algs.go

// Copyright (c) HashiCorp, Inc.
// SPDX-License-Identifier: MPL-2.0

package jwt

import "fmt"

// Alg represents asymmetric signing algorithms
type Alg string

const (
	// JOSE asymmetric signing algorithm values as defined by RFC 7518.
	//
	// See: https://tools.ietf.org/html/rfc7518#section-3.1
	RS256 Alg = "RS256" // RSASSA-PKCS-v1.5 using SHA-256
	RS384 Alg = "RS384" // RSASSA-PKCS-v1.5 using SHA-384
	RS512 Alg = "RS512" // RSASSA-PKCS-v1.5 using SHA-512
	ES256 Alg = "ES256" // ECDSA using P-256 and SHA-256
	ES384 Alg = "ES384" // ECDSA using P-384 and SHA-384
	ES512 Alg = "ES512" // ECDSA using P-521 and SHA-512
	PS256 Alg = "PS256" // RSASSA-PSS using SHA256 and MGF1-SHA256
	PS384 Alg = "PS384" // RSASSA-PSS using SHA384 and MGF1-SHA384
	PS512 Alg = "PS512" // RSASSA-PSS using SHA512 and MGF1-SHA512
	EdDSA Alg = "EdDSA" // Ed25519 using SHA-512
)

var supportedAlgorithms = map[Alg]bool{
	RS256: true,
	RS384: true,
	RS512: true,
	ES256: true,
	ES384: true,
	ES512: true,
	PS256: true,
	PS384: true,
	PS512: true,
	EdDSA: true,
}

// SupportedSigningAlgorithm returns an error if any of the given Algs
// are not supported signing algorithms.
func SupportedSigningAlgorithm(algs ...Alg) error {
	for _, a := range algs {
		if !supportedAlgorithms[a] {
			return fmt.Errorf("unsupported signing algorithm %q", a)
		}
	}
	return nil
}