package securemessage

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A convenience proto for encoding Diffie-Hellman public keys, for use only when Elliptic Curve based key exchanges are not possible. (Note that the group parameters must be specified separately)

Used in: GenericPublicKey

• required bytes y = 1

  Big-endian two's complement encoded group element

A convenience proto for encoding NIST P-256 elliptic curve public keys

Used in: GenericPublicKey

• required bytes x = 1

  x and y are encoded in big-endian two's complement (slightly wasteful) Client MUST verify (x,y) is a valid point on NIST P256

• required bytes y = 2

Supported encryption schemes

Used in: Header

• NONE = 1

  No encryption

• AES_256_CBC = 2

Used in: securegcm.InitiatorHello, securegcm.ResponderHello

• required PublicKeyType type = 1

• optional EcP256PublicKey ec_p256_public_key = 2

• optional SimpleRsaPublicKey rsa2048_public_key = 3

• optional DhPublicKey dh2048_public_key = 4

  Use only as a last resort

Used in: HeaderAndBody

• required SigScheme signature_scheme = 1

• required EncScheme encryption_scheme = 2

• optional bytes verification_key_id = 3

  Identifies the verification key

• optional bytes decryption_key_id = 4

  Identifies the decryption key

• optional bytes iv = 5

  Encryption may use an IV

• optional bytes public_metadata = 6

  Arbitrary per-protocol public data, to be sent with the plain-text header

• optional uint32 associated_data_length = 7

  The length of some associated data this is not sent in this SecureMessage, but which will be bound to the signature.

• required Header header = 1

  Public data about this message (to be bound in the signature)

• required bytes body = 2

  Payload data

Must be kept wire-format compatible with HeaderAndBody. Provides the SecureMessage code with a consistent wire-format representation that remains stable irrespective of protobuf implementation choices. This low-level representation of a HeaderAndBody should not be used by any code outside of the SecureMessage library implementation/tests.

• required bytes header = 1

  A raw (wire-format) byte encoding of a Header, suitable for hashing

• required bytes body = 2

  Payload data

A list of supported public key types

Used in: GenericPublicKey

• EC_P256 = 1

• RSA2048 = 2

• DH2048_MODP = 3

  2048-bit MODP group 14, from RFC 3526

• required bytes header_and_body = 1

  Must contain a HeaderAndBody message

• required bytes signature = 2

  Signature of header_and_body

Supported "signature" schemes (both symmetric key and public key based)

Used in: Header

• HMAC_SHA256 = 1

• ECDSA_P256_SHA256 = 2

• RSA2048_SHA256 = 3

  Not recommended -- use ECDSA_P256_SHA256 instead

A convenience proto for encoding RSA public keys with small exponents

Used in: GenericPublicKey

• required bytes n = 1

  Encoded in big-endian two's complement

• optional int32 e = 2