include/u2f.h

// Common U2F raw message format header - Review Draft
// 2014-10-08
// Editor: Jakob Ehrensvard, Yubico, jakob@yubico.com

#ifndef __U2F_H_INCLUDED__
#define __U2F_H_INCLUDED__

#ifdef _MSC_VER  // Windows
typedef unsigned char     uint8_t;
typedef unsigned short    uint16_t;
typedef unsigned int      uint32_t;
typedef unsigned long int uint64_t;
#else
#include <stdint.h>
#endif

#ifdef __cplusplus
extern "C" {
#endif

// General constants

#define U2F_EC_KEY_SIZE         32      // EC key size in bytes
#define U2F_EC_POINT_SIZE       ((U2F_EC_KEY_SIZE * 2) + 1) // Size of EC point
#define U2F_MAX_KH_SIZE         128     // Max size of key handle
#define U2F_MAX_ATT_CERT_SIZE   2048    // Max size of attestation certificate
#define U2F_MAX_EC_SIG_SIZE     72      // Max size of DER coded EC signature
#define U2F_CTR_SIZE            4       // Size of counter field
#define U2F_APPID_SIZE          32      // Size of application id
#define U2F_CHAL_SIZE           32      // Size of challenge
#define U2F_MAX_ATTEST_SIZE     256     // Size of largest blob to sign
#define U2F_P256_SIZE           32
#define U2F_FIXED_KH_SIZE       64      // Size of fixed size key handles

#define ENC_SIZE(x)             ((x + 7) & 0xfff8)

// EC (uncompressed) point

#define U2F_POINT_UNCOMPRESSED  0x04    // Uncompressed point format

typedef struct {
    uint8_t pointFormat;                // Point type
    uint8_t x[U2F_EC_KEY_SIZE];         // X-value
    uint8_t y[U2F_EC_KEY_SIZE];         // Y-value
} U2F_EC_POINT;

// Request Flags.

#define U2F_AUTH_ENFORCE        0x03    // Enforce user presence and sign
#define U2F_AUTH_CHECK_ONLY     0x07    // Check only
#define U2F_AUTH_FLAG_TUP       0x01    // Test of user presence set

// TODO(louiscollard): Add Descriptions.

typedef struct {
    uint8_t appId[U2F_APPID_SIZE];      // Application id
    uint8_t userSecret[U2F_P256_SIZE];
    uint8_t flags;
} U2F_GENERATE_REQ;

typedef struct {
    U2F_EC_POINT pubKey;                   // Generated public key
    uint8_t keyHandle[U2F_FIXED_KH_SIZE];  // Key handle
} U2F_GENERATE_RESP;

typedef struct {
    uint8_t appId[U2F_APPID_SIZE];         // Application id
    uint8_t userSecret[U2F_P256_SIZE];
    uint8_t keyHandle[U2F_FIXED_KH_SIZE];  // Key handle
    uint8_t hash[U2F_P256_SIZE];
    uint8_t flags;
} U2F_SIGN_REQ;

typedef struct {
    uint8_t sig_r[U2F_P256_SIZE];   // Signature
    uint8_t sig_s[U2F_P256_SIZE];   // Signature
} U2F_SIGN_RESP;

typedef struct {
    uint8_t userSecret[U2F_P256_SIZE];
    uint8_t format;
    uint8_t dataLen;
    uint8_t data[U2F_MAX_ATTEST_SIZE];
} U2F_ATTEST_REQ;

typedef struct {
    uint8_t sig_r[U2F_P256_SIZE];
    uint8_t sig_s[U2F_P256_SIZE];
} U2F_ATTEST_RESP;

// Command status responses

#define U2F_SW_NO_ERROR                 0x9000 // SW_NO_ERROR
#define U2F_SW_WRONG_DATA               0x6A80 // SW_WRONG_DATA
#define U2F_SW_CONDITIONS_NOT_SATISFIED 0x6985 // SW_CONDITIONS_NOT_SATISFIED
#define U2F_SW_COMMAND_NOT_ALLOWED      0x6986 // SW_COMMAND_NOT_ALLOWED
#define U2F_SW_INS_NOT_SUPPORTED        0x6D00 // SW_INS_NOT_SUPPORTED

// Protocol extensions

// Non-standardized command status responses
#define U2F_SW_CLA_NOT_SUPPORTED        0x6E00
#define U2F_SW_WRONG_LENGTH             0x6700
#define U2F_SW_WTF                      0x6f00

// Additional flags for P1 field
#define G2F_ATTEST      0x80    // Fixed attestation key
#define G2F_CONSUME     0x02    // Consume presence

// The key handle format was changed when support for user secrets was added.
// U2F_SIGN requests that specify this flag will first try to validate the
// key handle as a new format key handle, and if that fails, will fall back
// to treating it as a legacy key handle (without user secrets).
#define SIGN_LEGACY_KH  0x40

// U2F Attest format for U2F Register Response.
#define U2F_ATTEST_FORMAT_REG_RESP      0

// Vendor command to enable/disable the extensions
#define U2F_VENDOR_MODE U2F_VENDOR_LAST

#ifdef __cplusplus
}
#endif

#endif  // __U2F_H_INCLUDED__