Hashes

Question 1

MD5 (Message Digest 5)

Answer 1

128-bit output

Deprecated - only used to verify integrity of files.

Question 2

SHA (Secure Hash Algorithm)

Answer 2

SHA-1: 160-bit output
SHA-2: -256, -512, -224, -384)
SHA-3 (Keccak): 224, 256, 382, 512

Question 3

HMAC (Hash-based Message Authentication)

Answer 3

Different versions using MD5 and SHA1 hashes.
Uses shared secret key to randomize; provides integrity (MD5/SHA1) and authenticity (shared key).
Helps protect against hacked hashes.
Often used by IPsec and TLS.

Question 4

RIPEMD (RACE Integrity Primitives Evaluation Message Digest)

Answer 4

Different version for 160, 128, 256 and 320 bits

Question 5

bcrypt

Answer 5

60 character string
Key stretching technique; common on Linux/Unix to protect passwords in shadow password file.
Salts password then encrypts with Blowfish block cipher. Can do multiple times to make more secure.

Question 6

PBKDF2 (Password-based Key Derivation Function 2)

Answer 6

128, 256 and 512 are common but depends on how implemented.
Key stretching technique which uses salts of at least 64 bits and a pseudo-random function like HMAC.
Used by WPA2, Apple iOS mobile and Cisco OS.
Some applications use the process up to 1M times.