List of cryptography functions

Encryption Quick Reference

Name	Value
Recommended public key algorithms	Curve25519, Ed25519, ECDSA, RSA
Recommended symmetric ciphers	Salsa20, ChaCha20, AES
Recommended minimum key size (symmetric)	128 bits
Preferred minimum key size (symmetric)	256 bits
Recommended minimum key size (RSA)	2048 bits
Preferred minimum key size (RSA)	4096 bits

Encryption Modes

Mode	AKA	Should use?	Authenticated?	Encryption parallelizable?	Decryption parallelizable?	Random read?	Notes
Electronic Code Book	ECB	No	No	Yes	Yes	Yes	Same plaintext yields same ciphertext.
Cipher Feedback	CFB	Yes	No	No	Yes	Yes
Output Feedback	OFB	Yes	No	No	No	No
Cipher Block Chaining	CBC	Yes	No	No	Yes	Yes
Counter	CTR	Yes	No	Yes	Yes	Yes
Galois Counter Mode	GCM	Recommended	Yes	Yes	Yes	No	Counter mode plus authentication, very efficient.

Symmetric Ciphers

Cipher	Block size (bits)	Key size (bits)	Stream?	Should use?	Estimated Time to Crack	Notes
AES	128	128,192,256		Yes
DES	64	56		No	In 2008 their COPACOBANA RIVYERA reduced the time to break DES to less than one day, using 128 Spartan-3 5000's.
3DES	64	168,112,56		No
Blowfish	64	32-448		Not ideal		This is the primary mode of encryption used in IRC encryption plugins.
ChaCha20		256	Yes	Yes
Salsa20		256	Yes	Yes
RC4		40-2048	Yes	No

Asymmetric Encryption

Cipher	ECC?	Signing	Encryption	DH Key exchange	Should use?	Minimum key size	Recommended key size	Notes
RSA	No	Yes	Yes	Yes	Yes	2048	4096
DSA	No	Yes	Yes	No	No	2048	4096
ElGamal	No	Yes	Yes	No	Yes	2048	4096
ECDSA	Yes	Yes	Yes	No	Yes	256	384
ECDH	Yes	No	No	Yes	Yes	256	384
Ed25519	Yes	Yes	Yes	No	Recommended	512	512
Curve25519	Yes	No	No	Yes	Recommended	256	256

Hash functions

Hash	Bits	Broken?	Should use?	Notes
MD5	128	Yes	No	Collisions can be generated at will with desktop computational power.
SHA-1	160	Yes	No	Collision are expensive to generate, but a sufficiently motivated adversary can do it.
SHA-2	224-512	No	Yes	Pseudo-collisions generated with partial SHA-256, no full attacks.
SHA-3 (Keccak)	224-512	No	Yes	Not widely implemented yet.

Key Derivation Functions (KDF)

Algorithm	Password?	Requires uniform random input?	Slow?	Notes
Bcrypt	Yes	No	Yes
Scrypt	Yes	No	Yes
PBKDF2	Yes	No	Yes
HKDF	No	Yes	No

Message Authentication Codes (MAC)

Algorithm	Hash-based?	Block cipher based?	Notes
Poly1305	No	Yes
HMAC	Yes	No
CBC-MAC	No	Yes
PMAC	No	Yes
CMAC	No	Yes