chore: vendor

vendor/github.com/ProtonMail/go-crypto/openpgp/packet/config.go

@@ -0,0 +1,248 @@
+// Copyright 2012 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package packet
+
+import (
+	"crypto"
+	"crypto/rand"
+	"io"
+	"math/big"
+	"time"
+
+	"github.com/ProtonMail/go-crypto/openpgp/s2k"
+)
+
+// Config collects a number of parameters along with sensible defaults.
+// A nil *Config is valid and results in all default values.
+type Config struct {
+	// Rand provides the source of entropy.
+	// If nil, the crypto/rand Reader is used.
+	Rand io.Reader
+	// DefaultHash is the default hash function to be used.
+	// If zero, SHA-256 is used.
+	DefaultHash crypto.Hash
+	// DefaultCipher is the cipher to be used.
+	// If zero, AES-128 is used.
+	DefaultCipher CipherFunction
+	// Time returns the current time as the number of seconds since the
+	// epoch. If Time is nil, time.Now is used.
+	Time func() time.Time
+	// DefaultCompressionAlgo is the compression algorithm to be
+	// applied to the plaintext before encryption. If zero, no
+	// compression is done.
+	DefaultCompressionAlgo CompressionAlgo
+	// CompressionConfig configures the compression settings.
+	CompressionConfig *CompressionConfig
+	// S2K (String to Key) config, used for key derivation in the context of secret key encryption
+	// and password-encrypted data.
+	// If nil, the default configuration is used
+	S2KConfig *s2k.Config
+	// Iteration count for Iterated S2K (String to Key).
+	// Only used if sk2.Mode is nil.
+	// This value is duplicated here from s2k.Config for backwards compatibility.
+	// It determines the strength of the passphrase stretching when
+	// the said passphrase is hashed to produce a key. S2KCount
+	// should be between 65536 and 65011712, inclusive. If Config
+	// is nil or S2KCount is 0, the value 16777216 used. Not all
+	// values in the above range can be represented. S2KCount will
+	// be rounded up to the next representable value if it cannot
+	// be encoded exactly. When set, it is strongly encrouraged to
+	// use a value that is at least 65536. See RFC 4880 Section
+	// 3.7.1.3.
+	//
+	// Deprecated: SK2Count should be configured in S2KConfig instead.
+	S2KCount int
+	// RSABits is the number of bits in new RSA keys made with NewEntity.
+	// If zero, then 2048 bit keys are created.
+	RSABits int
+	// The public key algorithm to use - will always create a signing primary
+	// key and encryption subkey.
+	Algorithm PublicKeyAlgorithm
+	// Some known primes that are optionally prepopulated by the caller
+	RSAPrimes []*big.Int
+	// Curve configures the desired packet.Curve if the Algorithm is PubKeyAlgoECDSA,
+	// PubKeyAlgoEdDSA, or PubKeyAlgoECDH. If empty Curve25519 is used.
+	Curve Curve
+	// AEADConfig configures the use of the new AEAD Encrypted Data Packet,
+	// defined in the draft of the next version of the OpenPGP specification.
+	// If a non-nil AEADConfig is passed, usage of this packet is enabled. By
+	// default, it is disabled. See the documentation of AEADConfig for more
+	// configuration options related to AEAD.
+	// **Note: using this option may break compatibility with other OpenPGP
+	// implementations, as well as future versions of this library.**
+	AEADConfig *AEADConfig
+	// V5Keys configures version 5 key generation. If false, this package still
+	// supports version 5 keys, but produces version 4 keys.
+	V5Keys bool
+	// "The validity period of the key.  This is the number of seconds after
+	// the key creation time that the key expires.  If this is not present
+	// or has a value of zero, the key never expires.  This is found only on
+	// a self-signature.""
+	// https://tools.ietf.org/html/rfc4880#section-5.2.3.6
+	KeyLifetimeSecs uint32
+	// "The validity period of the signature.  This is the number of seconds
+	// after the signature creation time that the signature expires.  If
+	// this is not present or has a value of zero, it never expires."
+	// https://tools.ietf.org/html/rfc4880#section-5.2.3.10
+	SigLifetimeSecs uint32
+	// SigningKeyId is used to specify the signing key to use (by Key ID).
+	// By default, the signing key is selected automatically, preferring
+	// signing subkeys if available.
+	SigningKeyId uint64
+	// SigningIdentity is used to specify a user ID (packet Signer's User ID, type 28)
+	// when producing a generic certification signature onto an existing user ID.
+	// The identity must be present in the signer Entity.
+	SigningIdentity string
+	// InsecureAllowUnauthenticatedMessages controls, whether it is tolerated to read
+	// encrypted messages without Modification Detection Code (MDC).
+	// MDC is mandated by the IETF OpenPGP Crypto Refresh draft and has long been implemented
+	// in most OpenPGP implementations. Messages without MDC are considered unnecessarily
+	// insecure and should be prevented whenever possible.
+	// In case one needs to deal with messages from very old OpenPGP implementations, there
+	// might be no other way than to tolerate the missing MDC. Setting this flag, allows this
+	// mode of operation. It should be considered a measure of last resort.
+	InsecureAllowUnauthenticatedMessages bool
+	// KnownNotations is a map of Notation Data names to bools, which controls
+	// the notation names that are allowed to be present in critical Notation Data
+	// signature subpackets.
+	KnownNotations map[string]bool
+	// SignatureNotations is a list of Notations to be added to any signatures.
+	SignatureNotations []*Notation
+}
+
+func (c *Config) Random() io.Reader {
+	if c == nil || c.Rand == nil {
+		return rand.Reader
+	}
+	return c.Rand
+}
+
+func (c *Config) Hash() crypto.Hash {
+	if c == nil || uint(c.DefaultHash) == 0 {
+		return crypto.SHA256
+	}
+	return c.DefaultHash
+}
+
+func (c *Config) Cipher() CipherFunction {
+	if c == nil || uint8(c.DefaultCipher) == 0 {
+		return CipherAES128
+	}
+	return c.DefaultCipher
+}
+
+func (c *Config) Now() time.Time {
+	if c == nil || c.Time == nil {
+		return time.Now().Truncate(time.Second)
+	}
+	return c.Time().Truncate(time.Second)
+}
+
+// KeyLifetime returns the validity period of the key.
+func (c *Config) KeyLifetime() uint32 {
+	if c == nil {
+		return 0
+	}
+	return c.KeyLifetimeSecs
+}
+
+// SigLifetime returns the validity period of the signature.
+func (c *Config) SigLifetime() uint32 {
+	if c == nil {
+		return 0
+	}
+	return c.SigLifetimeSecs
+}
+
+func (c *Config) Compression() CompressionAlgo {
+	if c == nil {
+		return CompressionNone
+	}
+	return c.DefaultCompressionAlgo
+}
+
+func (c *Config) RSAModulusBits() int {
+	if c == nil || c.RSABits == 0 {
+		return 2048
+	}
+	return c.RSABits
+}
+
+func (c *Config) PublicKeyAlgorithm() PublicKeyAlgorithm {
+	if c == nil || c.Algorithm == 0 {
+		return PubKeyAlgoRSA
+	}
+	return c.Algorithm
+}
+
+func (c *Config) CurveName() Curve {
+	if c == nil || c.Curve == "" {
+		return Curve25519
+	}
+	return c.Curve
+}
+
+// Deprecated: The hash iterations should now be queried via the S2K() method.
+func (c *Config) PasswordHashIterations() int {
+	if c == nil || c.S2KCount == 0 {
+		return 0
+	}
+	return c.S2KCount
+}
+
+func (c *Config) S2K() *s2k.Config {
+	if c == nil {
+		return nil
+	}
+	// for backwards compatibility
+	if c != nil && c.S2KCount > 0 && c.S2KConfig == nil {
+		return &s2k.Config{
+			S2KCount: c.S2KCount,
+		}
+	}
+	return c.S2KConfig
+}
+
+func (c *Config) AEAD() *AEADConfig {
+	if c == nil {
+		return nil
+	}
+	return c.AEADConfig
+}
+
+func (c *Config) SigningKey() uint64 {
+	if c == nil {
+		return 0
+	}
+	return c.SigningKeyId
+}
+
+func (c *Config) SigningUserId() string {
+	if c == nil {
+		return ""
+	}
+	return c.SigningIdentity
+}
+
+func (c *Config) AllowUnauthenticatedMessages() bool {
+	if c == nil {
+		return false
+	}
+	return c.InsecureAllowUnauthenticatedMessages
+}
+
+func (c *Config) KnownNotation(notationName string) bool {
+	if c == nil {
+		return false
+	}
+	return c.KnownNotations[notationName]
+}
+
+func (c *Config) Notations() []*Notation {
+	if c == nil {
+		return nil
+	}
+	return c.SignatureNotations
+}