aead

Documentation

Overview

Package aead provides subtle implementations of the AEAD primitive.

Index

• Constants
• func ValidateAESKeySize(sizeInBytes uint32) error
• type AESCTR
  • func NewAESCTR(key []byte, ivSize int) (*AESCTR, error)
  • func (a *AESCTR) Decrypt(ciphertext []byte) ([]byte, error)
  • func (a *AESCTR) Encrypt(plaintext []byte) ([]byte, error)
• type AESGCM
  • func NewAESGCM(key []byte) (*AESGCM, error)
  • func (a *AESGCM) Decrypt(ct, aad []byte) ([]byte, error)
  • func (a *AESGCM) Encrypt(pt, aad []byte) ([]byte, error)
• type ChaCha20Poly1305
  • func NewChaCha20Poly1305(key []byte) (*ChaCha20Poly1305, error)
  • func (ca *ChaCha20Poly1305) Decrypt(ct []byte, aad []byte) ([]byte, error)
  • func (ca *ChaCha20Poly1305) Encrypt(pt []byte, aad []byte) ([]byte, error)
• type EncryptThenAuthenticate
  • func NewEncryptThenAuthenticate(indCPACipher INDCPACipher, mac tink.MAC, tagSize int) (*EncryptThenAuthenticate, error)
  • func (e *EncryptThenAuthenticate) Decrypt(ciphertext, additionalData []byte) ([]byte, error)
  • func (e *EncryptThenAuthenticate) Encrypt(plaintext, additionalData []byte) ([]byte, error)
• type INDCPACipher
• type XChaCha20Poly1305
  • func NewXChaCha20Poly1305(key []byte) (*XChaCha20Poly1305, error)
  • func (x *XChaCha20Poly1305) Decrypt(ct []byte, aad []byte) ([]byte, error)
  • func (x *XChaCha20Poly1305) Encrypt(pt []byte, aad []byte) ([]byte, error)

Constants

const (
	// AESGCMIVSize is the only IV size that this implementation supports.
	AESGCMIVSize = 12
	// AESGCMTagSize is the only tag size that this implementation supports.
	AESGCMTagSize = 16
)

const (
	// AESCTRMinIVSize is the minimum IV size that this implementation supports.
	AESCTRMinIVSize = 12
)

Functions

func ValidateAESKeySize

func ValidateAESKeySize(sizeInBytes uint32) error

ValidateAESKeySize checks if the given key size is a valid AES key size.

Types

type AESCTR

type AESCTR struct {
	Key    []byte
	IVSize int
}

AESCTR is an implementation of AEAD interface.

func NewAESCTR

func NewAESCTR(key []byte, ivSize int) (*AESCTR, error)

NewAESCTR returns an AESCTR instance. The key argument should be the AES key, either 16 or 32 bytes to select AES-128 or AES-256. ivSize specifies the size of the IV in bytes.

func (*AESCTR) Decrypt

func (a *AESCTR) Decrypt(ciphertext []byte) ([]byte, error)

Decrypt decrypts ciphertext.

func (*AESCTR) Encrypt

func (a *AESCTR) Encrypt(plaintext []byte) ([]byte, error)

Encrypt encrypts plaintext using AES in CTR mode. The resulting ciphertext consists of two parts: (1) the IV used for encryption and (2) the actual ciphertext.

type AESGCM

type AESGCM struct {
	Key []byte
}

AESGCM is an implementation of AEAD interface.

func NewAESGCM

func NewAESGCM(key []byte) (*AESGCM, error)

NewAESGCM returns an AESGCM instance. The key argument should be the AES key, either 16 or 32 bytes to select AES-128 or AES-256.

func (*AESGCM) Decrypt

func (a *AESGCM) Decrypt(ct, aad []byte) ([]byte, error)

Decrypt decrypts ct with aad as the additionalauthenticated data.

func (*AESGCM) Encrypt

func (a *AESGCM) Encrypt(pt, aad []byte) ([]byte, error)

Encrypt encrypts pt with aad as additional authenticated data. The resulting ciphertext consists of two parts: (1) the IV used for encryption and (2) the actual ciphertext.

Note: AES-GCM implementation of crypto library always returns ciphertext with 128-bit tag.

type ChaCha20Poly1305

type ChaCha20Poly1305 struct {
	Key []byte
}

ChaCha20Poly1305 is an implementation of AEAD interface.

func NewChaCha20Poly1305

func NewChaCha20Poly1305(key []byte) (*ChaCha20Poly1305, error)

NewChaCha20Poly1305 returns an ChaCha20Poly1305 instance. The key argument should be a 32-bytes key.

func (*ChaCha20Poly1305) Decrypt

func (ca *ChaCha20Poly1305) Decrypt(ct []byte, aad []byte) ([]byte, error)

Decrypt decrypts {@code ct} with {@code aad} as the additionalauthenticated data.

func (*ChaCha20Poly1305) Encrypt

func (ca *ChaCha20Poly1305) Encrypt(pt []byte, aad []byte) ([]byte, error)

Encrypt encrypts {@code pt} with {@code aad} as additional authenticated data. The resulting ciphertext consists of two parts: (1) the nonce used for encryption and (2) the actual ciphertext.

type EncryptThenAuthenticate

type EncryptThenAuthenticate struct {
	// contains filtered or unexported fields
}

EncryptThenAuthenticate performs an encrypt-then-MAC operation on plaintext and additional authenticated data (aad). The MAC is computed over (aad || ciphertext || size of aad). This implementation is based on http://tools.ietf.org/html/draft-mcgrew-aead-aes-cbc-hmac-sha2-05.

func NewEncryptThenAuthenticate

func NewEncryptThenAuthenticate(indCPACipher INDCPACipher, mac tink.MAC, tagSize int) (*EncryptThenAuthenticate, error)

NewEncryptThenAuthenticate returns a new instance of EncryptThenAuthenticate.

func (*EncryptThenAuthenticate) Decrypt

func (e *EncryptThenAuthenticate) Decrypt(ciphertext, additionalData []byte) ([]byte, error)

Decrypt decrypts ciphertext with additionalData as additional authenticated data.

func (*EncryptThenAuthenticate) Encrypt

func (e *EncryptThenAuthenticate) Encrypt(plaintext, additionalData []byte) ([]byte, error)

Encrypt encrypts plaintext with additionalData as additional authenticated data. The resulting ciphertext allows for checking authenticity and integrity of additional data, but does not guarantee its secrecy.

The plaintext is encrypted with an INDCPACipher, then MAC is computed over (additionalData || ciphertext || n) where n is additionalData's length in bits represented as a 64-bit bigendian unsigned integer. The final ciphertext format is (IND-CPA ciphertext || mac).

type INDCPACipher

type INDCPACipher interface {
	// Encrypt encrypts plaintext. The resulting ciphertext is indistinguishable under
	// chosen-plaintext attack. However, it does not have integrity protection.
	Encrypt(plaintext []byte) ([]byte, error)

	// Decrypt decrypts ciphertext and returns the resulting plaintext.
	Decrypt(ciphertext []byte) ([]byte, error)
}

INDCPACipher provides an interface for symmetric key ciphers that are indistinguishable against chosen-plaintext attacks. Said primitives do not provide authentication, thus should not be used directly, but only to construct safer primitives such as AEAD.

type XChaCha20Poly1305

type XChaCha20Poly1305 struct {
	Key []byte
}

XChaCha20Poly1305 is an implementation of AEAD interface.

func NewXChaCha20Poly1305

func NewXChaCha20Poly1305(key []byte) (*XChaCha20Poly1305, error)

NewXChaCha20Poly1305 returns an XChaCha20Poly1305 instance. The key argument should be a 32-bytes key.

func (*XChaCha20Poly1305) Decrypt

func (x *XChaCha20Poly1305) Decrypt(ct []byte, aad []byte) ([]byte, error)

Decrypt decrypts {@code ct} with {@code aad} as the additionalauthenticated data.

func (*XChaCha20Poly1305) Encrypt

func (x *XChaCha20Poly1305) Encrypt(pt []byte, aad []byte) ([]byte, error)

Encrypt encrypts {@code pt} with {@code aad} as additional authenticated data. The resulting ciphertext consists of two parts: (1) the nonce used for encryption and (2) the actual ciphertext.