hw::trezor::protocol::crypto::chacha Namespace Reference

Functions
void	decrypt (const void *ciphertext, size_t length, const uint8_t *key, const uint8_t *iv, char *plaintext, size_t *plaintext_len)

Variables
const unsigned	IV_SIZE = 12
const unsigned	TAG_SIZE = 16

Function Documentation

decrypt()

void hw::trezor::protocol::crypto::chacha::decrypt	(	const void *	ciphertext,
		size_t	length,
		const uint8_t *	key,
		const uint8_t *	iv,
		char *	plaintext,
		size_t *	plaintext_len = nullptr )

Chacha20Poly1305 decryption with tag verification. RFC 7539.

Definition at line 120 of file protocol.cpp.

                                                                                                                                    {
    CHECK_AND_ASSERT_THROW_MES(length >= TAG_SIZE, "Ciphertext length too small");
    CHECK_AND_ASSERT_THROW_MES(!plaintext_len || *plaintext_len >= (length - TAG_SIZE), "Plaintext length too small");
 
    unsigned long long int res_len = plaintext_len ? *plaintext_len : length;
    auto r = crypto_aead_chacha20poly1305_ietf_decrypt(
        reinterpret_cast<unsigned char *>(plaintext), &res_len, nullptr,
        static_cast<const unsigned char *>(ciphertext), length, nullptr, 0, iv, key);
 
    if (r != 0){
      throw exc::Poly1305TagInvalid();
    }
 
    if (plaintext_len){
      *plaintext_len = (size_t) res_len;
    }
  }

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Variable Documentation

IV_SIZE

const unsigned hw::trezor::protocol::crypto::chacha::IV_SIZE = 12

Definition at line 96 of file protocol.hpp.

TAG_SIZE

const unsigned hw::trezor::protocol::crypto::chacha::TAG_SIZE = 16

Definition at line 97 of file protocol.hpp.