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Cryptography

API Reference

group bt_crypto

Cryptography.

Functions

int bt_rand(void *buf, size_t len)

Generate random data.

A random number generation helper which utilizes the Bluetooth controller’s own RNG.

Parameters

  • buf – Buffer to insert the random data

  • len – Length of random data to generate

Returns

Zero on success or error code otherwise, positive in case of protocol error or negative (POSIX) in case of stack internal error

int bt_encrypt_le(const uint8_t key[16], const uint8_t plaintext[16], uint8_t enc_data[16])

AES encrypt little-endian data.

An AES encrypt helper is used to request the Bluetooth controller’s own hardware to encrypt the plaintext using the key and returns the encrypted data.

Parameters

  • key – 128 bit LS byte first key for the encryption of the plaintext

  • plaintext – 128 bit LS byte first plaintext data block to be encrypted

  • enc_data – 128 bit LS byte first encrypted data block

Returns

Zero on success or error code otherwise.

int bt_encrypt_be(const uint8_t key[16], const uint8_t plaintext[16], uint8_t enc_data[16])

AES encrypt big-endian data.

An AES encrypt helper is used to request the Bluetooth controller’s own hardware to encrypt the plaintext using the key and returns the encrypted data.

Parameters

  • key – 128 bit MS byte first key for the encryption of the plaintext

  • plaintext – 128 bit MS byte first plaintext data block to be encrypted

  • enc_data – 128 bit MS byte first encrypted data block

Returns

Zero on success or error code otherwise.

int bt_ccm_decrypt(const uint8_t key[16], uint8_t nonce[13], const uint8_t *enc_data, size_t len, const uint8_t *aad, size_t aad_len, uint8_t *plaintext, size_t mic_size)

Decrypt big-endian data with AES-CCM.

Decrypts and authorizes enc_data with AES-CCM, as described in https://tools.ietf.org/html/rfc3610.

Assumes that the MIC follows directly after the encrypted data.

Parameters

  • key – 128 bit MS byte first key

  • nonce – 13 byte MS byte first nonce

  • enc_data – Encrypted data

  • len – Length of the encrypted data

  • aad – Additional input data

  • aad_len – Additional input data length

  • plaintext – Plaintext buffer to place result in

  • mic_size – Size of the trailing MIC (in bytes)

Return values

  • 0 – Successfully decrypted the data.

  • -EINVAL – Invalid parameters.

  • -EBADMSG – Authentication failed.

int bt_ccm_encrypt(const uint8_t key[16], uint8_t nonce[13], const uint8_t *plaintext, size_t len, const uint8_t *aad, size_t aad_len, uint8_t *enc_data, size_t mic_size)

Encrypt big-endian data with AES-CCM.

Encrypts and generates a MIC from plaintext with AES-CCM, as described in https://tools.ietf.org/html/rfc3610.

Places the MIC directly after the encrypted data.

Parameters

  • key – 128 bit MS byte first key

  • nonce – 13 byte MS byte first nonce

  • plaintext – Plaintext buffer to encrypt

  • len – Length of the encrypted data

  • aad – Additional input data

  • aad_len – Additional input data length

  • enc_data – Buffer to place encrypted data in

  • mic_size – Size of the trailing MIC (in bytes)

Return values

  • 0 – Successfully encrypted the data.

  • -EINVAL – Invalid parameters.