123 lines
2.5 KiB
Go
123 lines
2.5 KiB
Go
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package secio
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import (
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"errors"
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"fmt"
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"strings"
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"crypto/aes"
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"crypto/cipher"
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"crypto/hmac"
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"crypto/sha1"
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"crypto/sha512"
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"hash"
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ci "github.com/libp2p/go-libp2p-crypto"
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sha256 "github.com/minio/sha256-simd"
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bfish "golang.org/x/crypto/blowfish"
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)
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// SupportedExchanges is the list of supported ECDH curves
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var SupportedExchanges = DefaultSupportedExchanges
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const DefaultSupportedExchanges = "P-256,P-384,P-521"
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// SupportedCiphers is the list of supported Ciphers
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var SupportedCiphers = DefaultSupportedCiphers
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const DefaultSupportedCiphers = "AES-256,AES-128,Blowfish"
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// SupportedHashes is the list of supported Hashes
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var SupportedHashes = DefaultSupportedHashes
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const DefaultSupportedHashes = "SHA256,SHA512"
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// HMAC carries a hash and its size
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type HMAC struct {
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hash.Hash
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size int
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}
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// encParams represent encryption parameters
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type encParams struct {
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// keys
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permanentPubKey ci.PubKey
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ephemeralPubKey []byte
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keys ci.StretchedKeys
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// selections
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curveT string
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cipherT string
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hashT string
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// cipher + mac
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cipher cipher.Stream
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mac HMAC
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}
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func (e *encParams) makeMacAndCipher() error {
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m, err := newMac(e.hashT, e.keys.MacKey)
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if err != nil {
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return err
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}
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bc, err := newBlockCipher(e.cipherT, e.keys.CipherKey)
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if err != nil {
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return err
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}
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e.cipher = cipher.NewCTR(bc, e.keys.IV)
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e.mac = m
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return nil
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}
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func newMac(hashType string, key []byte) (HMAC, error) {
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switch hashType {
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case "SHA1":
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return HMAC{hmac.New(sha1.New, key), sha1.Size}, nil
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case "SHA512":
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return HMAC{hmac.New(sha512.New, key), sha512.Size}, nil
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case "SHA256":
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return HMAC{hmac.New(sha256.New, key), sha256.Size}, nil
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default:
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return HMAC{}, fmt.Errorf("Unrecognized hash type: %s", hashType)
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}
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}
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func newBlockCipher(cipherT string, key []byte) (cipher.Block, error) {
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switch cipherT {
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case "AES-128", "AES-256":
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return aes.NewCipher(key)
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case "Blowfish":
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return bfish.NewCipher(key)
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default:
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return nil, fmt.Errorf("Unrecognized cipher type: %s", cipherT)
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}
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}
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// Determines which algorithm to use. Note: f(a, b) = f(b, a)
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func selectBest(order int, p1, p2 string) (string, error) {
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var f, s []string
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switch {
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case order < 0:
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f = strings.Split(p2, ",")
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s = strings.Split(p1, ",")
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case order > 0:
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f = strings.Split(p1, ",")
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s = strings.Split(p2, ",")
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default: // Exact same preferences.
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p := strings.Split(p1, ",")
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return p[0], nil
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}
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for _, fc := range f {
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for _, sc := range s {
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if fc == sc {
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return fc, nil
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}
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}
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}
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return "", errors.New("No algorithms in common!")
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}
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