scrypt - ActiveState ActiveGo 1.8
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Package scrypt

import "golang.org/x/crypto/scrypt"
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Package scrypt implements the scrypt key derivation function as defined in Colin Percival's paper "Stronger Key Derivation via Sequential Memory-Hard Functions" (http://www.tarsnap.com/scrypt/scrypt.pdf).

func Key 

func Key(password, salt []byte, N, r, p, keyLen int) ([]byte, error)

Key derives a key from the password, salt, and cost parameters, returning a byte slice of length keyLen that can be used as cryptographic key.

N is a CPU/memory cost parameter, which must be a power of two greater than 1. r and p must satisfy r * p < 2³⁰. If the parameters do not satisfy the limits, the function returns a nil byte slice and an error.

For example, you can get a derived key for e.g. AES-256 (which needs a 32-byte key) by doing: 

dk, err := scrypt.Key([]byte("some password"), salt, 16384, 8, 1, 32)

The recommended parameters for interactive logins as of 2009 are N=16384, r=8, p=1. They should be increased as memory latency and CPU parallelism increases. Remember to get a good random salt.