Function hashForServerKeyExchange

key_agreement.go:133–153

hashForServerKeyExchange hashes the given slices and returns their digest using the given hash function (for TLS 1.2) or using a default based on the sigType (for earlier TLS versions). For Ed25519 signatures, which don't do pre-hashing, it returns the concatenation of the slices.

(sigType uint8, hashFunc crypto.Hash, version uint16, slices ...[]byte)

// the sigType (for earlier TLS versions). For Ed25519 signatures, which don't
// do pre-hashing, it returns the concatenation of the slices.
func hashForServerKeyExchange(sigType uint8, hashFunc crypto.Hash, version uint16, slices ...[]byte) []byte {
	if sigType == signatureEd25519 {
		var signed []byte
		for _, slice := range slices {
			signed = append(signed, slice...)
		}
		return signed
	}
	if version >= VersionTLS12 {
		h := hashFunc.New()
		for _, slice := range slices {
			h.Write(slice)
		}
		digest := h.Sum(nil)
		return digest
	}
	if sigType == signatureECDSA {
		return sha1Hash(slices)
	}
	return md5SHA1Hash(slices)
}

// ecdheKeyAgreement implements a TLS key agreement where the server
// generates an ephemeral EC public/private key pair and signs it. The