go-crypt/crypt/kdf.go
Claude 7407b89b8d
refactor(ax): AX RFC-025 compliance sweep pass 1
Remove banned imports (fmt, strings, os, errors, path/filepath) across all
production and test files, replace with core.* primitives, coreio.ReadStream,
and coreerr.E. Upgrade dappco.re/go/core v0.5.0 → v0.7.0 for core.PathBase
and core.Is. Fix isRepoScoped to exclude pr.* capabilities (enforcement is at
the forge layer, not the policy engine). Add Good/Bad/Ugly test coverage to
all packages missing the mandatory three-category naming convention.

Co-Authored-By: Virgil <virgil@lethean.io>
2026-03-31 08:48:56 +01:00

63 lines
1.9 KiB
Go

// Package crypt provides cryptographic utilities including encryption,
// hashing, key derivation, HMAC, and checksum functions.
package crypt
import (
"crypto/rand"
"crypto/sha256"
"io"
coreerr "dappco.re/go/core/log"
"golang.org/x/crypto/argon2"
"golang.org/x/crypto/hkdf"
"golang.org/x/crypto/scrypt"
)
// Argon2id default parameters.
const (
argon2Memory = 64 * 1024 // 64 MB
argon2Time = 3
argon2Parallelism = 4
argon2KeyLen = 32
argon2SaltLen = 16
)
// DeriveKey derives a key from a passphrase using Argon2id with default parameters.
//
// key := crypt.DeriveKey([]byte("passphrase"), salt16, 32)
func DeriveKey(passphrase, salt []byte, keyLen uint32) []byte {
return argon2.IDKey(passphrase, salt, argon2Time, argon2Memory, argon2Parallelism, keyLen)
}
// DeriveKeyScrypt derives a key from a passphrase using scrypt.
//
// key, err := crypt.DeriveKeyScrypt([]byte("passphrase"), salt16, 32)
func DeriveKeyScrypt(passphrase, salt []byte, keyLen int) ([]byte, error) {
key, err := scrypt.Key(passphrase, salt, 32768, 8, 1, keyLen)
if err != nil {
return nil, coreerr.E("crypt.DeriveKeyScrypt", "failed to derive key", err)
}
return key, nil
}
// HKDF derives a key using HKDF-SHA256.
// secret is the input keying material, salt is optional (can be nil),
// info is optional context, and keyLen is the desired output length.
func HKDF(secret, salt, info []byte, keyLen int) ([]byte, error) {
reader := hkdf.New(sha256.New, secret, salt, info)
key := make([]byte, keyLen)
if _, err := io.ReadFull(reader, key); err != nil {
return nil, coreerr.E("crypt.HKDF", "failed to derive key", err)
}
return key, nil
}
// generateSalt creates a random salt of the given length.
func generateSalt(length int) ([]byte, error) {
salt := make([]byte, length)
if _, err := rand.Read(salt); err != nil {
return nil, coreerr.E("crypt.generateSalt", "failed to generate random salt", err)
}
return salt, nil
}