0b1c9696a53ef2f00c0406a7194987b6902748478d0460bdf4ea2693a8085e16a0c
5554a29f93b1d8fe300a0cdcafb16d2e16f2b07fc0c6a9b1e8e737c06dc5303fe28f8112dfc203340a1a7023ae5a503a31e6b15b381591ad5997f87692d51524e2de
334b1a17a679ef4fd1618140482e5c55acc21bd19baba6b75af0b2e8b5bd855e57648394d550576316823f5b0c79681149b55ab6174932a6dccfe933a9a6e20951c3
b7943c93f4ee204be69139d46e4d5c6b5193c5124c8576257592c301c03fe219cf6e3c5452d910f52ea03f70a287ff12380fc4e18223e4f2b74bd9d173a38a67d362
1955e686a7dff0f0384e65f4f038957250f3b1ac69981d72614738e3fae1119e775f129f1f38efa3034a11ebc19be70f11cd14f5ae55485201c1fc2e00055b6df766
2ca33e1dc06c3dcff7b919cd191657ea632f5001bd502939d3352b4066469676f616c8860041311020020050251a02038021b03060b0908070302041502080304160
20301021e01021780000a0910da320b23634f912fa9a9009f7bfe17b9b75b9ab4d2b23b9bf4d1b7eeabd84cad00a0ca28702cdcc29f78a6990a7513c7ec83445f99a
ab9020d0451a02039100800f7f8001f1d9f6b58425a8ebb7702e20fb20fde5157e97111158bc0c3731f5695b92981433640ee966e032b7d268cba930824722956b4f
d57830510067c9f4b940e8aa3406c3a0a1595b12d528fa6f6fc8e4db4cdb896bea1fd21456531a46326b63591d0b57243c59b1d7b938b8553d18a16b7f1fd5ba4693
0612b7881c940f824652f9aa289beedc35f72658881f83c9681171a7f9ce232ffaea03cfcf60e44930413584cd56d32a9032f3da0700590f7d4d6b045d1b247a13e4
f454940efaeceb6bc2ed9b069b08a148cb7f07f8101dcf6b984b39464a8d7f260a52823877950241d5a78c8f95e52a69aba1d085127d334cada2a9982432a2a0a474
7b0050300030507fe33999fb7a2d6b64bbf444fd18fbf13444e933a4d98cb8ffa636f64dadffcf09dd52bcfc4567630d9e107424df5ad4e8c90fca2daaabf132e8f2
4f1e73d11a83fbb99629bfeaf7a3691be7c0a59346b7a6224dce1af4557d8e97fe7d86727e93a3fdb98fa47214b61786cf1ffe5882fd8075838854749cff6e5d9a03
668b6e3ea12c1f669ca08138a01e252c1bda8ee0edc2701995a8c73205d90fd5bfc73740951e5fadf18d54876fca5c0dd9239f49abe5e15338846d6e15cd89e2cce6
8af2b44deb0fd547087719d3953bc589e12a68fdaba46e967d554eecde598965d83ae6b3cd1484b5f4e39c66519f1f969a451be4a36f5614a0f05ee807b5ab28c1ff
d8849041811020009050251a02039021b0c000a0910da320b23634f912f1fd3009e2e02579513158311549b35eaa6f700648113466e009e2bae3c011407f2904d1dc
5ff86c79fbda87b4cee

转换私钥为bytea :

digoal=# select dearmor('-----BEGIN PGP PRIVATE KEY BLOCK-----
digoal'# Version: GnuPG v1.4.5 (GNU/Linux)
digoal'# 
digoal'# lQG7BFGgIDgRBADALXrWA4PyT+Mj6be2Jl0kMeXItZqdqOp5fKOYNpWT2LqKBa9Y
digoal'# RFMDZHSS1MIfjyDEi07O+TKm98haHBowbHB00qMXW6z6VAxtqdUBt9b0L52OwkA9
digoal'# awsclpalPvLwDAQGpxlJh7aQJ0hHjQRgvfTqJpOoCF4WoMVVSin5Ox2P4wCgzcr7
digoal'# FtLhbysH/Axqmx6Oc3wG3FMD/ij4ES38IDNAoacCOuWlA6MeaxWzgVka1Zl/h2kt
digoal'# UVJOLeM0saF6Z570/RYYFASC5cVazCG9Gbq6a3WvCy6LW9hV5XZIOU1VBXYxaCP1
digoal'# sMeWgRSbVathdJMqbcz+kzqabiCVHDt5Q8k/TuIEvmkTnUbk1ca1GTxRJMhXYldZ
digoal'# LDAcA/4hnPbjxUUtkQ9S6gP3Cih/8SOA/E4YIj5PK3S9nRc6OKZ9NiGVXmhqff8P
digoal'# A4TmX08DiVclDzsaxpmB1yYUc44/rhEZ53XxKfHzjvowNKEevBm+cPEc0U9a5VSF
digoal'# IBwfwuAAVbbfdmLKM+HcBsPc/3uRnNGRZX6mMvUAG9UCk50zUgAAn2j3pAZqpbN3
digoal'# xfFFL2YYhP+ePmrnCzm0BmRpZ29hbIhgBBMRAgAgBQJRoCA4AhsDBgsJCAcDAgQV
digoal'# AggDBBYCAwECHgECF4AACgkQ2jILI2NPkS+pqQCfe/4XubdbmrTSsjub9NG37qvY
digoal'# TK0AoMoocCzcwp94ppkKdRPH7INEX5mqnQI9BFGgIDkQCAD3+AAfHZ9rWEJajrt3
digoal'# AuIPsg/eUVfpcREVi8DDcx9WlbkpgUM2QO6WbgMrfSaMupMIJHIpVrT9V4MFEAZ8
digoal'# n0uUDoqjQGw6ChWVsS1Sj6b2/I5NtM24lr6h/SFFZTGkYya2NZHQtXJDxZsde5OL
digoal'# hVPRiha38f1bpGkwYSt4gclA+CRlL5qiib7tw19yZYiB+DyWgRcaf5ziMv+uoDz8
digoal'# 9g5EkwQTWEzVbTKpAy89oHAFkPfU1rBF0bJHoT5PRUlA767Otrwu2bBpsIoUjLfw
digoal'# f4EB3Pa5hLOUZKjX8mClKCOHeVAkHVp4yPleUqaauh0IUSfTNMraKpmCQyoqCkdH
digoal'# sAUDAAMFB/4zmZ+3ota2S79ET9GPvxNETpM6TZjLj/pjb2Ta3/zwndUrz8RWdjDZ
digoal'# 4QdCTfWtToyQ/KLaqr8TLo8k8ec9Eag/u5lim/6vejaRvnwKWTRremIk3OGvRVfY
digoal'# 6X/n2Gcn6To/25j6RyFLYXhs8f/liC/YB1g4hUdJz/bl2aA2aLbj6hLB9mnKCBOK
digoal'# AeJSwb2o7g7cJwGZWoxzIF2Q/Vv8c3QJUeX63xjVSHb8pcDdkjn0mr5eFTOIRtbh
digoal'# XNieLM5orytE3rD9VHCHcZ05U7xYnhKmj9q6Ruln1VTuzeWYll2Drms80UhLX045
digoal'# xmUZ8flppFG+Sjb1YUoPBe6Ae1qyjB/9AAFUCNmPaOMHsDg6bZpo7ApZJbJsiW6Z
digoal'# BTCojWYF4E2C+5bPQoietziIE5V6LhPdiEkEGBECAAkFAlGgIDkCGwwACgkQ2jIL
digoal'# I2NPkS8f0wCgpSCnhRw+soY+Fpg5t7IHjusqNt0An0EeMye7x5uyQc2ikmVtgfZu
digoal'# NOxi
digoal'# =FwrW
digoal'# -----END PGP PRIVATE KEY BLOCK-----');

得到 :

\x9501bb0451a02038110400c02d7ad60383f24fe323e9b7b6265d2431e5c8b59a9da8ea797ca398369593d8ba8a05af58445303647492d4c21f8f20c48b4ecef93
2a6f7c85a1c1a306c7074d2a3175bacfa540c6da9d501b7d6f42f9d8ec2403d6b0b1c9696a53ef2f00c0406a7194987b6902748478d0460bdf4ea2693a8085e16a0c
5554a29f93b1d8fe300a0cdcafb16d2e16f2b07fc0c6a9b1e8e737c06dc5303fe28f8112dfc203340a1a7023ae5a503a31e6b15b381591ad5997f87692d51524e2de
334b1a17a679ef4fd1618140482e5c55acc21bd19baba6b75af0b2e8b5bd855e57648394d550576316823f5b0c79681149b55ab6174932a6dccfe933a9a6e20951c3
b7943c93f4ee204be69139d46e4d5c6b5193c5124c8576257592c301c03fe219cf6e3c5452d910f52ea03f70a287ff12380fc4e18223e4f2b74bd9d173a38a67d362
1955e686a7dff0f0384e65f4f038957250f3b1ac69981d72614738e3fae1119e775f129f1f38efa3034a11ebc19be70f11cd14f5ae55485201c1fc2e00055b6df766
2ca33e1dc06c3dcff7b919cd191657ea632f5001bd502939d335200009f68f7a4066aa5b377c5f1452f661884ff9e3e6ae70b39b4066469676f616c8860041311020
020050251a02038021b03060b090807030204150208030416020301021e01021780000a0910da320b23634f912fa9a9009f7bfe17b9b75b9ab4d2b23b9bf4d1b7eea
bd84cad00a0ca28702cdcc29f78a6990a7513c7ec83445f99aa9d023d0451a02039100800f7f8001f1d9f6b58425a8ebb7702e20fb20fde5157e97111158bc0c3731
f5695b92981433640ee966e032b7d268cba930824722956b4fd57830510067c9f4b940e8aa3406c3a0a1595b12d528fa6f6fc8e4db4cdb896bea1fd21456531a4632
6b63591d0b57243c59b1d7b938b8553d18a16b7f1fd5ba46930612b7881c940f824652f9aa289beedc35f72658881f83c9681171a7f9ce232ffaea03cfcf60e44930
413584cd56d32a9032f3da0700590f7d4d6b045d1b247a13e4f454940efaeceb6bc2ed9b069b08a148cb7f07f8101dcf6b984b39464a8d7f260a52823877950241d5
a78c8f95e52a69aba1d085127d334cada2a9982432a2a0a4747b0050300030507fe33999fb7a2d6b64bbf444fd18fbf13444e933a4d98cb8ffa636f64dadffcf09dd
52bcfc4567630d9e107424df5ad4e8c90fca2daaabf132e8f24f1e73d11a83fbb99629bfeaf7a3691be7c0a59346b7a6224dce1af4557d8e97fe7d86727e93a3fdb9
8fa47214b61786cf1ffe5882fd8075838854749cff6e5d9a03668b6e3ea12c1f669ca08138a01e252c1bda8ee0edc2701995a8c73205d90fd5bfc73740951e5fadf1
8d54876fca5c0dd9239f49abe5e15338846d6e15cd89e2cce68af2b44deb0fd547087719d3953bc589e12a68fdaba46e967d554eecde598965d83ae6b3cd1484b5f4
e39c66519f1f969a451be4a36f5614a0f05ee807b5ab28c1ffd00015408d98f68e307b0383a6d9a68ec0a5925b26c896e990530a88d6605e04d82fb96cf42889eb73
88813957a2e13dd8849041811020009050251a02039021b0c000a0910da320b23634f912f1fd300a0a520a7851c3eb2863e169839b7b2078eeb2a36dd009f411e332
7bbc79bb241cda292656d81f66e34ec62

使用公钥加密字符串'i am digoal' :

digoal=# select pgp_pub_encrypt('i am digoal', '\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');

加密后的数据 :

\xc1c14e031b437bccd670d8451007fe2d921731879c4044946d8f5fc88fb40d4701895534d8d370882ac22b8ea899b014df1a835d3d5520a681c184816acef966e
9a57201810eee18136dd8a148d81811de3f39ebaa7ada4e022fa3ce0f5d62937cad62ef28dbef8864f78c48f56ae932e8b2361d74dd3792388689e1443a77a06b81a
a4a0bf0cb1d3158130c097d4f22483609e8c317914f3b99966d9274856884894917a1d0b1389ad62d303600edaed7edba52b9fd3890386fa9579089dbbe60124ba5d
d211a710fb352e7400e2b13c139b6b9a7fc03308852ac19447afd01e660be6a72b4a2c0985f8abc66fbb874455c6f83cec73b51269538be7cc43229c37ae5658102c
02c44e73cd60866550800dbbb466956161875455f5554db33b52b6897d78c8613a75d6627cd7cc5be2f5685bc67bcce04f2d9aef40404bd10ac1a5b3510c60c9b522
0f2e8c87564ca133529282c04766aa902dddd19b2da3ddd8b5d95991276c4bcff6c720fa32522898567bb93bacef655f35c6b92bf72d6f75442b37f3c5fa05b1c903
f25ff470e69340c946a2d985d2f384c7c1f99f7df8f0189366189af895d1615d6974adafeea2519e27b5b82a5d094a20fb8215bf7ed3f0f58c58b5fbe331da0bcfd4
9bf94426ba2e5db02b43a54ac9046fb11238e010b10cf4d9fec036ce1abb695b5462934f968682da6861583b58695b312a3d511b5e8091f6668ad116199567b453d7
f51dfd23c0142070d0559e7e63c8ca3ed9363937184b90e273948e3dc80f121074f0f0b01f980a2d534683fc4b45131380cd70a564f33b72e6c812d858695dbb4

使用私钥解密这串bytea.

digoal=# select pgp_pub_decrypt('\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','\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');
 pgp_pub_decrypt 
-----------------
 i am digoal
(1 row)

使用pgp_key_id可以在加密后的数据中取出这分数据是通过对称密钥还是公钥加密的.

pgp_key_id(bytea) returns text

例如 :

digoal=# select pgp_key_id('\xc30d0404030245811e051118cc136ed23f0198808f069b53264d4a08c2b5dcf3b1c39a34d091263f7f6b64a14808e6ffb32ccc09749105b9cc062d70c628357ab1e2474ff6d109dd083ce892cfa55706');
 pgp_key_id 
------------
 SYMKEY
(1 row)
digoal=# select pgp_key_id('\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');
    pgp_key_id    
------------------
 1B437BCCD670D845
(1 row)

bytea和ASCII-armor格式转换

使用以下函数可以将加密后的数据bytea, 转换成PGP ASCII-armor格式.
或者反向转换.

armor(data bytea) returns text
dearmor(data text) returns bytea

用于产生随机的加密数据bytea的函数

gen_random_bytes(count integer) returns bytea

小结

1. crypt+gen_salt 加密速度慢, 被破解的难度高. 密码字符串通常较短, 并且有非常高的安全要求, 所以比较适合用于对密码字段进行加密.
2. 对称加密则比较适合数据量较大, 并且有安全需求的加密. 通常为了使用方便加密的密钥可以存储在本地库中, 为了提高安全, 也可以把加密的密钥存储在客户端或者其他数据库中.
3. 公钥加密手段与对称加密类似, 只是需要生成钥匙对. 使用公钥加密后的数据解密需要用到对应的私钥. 如果私钥加了passphrase保护, 解密时还需要提供私钥的passphrase.

参考

1. http://www.postgresql.org/docs/9.3/static/pgcrypto.html
2. http://www.gnupg.org/gph/en/manual.html
3. http://blog.163.com/digoal@126/blog/static/163877040201342233131835/
4. http://blog.163.com/digoal@126/blog/static/163877040201342383123592/
5. http://blog.163.com/digoal@126/blog/static/163877040201342335842432/
6. http://blog.163.com/digoal@126/blog/static/1638770402013423384517/
7. http://blog.163.com/digoal@126/blog/static/163877040201342443944861/

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