pgcrypto 0.4 - cryptographic functions for PostgreSQL. ====================================================== by Marko Kreen INSTALLATION ============ Edit makefile, if you want to use any external library. NB! Default randomness source is libc random() function. This is so only to get pgcrypto build everywhere. Randomness is needed for gen_salt() and pgp_encrypt() functions. So if you plan using those, you should definitely change that by editing Makefile. You can should use urandom device if your OS supports it, otherwise link pgcrypto against OpenSSL library and use its PRNG. After editing Makefile: make make install To run regression tests, install both PostgreSQL and pgcrypto and then run make installcheck SQL FUNCTIONS ============= If any of arguments are NULL they return NULL. digest(data::bytea, type::text)::bytea Type is here the algorithm to use. E.g. 'md5', 'sha1', ... Returns binary hash. digest_exists(type::text)::bool Returns BOOL whether given hash exists. hmac(data::bytea, key::bytea, type::text)::bytea Calculates Hashed MAC over data. type is the same as in digest(). Returns binary hash. Similar to digest() but noone can alter data and re-calculate hash without knowing key. If the key is larger than hash blocksize it will first hashed and the hash will be used as key. [ HMAC is described in RFC2104. ] hmac_exists(type::text)::bool Returns BOOL. It is separate function because all hashes cannot be used in HMAC. crypt(password::text, salt::text)::text Calculates UN*X crypt(3) style hash. Useful for storing passwords. For generating salt you should use the gen_salt() function. Usage: New password: UPDATE .. SET pswhash = crypt(new_psw, gen_salt('md5')); Authentication: SELECT pswhash = crypt(given_psw, pswhash) WHERE .. ; returns BOOL whether the given_psw is correct. DES crypt has max key of 8 bytes, MD5 has max key at least 2^32-1 bytes but may be larger on some platforms... Builtin crypt() supports DES, Extended DES, MD5 and Blowfish (variant 2a) algorithms. gen_salt(type::text)::text Generates a new random salt for usage in crypt(). Type 'des' - Old UNIX, not recommended 'md5' - md5-based crypt() 'xdes' - 'Extended DES' 'bf' - Blowfish-based, variant 2a When you use --enable-system-crypt then note that system libcrypt may not support them all. gen_salt(type::text, rounds::int4)::text same as above, but lets user specify iteration count for algorithm. Number is algorithm specific: type default min max --------------------------------- xdes 725 1 16777215 bf 6 4 31 In case of xdes there is a additional limitation that the count must be a odd number. The higher the count, the more time it takes to calculate crypt and therefore the more time to break it. But beware! With too high count it takes a _very_long_ time to calculate it. For maximum security, you should choose the 'bf' crypt and use maximum number of rounds you can still tolerate. armor(bytea)::text dearmor(text)::bytea Those wrap/unwrap data into PGP Ascii Armor which is basically Base64 with CRC and additional formatting. pgp_sym_encrypt(data::text, key::text)::bytea pgp_sym_encrypt(data::text, key::text, arg::text)::bytea pgp_sym_encrypt_bytea(data::bytea, key::text)::bytea pgp_sym_encrypt_bytea(data::bytea, key::text, arg::text)::bytea pgp_sym_decrypt(data::bytea, key::text)::text pgp_sym_decrypt(data::bytea, key::text, arg::text)::text pgp_sym_decrypt_bytea(data::text, key::text)::bytea pgp_sym_decrypt_bytea(data::text, key::text, arg::text)::bytea Encrypt data into OpenPGP Symmetrically Encrypted Data message. And decrypt it from it. Note that the pgp_sym_encrypt_bytea functions tag the data as binary, as the pgp_sym_encrypt will tag the data as text. You can not decrypt the binary data as text. But you can decrypt text data as binary. This rule avoids having broken textual data in PostgreSQL. Both encrypt and decrypt accept also third argument, which is parameters to the function in following format: parm=val[,parm=val]... Example: select pgp_sym_encrypt('data', 'psw', 'compress-algo=2, unicode-mode=1'); Accepted parameters are: cipher-algo: bf, aes, aes128, aes192, aes256 Cipher algorithm to use. OpenSSL gives additional algorithms: 3des, cast5 Default: aes128 compress-algo: 0, 1, 2 Which compression algorithm to use. 0 - no compression 1 - ZIP compression 2 - ZLIB compression [=ZIP plus meta-data and block-CRC's] Default: 0 compress-level: 0, 1-9 How much to compress. Bigger level compresses smaller but also slower. 0 disables compression. Default: 6 convert-crlf: 0, 1 Whether to convert \n into \r\n when encrypting and \r\n to \n when decrypting. RFC2440 specifies that text packets should use "\r\n" line-feeds. Use this to get fully RFC-compliant behaviour. Default: 0 disable-mdc: 0, 1 Do not protect data with SHA-1. Note that SHA-1 protected packet is from upcoming update to RFC2440. (Currently at version RFC2440bis-13.) You need to disable it if you need compatibility with ancient PGP products. Recent gnupg.org and pgp.com software supports it fine. Default: 0 enable-session-key: 0, 1 Use separate session key. Default: 0 s2k-mode: 0, 1, 3 Which S2K algorithm to use. 0 is dangerous - without salt. Default: 3 s2k-digest-algo: md5, sha1 Which digest algorithm to use in S2K calculation. Default: SHA-1 s2k-cipher-algo: bf, aes, aes128, aes192, aes256 Which cipher to use for encrypting separate session key. Default: same as cipher-algo. unicode-mode: 0, 1 Whether to convert textual data from database internal encoding to UTF-8 and back. Default: 0 Only 'convert-crlf' applies to both encrypt and decrypt, all others apply only to encrypt - decrypt gets the settings from PGP data. pgp_pub_encrypt(data::text, key::bytea)::bytea pgp_pub_encrypt(data::text, key::bytea, arg::text)::bytea pgp_pub_encrypt_bytea(data::bytea, bytea::text)::bytea pgp_pub_encrypt_bytea(data::bytea, bytea::text, arg::text)::bytea pgp_pub_decrypt(data::bytea, key::bytea)::text pgp_pub_decrypt(data::bytea, key::bytea, psw::text)::text pgp_pub_decrypt(data::bytea, key::bytea, psw::text, arg::text)::text pgp_pub_decrypt_bytea(data::text, key::bytea)::bytea pgp_pub_decrypt_bytea(data::text, key::bytea, psw::text)::bytea pgp_pub_decrypt_bytea(data::text, key::bytea, psw::text, arg::bytea)::bytea Encrypt data into OpenPGP Public-Key Encrypted Data message. And decrypt it from it. The arg parameter is described in pgp_sym_* section. The key must be a public-key packet for pgp_pub_encrypt functions and a secret key packet for pgp_pub_decrypt functions. Trying to encrypt with secret key gives a error. While being technically possible, it is probably a sign of user error and leaking secret keys. Here is a example how to generate them: Generate a new key: gpg --gen-key You need to pick "DSA and Elgamal" key type, others are sign-only. List keys: gpg --list-secret-keys Export ascii-armored public key: gpg -a --export KEYID > public.key Export ascii-armored secret key: gpg -a --export-secret-keys KEYID > secret.key You need to use dearmor() on them before giving giving them to pgp_pub_* functions. Ofcourse, if you can handle binary data, you can drop "-a" from gpg. pgp_key_id(key / data) It shows you either key ID if given PGP public or secret key. Or it gives the key ID what was used for encrypting the data, if given encrypted data. It can return 2 special key ID's: SYMKEY - it got symmetrically encrypted data. ANYKEY - the data packet key ID is clear. That means you should try all you secret keys on it. encrypt(data::bytea, key::bytea, type::text)::bytea decrypt(data::bytea, key::bytea, type::text)::bytea encrypt_iv(data::bytea, key::bytea, iv::bytea, type::text)::bytea decrypt_iv(data::bytea, key::bytea, iv::bytea, type::text)::bytea Encrypt/decrypt data with cipher, padding data if needed. Pseudo-noteup: algo ['-' mode] ['/pad:' padding] Supported algorithms: bf - Blowfish aes, rijndael - Rijndael-128 Others depend on library and are not tested enough, so play on your own risk. Modes: 'cbc' (default), 'ecb'. Again, library may support more. Padding is 'pkcs' (default), 'none'. 'none' is mostly for testing ciphers, you should not need it. So, example: encrypt(data, 'fooz', 'bf') is equal to encrypt(data, 'fooz', 'bf-cbc/pad:pkcs') IV is initial value for mode, defaults to all zeroes. It is ignored for ECB. It is clipped or padded with zeroes if not exactly block size. ALGORITHMS ========== The standard functionality at the moment consists of Hashes: md5, sha1 Ciphers: bf, aes Modes: cbc, ecb TODO: write standard names for optional ciphers too. LIBRARIES ========= * crypt() internal: des, xdes, md5, bf -lcrypt: ??? (whatever you have) * other: [ This only lists stuff that the libraries claim to support. So pgcrypto may work with all of them. But ATM tested are only the standard ciphers. On others pgcrypto and library may mess something up. You have been warned. ] internal (default): Hashes: MD5, SHA1 Ciphers: Blowfish, Rijndael-128 OpenSSL (0.9.7): Hashes: MD5, SHA1, RIPEMD160, MD2 Ciphers: Blowfish, AES, CAST5, DES, 3DES License: BSD-like with strong advertisement Url: http://www.openssl.org/ CREDITS ======= I have used code from following sources: DES crypt() by David Burren and others FreeBSD libcrypt MD5 crypt() by Poul-Henning Kamp FreeBSD libcrypt Blowfish crypt() by Solar Designer www.openwall.com Blowfish cipher by Niels Provos OpenBSD sys/crypto Rijndael cipher by Brian Gladman OpenBSD sys/crypto MD5 and SHA1 by WIDE Project KAME kame/sys/crypto LEGALESE ======== * I owe a beer to Poul-Henning. * This product includes software developed by Niels Provos.