Archives:

Postgresql cheatsheat No ratings yet.

Connecting to MySQL:  mysql -u user_name -p Connecting to PostgreSQL: sudo -u postgres psql Description MySQL command PostgreSQL equivalent Show databases SHOW DATABASES; \l[ist] Use/Connect to a database named ‘some_database’ USE some_database; \c some_database Show tables/relations within one database SHOW TABLES; \dt Show table details (columns, types) DESCRIBE some_table; \d+ some_table Show indices of some_table (in • Read More »


DTLS, DTLS-SRTP No ratings yet.

DTLS:  Basically DTLS is to construct TLS over datagram (UDP, DCCP, etc.) DTLS is similar to TLS intentionally except that DTLS has to solve two problems: packet lost and reordering. DTLS-SRTP DTLS-SRTP can be viewed in two equivalent ways: as a new key management method for SRTP, and a new RTP-specific data format for DTLS. • Read More »


OpenPGP vs S/MIME No ratings yet.

S/MIME and OpenPGP similarity: both depends on public/private keys to encrypt/authenticate msg ( emails), difference:  how to distribute the public keys. S/MIME is similar to TLS, need to depends on X.509 certificate OpenPGP depends on web of trust to distribute the public key.   references: http://security.stackexchange.com/questions/7874/how-does-pgp-differ-from-s-mime Please rate this rating


What is the difference between srtp and zrtp No ratings yet.

SRTP sdp msg: v=0 o=jdoe 2890844526 2890842807 IN IP4 10.47.16.5 s=SDP Seminar i=A Seminar on the session description protocol u=http://www.example.com/seminars/sdp.pdf e=j.doe@example.com (Jane Doe) c=IN IP4 161.44.17.12/127 t=2873397496 2873404696 m=video 51372 RTP/SAVP 31 a=crypto:1 AES_CM_128_HMAC_SHA1_80 inline:d0RmdmcmVCspeEc3QGZiNWpVLFJhQX1cfHAwJSoj|2^20 m=audio 49170 RTP/SAVP 0 a=crypto:1 AES_CM_128_HMAC_SHA1_32 inline:NzB4d1BINUAvLEw6UzF3WSJ+PSdFcGdUJShpX1Zj|2^20 m=application 32416 udp wb a=orient:portrait The crypto line includes the master key and • Read More »


systemctl cheatsheat No ratings yet.

  Systemd template and instance (@) from: https://wiki.archlinux.org/index.php/systemd Note: Some unit names contain an @ sign (e.g. name@string.service): this means that they are instances of a template unit, whose actual file name does not contain the string part (e.g. name@.service). string is called the instance identifier, and is similar to an argument that is passed • Read More »


SSH protocol No ratings yet.

How SSH2 works: (1) When a TCP connection is made by a client, the server responds with the protocol versions it supports. If the client can match one of the acceptable protocol versions, the connection continues. The server also provides its public host key, which the client can use to check whether this was the • Read More »