The US bureau of standards (NIST) has drafted some official recommendations for cryptographic key sizes, in bits. These are security guidelines. Here they are, along with the years of validity.

Algorithm	Now-2015	2016-2035	2036-Forever	Paranoid	Paranoid
Cipher	Skipjack	TDES	AES-128	AES-192	AES-256
Hash	SHA-1		SHA-256	SHA-384	SHA-512
Cipher key	80	112	128	192	256
EC order	160	224	256	384	512
DSA order	160	224	256	384	512
DSA modulus	1024	2048	3072	7680	15360
RSA modulus	1024	2048	3072	7680	15360