Encrypt Data and Database Connections

This document describes how to encrypt data at rest in the database or in transit over the network, to protect from eavesdroppers or man-in-the-middle attacks.

• Connections between clients and the coordinator database can be encrypted with SSL. This is enabled with the ssl server configuration parameter, which is off by default. Setting the ssl parameter to on allows client communications with the coordinator to be encrypted. The coordinator database must be set up for SSL. See OpenSSL Configuration for more about encrypting client connections with SSL.
• Apache Cloudberry allows SSL encryption of data in transit between the Cloudberry parallel file distribution server, gpfdist, and segment hosts. See Encrypting gpfdist Connections for more information. 
• The pgcrypto module of encryption/decryption functions protects data at rest in the database. Encryption at the column level protects sensitive information, such as social security numbers or credit card numbers. See Encrypting Data at Rest with pgcrypto for more information.

Encrypt gpfdist connections

The gpfdists protocol is a secure version of the gpfdist protocol that securely identifies the file server and the Apache Cloudberry and encrypts the communications between them. Using gpfdists protects against eavesdropping and man-in-the-middle attacks.

The gpfdists protocol implements client/server SSL security with the following notable features:

• Client certificates are required.
• Multilingual certificates are not supported.
• A Certificate Revocation List (CRL) is not supported.
• A minimum TLS version of 1.2 is required.
• SSL renegotiation is supported.
• The SSL ignore host mismatch parameter is set to false.
• Private keys containing a passphrase are not supported for the gpfdist file server (server.key) or for the Apache Cloudberry (client.key).
• It is the user's responsibility to issue certificates that are appropriate for the operating system in use. Generally, converting certificates to the required format is supported, for example using the SSL Converter at https://www.sslshopper.com/ssl-converter.html.

A gpfdist server started with the --ssl option can only communicate with the gpfdists protocol. A gpfdist server started without the --ssl option can only communicate with the gpfdist protocol. For more detail about gpfdist, see gpfdist.

There are two ways to enable the gpfdists protocol:

• Run gpfdist with the --ssl option and then use the gpfdists protocol in the LOCATION clause of a CREATE EXTERNAL TABLE statement.
• Use a YAML control file with the SSL option set to true and run gpload. Running gpload starts the gpfdist server with the --ssl option and then uses the gpfdists protocol.

When using gpfdists, the following client certificates must be located in the $PGDATA/gpfdists directory on each segment:

• The client certificate file, client.crt
• The client private key file, client.key
• The trusted certificate authorities, root.crt

caution

Do not protect the private key with a passphrase. The server does not prompt for a passphrase for the private key, and loading data fails with an error if one is required.

When using gpload with SSL you specify the location of the server certificates in the YAML control file. When using gpfdist with SSL, you specify the location of the server certificates with the --ssl option.

The following example shows how to securely load data into an external table. The example creates a readable external table named ext_expenses from all files with the txt extension, using the gpfdists protocol. The files are formatted with a pipe (|) as the column delimiter and an empty space as null.

1. Run gpfdist with the --ssl option on the segment hosts.

2. Log into the database and run the following command:

   =# CREATE EXTERNAL TABLE ext_expenses 
      ( name text, date date, amount float4, category text, desc1 text )
   LOCATION ('gpfdists://etlhost-1:8081/*.txt', 'gpfdists://etlhost-2:8082/*.txt')
   FORMAT 'TEXT' ( DELIMITER '|' NULL ' ') ;

Encrypt data at rest with pgcrypto

The pgcrypto module for Apache Cloudberry provides functions for encrypting data at rest in the database. Administrators can encrypt columns with sensitive information, such as social security numbers or credit card numbers, to provide an extra layer of protection. Database data stored in encrypted form cannot be read by users who do not have the encryption key, and the data cannot be read directly from disk.

pgcrypto is installed by default when you install Apache Cloudberry. You must explicitly enable pgcrypto in each database in which you want to use the module.

pgcrypto allows PGP encryption using symmetric and asymmetric encryption. Symmetric encryption encrypts and decrypts data using the same key and is faster than asymmetric encryption. It is the preferred method in an environment where exchanging secret keys is not an issue. With asymmetric encryption, a public key is used to encrypt data and a private key is used to decrypt data. This is slower then symmetric encryption and it requires a stronger key.

Using pgcrypto always comes at the cost of performance and maintainability. It is important to use encryption only with the data that requires it. Also, keep in mind that you cannot search encrypted data by indexing the data.

Before you implement in-database encryption, consider the following PGP limitations.

• No support for signing. That also means that it is not checked whether the encryption sub-key belongs to the coordinator key.
• No support for encryption key as coordinator key. This practice is generally discouraged, so this limitation should not be a problem.
• No support for several subkeys. This may seem like a problem, as this is common practice. On the other hand, you should not use your regular GPG/PGP keys with pgcrypto, but create new ones, as the usage scenario is rather different.

Apache Cloudberry is compiled with zlib by default; this allows PGP encryption functions to compress data before encrypting. When compiled with OpenSSL, more algorithms will be available.

Because pgcrypto functions run inside the database server, the data and passwords move between pgcrypto and the client application in clear-text. For optimal security, you should connect locally or use SSL connections and you should trust both the system and database administrators.

pgcrypto configures itself according to the findings of the main PostgreSQL configure script.

When compiled with zlib, pgcrypto encryption functions are able to compress data before encrypting.

Pgcrypto has various levels of encryption ranging from basic to advanced built-in functions. The following table shows the supported encryption algorithms.

Value functionality	Built-in	With OpenSSL
MD5	yes	yes
SHA1	yes	yes
SHA224/256/384/512	yes	yes
Other digest algorithms	no	yes
Blowfish	yes	yes
AES	yes	yes
DES/3DES/CAST5	no	yes
Raw Encryption	yes	yes
PGP Symmetric-Key	yes	yes
PGP Public Key	yes	yes

Create PGP keys

To use PGP asymmetric encryption in Apache Cloudberry, you must first create public and private keys and install them.

This section assumes you are installing Apache Cloudberry on a Linux machine with the Gnu Privacy Guard (gpg) command line tool. Use the latest version of GPG to create keys. Download and install Gnu Privacy Guard (GPG) for your operating system from https://www.gnupg.org/download/. On the GnuPG website you will find installers for popular Linux distributions and links for Windows and Mac OS X installers.

1. As root, run the following command and choose option 1 from the menu:

   # gpg --gen-key 
   gpg (GnuPG) 2.0.14; Copyright (C) 2009 Free Software Foundation, Inc.
   This is free software: you are free to change and redistribute it.
   There is NO WARRANTY, to the extent permitted by law.
    
   gpg: directory '/root/.gnupg' created
   gpg: new configuration file '/root/.gnupg/gpg.conf' created
   gpg: WARNING: options in '/root/.gnupg/gpg.conf' are not yet active during this run
   gpg: keyring '/root/.gnupg/secring.gpg' created
   gpg: keyring '/root/.gnupg/pubring.gpg' created
   Please select what kind of key you want:
    (1) RSA and RSA (default)
    (2) DSA and Elgamal
    (3) DSA (sign only)
    (4) RSA (sign only)
   Your selection? **1**

2. Respond to the prompts and follow the instructions, as shown in this example:

   RSA keys may be between 1024 and 4096 bits long.
   What keysize do you want? (2048) Press enter to accept default key size
   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) **365**
   Key expires at Wed 13 Jan 2016 10:35:39 AM PST
   Is this correct? (y/N) **y**
   
   GnuPG needs to construct a user ID to identify your key.
   
   Real name: **John Doe**
   Email address: **jdoe@email.com**
   Comment: 
   You selected this USER-ID:
    "John Doe <jdoe@email.com>"
   
   Change (N)ame, (C)omment, (E)mail or (O)kay/(Q)uit? **O**
   You need a Passphrase to protect your secret key.
   *(For this demo the passphrase is blank.)*
   can't connect to '/root/.gnupg/S.gpg-agent': No such file or directory
   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".
   
   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: /root/.gnupg/trustdb.gpg: trustdb created
   gpg: key 2027CC30 marked as ultimately trusted
   public and secret key created and signed.
   
   gpg:  checking the trustdbgpg: 
         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
   gpg:  next trustdb check due at 2016-01-13
   pub   2048R/2027CC30 2015-01-13 [expires: 2016-01-13]
         Key fingerprint = 7EDA 6AD0 F5E0 400F 4D45   3259 077D 725E 2027 CC30
   uid                  John Doe <jdoe@email.com>
   sub   2048R/4FD2EFBB 2015-01-13 [expires: 2016-01-13]

3. List the PGP keys by entering the following command:

   gpg --list-secret-keys 
   /root/.gnupg/secring.gpg
   ------------------------
   sec   2048R/2027CC30 2015-01-13 [expires: 2016-01-13]
   uid                  John Doe <jdoe@email.com>
   ssb   2048R/4FD2EFBB 2015-01-13

   2027CC30 is the public key and will be used to encrypt data in the database. 4FD2EFBB is the private (secret) key and will be used to decrypt data.

4. Export the keys using the following commands:

   # gpg -a --export 4FD2EFBB > public.key
   # gpg -a --export-secret-keys 2027CC30 > secret.key

See the pgcrypto documentation for more information about PGP encryption functions.

Encrypt data in tables using PGP

This section shows how to encrypt data inserted into a column using the PGP keys you generated.

1. Dump the contents of the public.key file and then copy it to the clipboard:

   # cat public.key
   -----BEGIN PGP PUBLIC KEY BLOCK-----
   Version: GnuPG v2.0.14 (GNU/Linux)
               
   mQENBFS1Zf0BCADNw8Qvk1V1C36Kfcwd3Kpm/dijPfRyyEwB6PqKyA05jtWiXZTh
   2His1ojSP6LI0cSkIqMU9LAlncecZhRIhBhuVgKlGSgd9texg2nnSL9Admqik/yX
   R5syVKG+qcdWuvyZg9oOOmeyjhc3n+kkbRTEMuM3flbMs8shOwzMvstCUVmuHU/V
   vG5rJAe8PuYDSJCJ74I6w7SOH3RiRIc7IfL6xYddV42l3ctd44bl8/i71hq2UyN2
   /Hbsjii2ymg7ttw3jsWAx2gP9nssDgoy8QDy/o9nNqC8EGlig96ZFnFnE6Pwbhn+
   ic8MD0lK5/GAlR6Hc0ZIHf8KEcavruQlikjnABEBAAG0HHRlc3Qga2V5IDx0ZXN0
   a2V5QGVtYWlsLmNvbT6JAT4EEwECACgFAlS1Zf0CGwMFCQHhM4AGCwkIBwMCBhUI
   AgkKCwQWAgMBAh4BAheAAAoJEAd9cl4gJ8wwbfwH/3VyVsPkQl1owRJNxvXGt1bY
   7BfrvU52yk+PPZYoes9UpdL3CMRk8gAM9bx5Sk08q2UXSZLC6fFOpEW4uWgmGYf8
   JRoC3ooezTkmCBW8I1bU0qGetzVxopdXLuPGCE7hVWQe9HcSntiTLxGov1mJAwO7
   TAoccXLbyuZh9Rf5vLoQdKzcCyOHh5IqXaQOT100TeFeEpb9TIiwcntg3WCSU5P0
   DGoUAOanjDZ3KE8Qp7V74fhG1EZVzHb8FajR62CXSHFKqpBgiNxnTOk45NbXADn4
   eTUXPSnwPi46qoAp9UQogsfGyB1XDOTB2UOqhutAMECaM7VtpePv79i0Z/NfnBe5
   AQ0EVLVl/QEIANabFdQ+8QMCADOipM1bF/JrQt3zUoc4BTqICaxdyzAfz0tUSf/7
   Zro2us99GlARqLWd8EqJcl/xmfcJiZyUam6ZAzzFXCgnH5Y1sdtMTJZdLp5WeOjw
   gCWG/ZLu4wzxOFFzDkiPv9RDw6e5MNLtJrSp4hS5o2apKdbO4Ex83O4mJYnav/rE
   iDDCWU4T0lhv3hSKCpke6LcwsX+7liozp+aNmP0Ypwfi4hR3UUMP70+V1beFqW2J
   bVLz3lLLouHRgpCzla+PzzbEKs16jq77vG9kqZTCIzXoWaLljuitRlfJkO3vQ9hO
   v/8yAnkcAmowZrIBlyFg2KBzhunYmN2YvkUAEQEAAYkBJQQYAQIADwUCVLVl/QIb
   DAUJAeEzgAAKCRAHfXJeICfMMOHYCACFhInZA9uAM3TC44l+MrgMUJ3rW9izrO48
   WrdTsxR8WkSNbIxJoWnYxYuLyPb/shc9k65huw2SSDkj//0fRrI61FPHQNPSvz62
   WH+N2lasoUaoJjb2kQGhLOnFbJuevkyBylRz+hI/+8rJKcZOjQkmmK8Hkk8qb5x/
   HMUc55H0g2qQAY0BpnJHgOOQ45Q6pk3G2/7Dbek5WJ6K1wUrFy51sNlGWE8pvgEx
   /UUZB+dYqCwtvX0nnBu1KNCmk2AkEcFK3YoliCxomdOxhFOv9AKjjojDyC65KJci
   Pv2MikPS2fKOAg1R3LpMa8zDEtl4w3vckPQNrQNnYuUtfj6ZoCxv
   =XZ8J
   -----END PGP PUBLIC KEY BLOCK-----

2. Create a table called userssn and insert some sensitive data, social security numbers for Bob and Alice, in this example. Paste the public.key contents after dearmor(.

   CREATE TABLE userssn( ssn_id SERIAL PRIMARY KEY, 
       username varchar(100), ssn bytea); 
   
   INSERT INTO userssn(username, ssn)
   SELECT robotccs.username, pgp_pub_encrypt(robotccs.ssn, keys.pubkey) AS ssn
   FROM ( 
           VALUES ('Alice', '123-45-6788'), ('Bob', '123-45-6799')) 
               AS robotccs(username, ssn)
   CROSS JOIN  (SELECT  dearmor('-----BEGIN PGP PUBLIC KEY BLOCK-----
   Version: GnuPG v2.0.14 (GNU/Linux)
               
   mQENBFS1Zf0BCADNw8Qvk1V1C36Kfcwd3Kpm/dijPfRyyEwB6PqKyA05jtWiXZTh
   2His1ojSP6LI0cSkIqMU9LAlncecZhRIhBhuVgKlGSgd9texg2nnSL9Admqik/yX
   R5syVKG+qcdWuvyZg9oOOmeyjhc3n+kkbRTEMuM3flbMs8shOwzMvstCUVmuHU/V
   vG5rJAe8PuYDSJCJ74I6w7SOH3RiRIc7IfL6xYddV42l3ctd44bl8/i71hq2UyN2
   /Hbsjii2ymg7ttw3jsWAx2gP9nssDgoy8QDy/o9nNqC8EGlig96ZFnFnE6Pwbhn+
   ic8MD0lK5/GAlR6Hc0ZIHf8KEcavruQlikjnABEBAAG0HHRlc3Qga2V5IDx0ZXN0
   a2V5QGVtYWlsLmNvbT6JAT4EEwECACgFAlS1Zf0CGwMFCQHhM4AGCwkIBwMCBhUI
   AgkKCwQWAgMBAh4BAheAAAoJEAd9cl4gJ8wwbfwH/3VyVsPkQl1owRJNxvXGt1bY
   7BfrvU52yk+PPZYoes9UpdL3CMRk8gAM9bx5Sk08q2UXSZLC6fFOpEW4uWgmGYf8
   JRoC3ooezTkmCBW8I1bU0qGetzVxopdXLuPGCE7hVWQe9HcSntiTLxGov1mJAwO7
   TAoccXLbyuZh9Rf5vLoQdKzcCyOHh5IqXaQOT100TeFeEpb9TIiwcntg3WCSU5P0
   DGoUAOanjDZ3KE8Qp7V74fhG1EZVzHb8FajR62CXSHFKqpBgiNxnTOk45NbXADn4
   eTUXPSnwPi46qoAp9UQogsfGyB1XDOTB2UOqhutAMECaM7VtpePv79i0Z/NfnBe5
   AQ0EVLVl/QEIANabFdQ+8QMCADOipM1bF/JrQt3zUoc4BTqICaxdyzAfz0tUSf/7
   Zro2us99GlARqLWd8EqJcl/xmfcJiZyUam6ZAzzFXCgnH5Y1sdtMTJZdLp5WeOjw
   gCWG/ZLu4wzxOFFzDkiPv9RDw6e5MNLtJrSp4hS5o2apKdbO4Ex83O4mJYnav/rE
   iDDCWU4T0lhv3hSKCpke6LcwsX+7liozp+aNmP0Ypwfi4hR3UUMP70+V1beFqW2J
   bVLz3lLLouHRgpCzla+PzzbEKs16jq77vG9kqZTCIzXoWaLljuitRlfJkO3vQ9hO
   v/8yAnkcAmowZrIBlyFg2KBzhunYmN2YvkUAEQEAAYkBJQQYAQIADwUCVLVl/QIb
   DAUJAeEzgAAKCRAHfXJeICfMMOHYCACFhInZA9uAM3TC44l+MrgMUJ3rW9izrO48
   WrdTsxR8WkSNbIxJoWnYxYuLyPb/shc9k65huw2SSDkj//0fRrI61FPHQNPSvz62
   WH+N2lasoUaoJjb2kQGhLOnFbJuevkyBylRz+hI/+8rJKcZOjQkmmK8Hkk8qb5x/
   HMUc55H0g2qQAY0BpnJHgOOQ45Q6pk3G2/7Dbek5WJ6K1wUrFy51sNlGWE8pvgEx
   /UUZB+dYqCwtvX0nnBu1KNCmk2AkEcFK3YoliCxomdOxhFOv9AKjjojDyC65KJci
   Pv2MikPS2fKOAg1R3LpMa8zDEtl4w3vckPQNrQNnYuUtfj6ZoCxv
   =XZ8J
   -----END PGP PUBLIC KEY BLOCK-----' AS pubkey) AS keys;

3. Verify that the ssn column is encrypted.

   test_db=# select * from userssn;
   ssn_id   | 1
   username | Alice
   ssn      | \301\300L\003\235M%_O\322\357\273\001\010\000\272\227\010\341\216\360\217C\020\261)_\367
   [\227\034\313:C\354d<\337\006Q\351('\2330\031lX\263Qf\341\262\200\3015\235\036AK\242fL+\315g\322
   7u\270*\304\361\355\220\021\330"\200%\264\274}R\213\377\363\235\366\030\023)\364!\331\303\237t\277=
   f \015\004\242\231\263\225%\032\271a\001\035\277\021\375X\232\304\305/\340\334\0131\325\344[~\362\0
   37-\251\336\303\340\377_\011\275\301/MY\334\343\245\244\372y\257S\374\230\346\277\373W\346\230\276\
   017fi\226Q\307\012\326\3646\000\326\005:E\364W\252=zz\010(:\343Y\237\257iqU\0326\350=v0\362\327\350\
   315G^\027:K_9\254\362\354\215<\001\304\357\331\355\323,\302\213Fe\265\315\232\367\254\245%(\\\373
   4\254\230\331\356\006B\257\333\326H\022\013\353\216F?\023\220\370\035vH5/\227\344b\322\227\026\362=\
   42\033\322<\001}\243\224;)\030zqX\214\340\221\035\275U\345\327\214\032\351\223c\2442\345\304K\016\
   011\214\307\227\237\270\026'R\205\205a~1\263\236[\037C\260\031\205\374\245\317\033k|\366\253\037
   ---------+--------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------------------------------
   ------------------------------------------------------------------------------
   ssn_id   | 2
   username | Bob
   ssn      | \301\300L\003\235M%_O\322\357\273\001\007\377t>\345\343,\200\256\272\300\012\033M4\265\032L
   L[v\262k\244\2435\264\232B\357\370d9\375\011\002\327\235<\246\210b\030\012\337@\226Z\361\246\032\00
   7'\012c\353]\355d7\360T\335\314\367\370;X\371\350*\231\212\260B\010#RQ0\223\253c7\0132b\355\242\233\34
   1\000\370\370\366\013\022\357\005i\202~\005\\z\301o\012\230Z\014\362\244\324&\243g\351\362\325\375
   \213\032\226$\2751\256XR\346k\266\030\234\267\201vUh\004\250\337A\231\223u\247\366/i\022\275\276\350\2
   20\316\306|\203+\010\261;\232\254tp\255\243\261\373Rq;\316w\357\006\207\374U\333\365\365\245hg\031\005
   \322\347ea\220\015l\212g\337\264\336b\263\004\311\210.4\340G+\221\274D\035\375\2216\241'\346a0\273wE\2
   12\342y^\202\262|A7\202t\240\333p\345G\373\253\243oCO\011\360\247\211\014\024{\272\271\322<\001\267
   \347\240\005\213\0078\036\210\307$\317\322\311\222\035\354\006<\266\264\004\376\251q\256\220(+\030\
   3270\013c\327\272\212%\363\033\252\322\337\354\276\225\232\201\212^\304\210\2269@\3230\370{

4. Extract the public.key ID from the database:

   SELECT pgp_key_id(dearmor('-----BEGIN PGP PUBLIC KEY BLOCK-----
   Version: GnuPG v2.0.14 (GNU/Linux)
   
   mQENBFS1Zf0BCADNw8Qvk1V1C36Kfcwd3Kpm/dijPfRyyEwB6PqKyA05jtWiXZTh
   2His1ojSP6LI0cSkIqMU9LAlncecZhRIhBhuVgKlGSgd9texg2nnSL9Admqik/yX
   R5syVKG+qcdWuvyZg9oOOmeyjhc3n+kkbRTEMuM3flbMs8shOwzMvstCUVmuHU/V
   vG5rJAe8PuYDSJCJ74I6w7SOH3RiRIc7IfL6xYddV42l3ctd44bl8/i71hq2UyN2
   /Hbsjii2ymg7ttw3jsWAx2gP9nssDgoy8QDy/o9nNqC8EGlig96ZFnFnE6Pwbhn+
   ic8MD0lK5/GAlR6Hc0ZIHf8KEcavruQlikjnABEBAAG0HHRlc3Qga2V5IDx0ZXN0
   a2V5QGVtYWlsLmNvbT6JAT4EEwECACgFAlS1Zf0CGwMFCQHhM4AGCwkIBwMCBhUI
   AgkKCwQWAgMBAh4BAheAAAoJEAd9cl4gJ8wwbfwH/3VyVsPkQl1owRJNxvXGt1bY
   7BfrvU52yk+PPZYoes9UpdL3CMRk8gAM9bx5Sk08q2UXSZLC6fFOpEW4uWgmGYf8
   JRoC3ooezTkmCBW8I1bU0qGetzVxopdXLuPGCE7hVWQe9HcSntiTLxGov1mJAwO7
   TAoccXLbyuZh9Rf5vLoQdKzcCyOHh5IqXaQOT100TeFeEpb9TIiwcntg3WCSU5P0
   DGoUAOanjDZ3KE8Qp7V74fhG1EZVzHb8FajR62CXSHFKqpBgiNxnTOk45NbXADn4
   eTUXPSnwPi46qoAp9UQogsfGyB1XDOTB2UOqhutAMECaM7VtpePv79i0Z/NfnBe5
   AQ0EVLVl/QEIANabFdQ+8QMCADOipM1bF/JrQt3zUoc4BTqICaxdyzAfz0tUSf/7
   Zro2us99GlARqLWd8EqJcl/xmfcJiZyUam6ZAzzFXCgnH5Y1sdtMTJZdLp5WeOjw
   gCWG/ZLu4wzxOFFzDkiPv9RDw6e5MNLtJrSp4hS5o2apKdbO4Ex83O4mJYnav/rE
   iDDCWU4T0lhv3hSKCpke6LcwsX+7liozp+aNmP0Ypwfi4hR3UUMP70+V1beFqW2J
   bVLz3lLLouHRgpCzla+PzzbEKs16jq77vG9kqZTCIzXoWaLljuitRlfJkO3vQ9hO
   v/8yAnkcAmowZrIBlyFg2KBzhunYmN2YvkUAEQEAAYkBJQQYAQIADwUCVLVl/QIb
   DAUJAeEzgAAKCRAHfXJeICfMMOHYCACFhInZA9uAM3TC44l+MrgMUJ3rW9izrO48
   WrdTsxR8WkSNbIxJoWnYxYuLyPb/shc9k65huw2SSDkj//0fRrI61FPHQNPSvz62
   WH+N2lasoUaoJjb2kQGhLOnFbJuevkyBylRz+hI/+8rJKcZOjQkmmK8Hkk8qb5x/
   HMUc55H0g2qQAY0BpnJHgOOQ45Q6pk3G2/7Dbek5WJ6K1wUrFy51sNlGWE8pvgEx
   /UUZB+dYqCwtvX0nnBu1KNCmk2AkEcFK3YoliCxomdOxhFOv9AKjjojDyC65KJci
   Pv2MikPS2fKOAg1R3LpMa8zDEtl4w3vckPQNrQNnYuUtfj6ZoCxv
   =XZ8J
   -----END PGP PUBLIC KEY BLOCK-----'));
   
   pgp_key_id | 9D4D255F4FD2EFBB

   This shows that the PGP key ID used to encrypt the ssn column is 9D4D255F4FD2EFBB. It is recommended to perform this step whenever a new key is created and then store the ID for tracking.

   You can use this key to see which key pair was used to encrypt the data:

   SELECT username, pgp_key_id(ssn) As key_used
   FROM userssn;
   username | Bob
   key_used | 9D4D255F4FD2EFBB
   ---------+-----------------
   username | Alice
   key_used | 9D4D255F4FD2EFBB
   

   note

   Different keys may have the same ID. This is rare, but is a normal event. The client application should try to decrypt with each one to see which fits — like handling ANYKEY. See pgp_key_id() in the pgcrypto documentation.

5. Decrypt the data using the private key.

   SELECT username, pgp_pub_decrypt(ssn, keys.privkey) 
                    AS decrypted_ssn FROM userssn
                    CROSS JOIN
                    (SELECT dearmor('-----BEGIN PGP PRIVATE KEY BLOCK-----
   Version: GnuPG v2.0.14 (GNU/Linux)
   
   lQOYBFS1Zf0BCADNw8Qvk1V1C36Kfcwd3Kpm/dijPfRyyEwB6PqKyA05jtWiXZTh
   2His1ojSP6LI0cSkIqMU9LAlncecZhRIhBhuVgKlGSgd9texg2nnSL9Admqik/yX
   R5syVKG+qcdWuvyZg9oOOmeyjhc3n+kkbRTEMuM3flbMs8shOwzMvstCUVmuHU/V
   vG5rJAe8PuYDSJCJ74I6w7SOH3RiRIc7IfL6xYddV42l3ctd44bl8/i71hq2UyN2
   /Hbsjii2ymg7ttw3jsWAx2gP9nssDgoy8QDy/o9nNqC8EGlig96ZFnFnE6Pwbhn+
   ic8MD0lK5/GAlR6Hc0ZIHf8KEcavruQlikjnABEBAAEAB/wNfjjvP1brRfjjIm/j
   XwUNm+sI4v2Ur7qZC94VTukPGf67lvqcYZJuqXxvZrZ8bl6mvl65xEUiZYy7BNA8
   fe0PaM4Wy+Xr94Cz2bPbWgawnRNN3GAQy4rlBTrvqQWy+kmpbd87iTjwZidZNNmx
   02iSzraq41Rt0Zx21Jh4rkpF67ftmzOH0vlrS0bWOvHUeMY7tCwmdPe9HbQeDlPr
   n9CllUqBn4/acTtCClWAjREZn0zXAsNixtTIPC1V+9nO9YmecMkVwNfIPkIhymAM
   OPFnuZ/Dz1rCRHjNHb5j6ZyUM5zDqUVnnezktxqrOENSxm0gfMGcpxHQogUMzb7c
   6UyBBADSCXHPfo/VPVtMm5p1yGrNOR2jR2rUj9+poZzD2gjkt5G/xIKRlkB4uoQl
   emu27wr9dVEX7ms0nvDq58iutbQ4d0JIDlcHMeSRQZluErblB75Vj3HtImblPjpn
   4Jx6SWRXPUJPGXGI87u0UoBH0Lwij7M2PW7l1ao+MLEA9jAjQwQA+sr9BKPL4Ya2
   r5nE72gsbCCLowkC0rdldf1RGtobwYDMpmYZhOaRKjkOTMG6rCXJxrf6LqiN8w/L
   /gNziTmch35MCq/MZzA/bN4VMPyeIlwzxVZkJLsQ7yyqX/A7ac7B7DH0KfXciEXW
   MSOAJhMmklW1Q1RRNw3cnYi8w3q7X40EAL/w54FVvvPqp3+sCd86SAAapM4UO2R3
   tIsuNVemMWdgNXwvK8AJsz7VreVU5yZ4B8hvCuQj1C7geaN/LXhiT8foRsJC5o71
   Bf+iHC/VNEv4k4uDb4lOgnHJYYyifB1wC+nn/EnXCZYQINMia1a4M6Vqc/RIfTH4
   nwkZt/89LsAiR/20HHRlc3Qga2V5IDx0ZXN0a2V5QGVtYWlsLmNvbT6JAT4EEwEC
   ACgFAlS1Zf0CGwMFCQHhM4AGCwkIBwMCBhUIAgkKCwQWAgMBAh4BAheAAAoJEAd9
   cl4gJ8wwbfwH/3VyVsPkQl1owRJNxvXGt1bY7BfrvU52yk+PPZYoes9UpdL3CMRk
   8gAM9bx5Sk08q2UXSZLC6fFOpEW4uWgmGYf8JRoC3ooezTkmCBW8I1bU0qGetzVx
   opdXLuPGCE7hVWQe9HcSntiTLxGov1mJAwO7TAoccXLbyuZh9Rf5vLoQdKzcCyOH
   h5IqXaQOT100TeFeEpb9TIiwcntg3WCSU5P0DGoUAOanjDZ3KE8Qp7V74fhG1EZV
   zHb8FajR62CXSHFKqpBgiNxnTOk45NbXADn4eTUXPSnwPi46qoAp9UQogsfGyB1X
   DOTB2UOqhutAMECaM7VtpePv79i0Z/NfnBedA5gEVLVl/QEIANabFdQ+8QMCADOi
   pM1bF/JrQt3zUoc4BTqICaxdyzAfz0tUSf/7Zro2us99GlARqLWd8EqJcl/xmfcJ
   iZyUam6ZAzzFXCgnH5Y1sdtMTJZdLp5WeOjwgCWG/ZLu4wzxOFFzDkiPv9RDw6e5
   MNLtJrSp4hS5o2apKdbO4Ex83O4mJYnav/rEiDDCWU4T0lhv3hSKCpke6LcwsX+7
   liozp+aNmP0Ypwfi4hR3UUMP70+V1beFqW2JbVLz3lLLouHRgpCzla+PzzbEKs16
   jq77vG9kqZTCIzXoWaLljuitRlfJkO3vQ9hOv/8yAnkcAmowZrIBlyFg2KBzhunY
   mN2YvkUAEQEAAQAH/A7r4hDrnmzX3QU6FAzePlRB7niJtE2IEN8AufF05Q2PzKU/
   c1S72WjtqMAIAgYasDkOhfhcxanTneGuFVYggKT3eSDm1RFKpRjX22m0zKdwy67B
   Mu95V2Oklul6OCm8dO6+2fmkGxGqc4ZsKy+jQxtxK3HG9YxMC0dvA2v2C5N4TWi3
   Utc7zh//k6IbmaLd7F1d7DXt7Hn2Qsmo8I1rtgPE8grDToomTnRUodToyejEqKyI
   ORwsp8n8g2CSFaXSrEyU6HbFYXSxZealhQJGYLFOZdR0MzVtZQCn/7n+IHjupndC
   Nd2a8DVx3yQS3dAmvLzhFacZdjXi31wvj0moFOkEAOCz1E63SKNNksniQ11lRMJp
   gaov6Ux/zGLMstwTzNouI+Kr8/db0GlSAy1Z3UoAB4tFQXEApoX9A4AJ2KqQjqOX
   cZVULenfDZaxrbb9Lid7ZnTDXKVyGTWDF7ZHavHJ4981mCW17lU11zHBB9xMlx6p
   dhFvb0gdy0jSLaFMFr/JBAD0fz3RrhP7e6Xll2zdBqGthjC5S/IoKwwBgw6ri2yx
   LoxqBr2pl9PotJJ/JUMPhD/LxuTcOZtYjy8PKgm5jhnBDq3Ss0kNKAY1f5EkZG9a
   6I4iAX/NekqSyF+OgBfC9aCgS5RG8hYoOCbp8na5R3bgiuS8IzmVmm5OhZ4MDEwg
   nQP7BzmR0p5BahpZ8r3Ada7FcK+0ZLLRdLmOYF/yUrZ53SoYCZRzU/GmtQ7LkXBh
   Gjqied9Bs1MHdNUolq7GaexcjZmOWHEf6w9+9M4+vxtQq1nkIWqtaphewEmd5/nf
   EP3sIY0EAE3mmiLmHLqBju+UJKMNwFNeyMTqgcg50ISH8J9FRIkBJQQYAQIADwUC
   VLVl/QIbDAUJAeEzgAAKCRAHfXJeICfMMOHYCACFhInZA9uAM3TC44l+MrgMUJ3r
   W9izrO48WrdTsxR8WkSNbIxJoWnYxYuLyPb/shc9k65huw2SSDkj//0fRrI61FPH
   QNPSvz62WH+N2lasoUaoJjb2kQGhLOnFbJuevkyBylRz+hI/+8rJKcZOjQkmmK8H
   kk8qb5x/HMUc55H0g2qQAY0BpnJHgOOQ45Q6pk3G2/7Dbek5WJ6K1wUrFy51sNlG
   WE8pvgEx/UUZB+dYqCwtvX0nnBu1KNCmk2AkEcFK3YoliCxomdOxhFOv9AKjjojD
   yC65KJciPv2MikPS2fKOAg1R3LpMa8zDEtl4w3vckPQNrQNnYuUtfj6ZoCxv
   =fa+6
   -----END PGP PRIVATE KEY BLOCK-----') AS privkey) AS keys;
   
   username | decrypted_ssn 
   ----------+---------------
    Alice    | 123-45-6788
    Bob      | 123-45-6799
   (2 rows)

   If you created a key with passphrase, you may have to enter it here. However for the purpose of this example, the passphrase is blank.

Key management

Whether you are using symmetric (single private key) or asymmetric (public and private key) cryptography, it is important to store the coordinator or private key securely. There are many options for storing encryption keys, for example, on a file system, key vault, encrypted USB, trusted platform module (TPM), or hardware security module (HSM).

Consider the following questions when planning for key management:

• Where will the keys be stored?
• When should keys expire?
• How are keys protected?
• How are keys accessed?
• How can keys be recovered and revoked?

The Open Web Application Security Project (OWASP) provides a very comprehensive guide to securing encryption keys.

Encrypt data using TDE

To meet the requirements for protecting user data security, Apache Cloudberry supports Transparent Data Encryption (TDE).

TDE is a technology used to encrypt database data files:

• "Data" refers to the data in the database.
• Files are stored in ciphertext on the hard drive disk and processed in plaintext in memory. TDE is used to protect static data, so it is also known as static data encryption.
• "Transparent" means users do not need to change their operational habits. TDE automatically manages the encryption/decryption process without user or application intervention.

For details, see Transparent Data Encryption.