crypt.c

Purpose

Generic transform layer over codecs, hashes and symmetric/asymmetric crypto.

Direct Helper APIs

uint8_t *XCrypt_AES(const uint8_t *pInput, size_t *pLength, const uint8_t *pKey, size_t nKeyLen, const uint8_t *pIV)

uint8_t *XDecrypt_AES(const uint8_t *pInput, size_t *pLength, const uint8_t *pKey, size_t nKeyLen, const uint8_t *pIV)

• Arguments:
  • pInput: input bytes.
  • pLength: in/out length.
  • pKey: AES key.
  • nKeyLen: key length in bytes.
  • pIV: IV bytes, may be NULL.
• Does:
  • initializes AES-CBC helper with embedded-IV behavior and encrypts/decrypts one payload.
• Returns:
  • allocated output buffer or NULL.

uint8_t *XCrypt_HEX(const uint8_t *pInput, size_t *pLength, const char *pSpace, size_t nColumns, xbool_t bLowCase)

• Arguments:
  • pInput: input bytes.
  • pLength: in/out length.
  • pSpace: optional separator inserted between byte pairs.
  • nColumns: optional wrap width in bytes.
  • bLowCase: lower- or upper-case hex digits.
• Does:
  • renders input bytes as printable hex text.
• Returns:
  • allocated text buffer or NULL.

uint8_t *XDecrypt_HEX(const uint8_t *pInput, size_t *pLength, xbool_t bLowCase)

• Arguments:
  • pInput: hex text.
  • pLength: in/out length.
  • bLowCase: accepted case preference.
• Does:
  • parses hex pairs until parsing fails.
• Returns:
  • allocated decoded bytes or NULL.

uint8_t *XCrypt_XOR(const uint8_t *pInput, size_t nLength, const uint8_t *pKey, size_t nKeyLen)

• Arguments:
  • input bytes and explicit key bytes/length.
• Does:
  • XORs each input byte with a repeating key sequence.
• Returns:
  • allocated output buffer of nLength + 1 or NULL.

char *XCrypt_Reverse(const char *pInput, size_t nLength)

• Arguments:
  • pInput: source text.
  • nLength: byte count to reverse.
• Does:
  • creates a reversed copy.
• Returns:
  • allocated string or NULL.

char *XCrypt_Casear(const char *pInput, size_t nLength, size_t nKey)

char *XDecrypt_Casear(const char *pInput, size_t nLength, size_t nKey)

• Arguments:
  • pInput: source text.
  • nLength: text length.
  • nKey: rotation amount.
• Does:
  • rotates alphabetic ASCII only.
  • non-alphabetic bytes are copied unchanged.
• Returns:
  • allocated string or NULL.

Cipher Identification APIs

xcrypt_chipher_t XCrypt_GetCipher(const char *pCipher)

• Arguments:
  • pCipher: textual cipher name.
• Does:
  • maps text such as aes, hex, base64, sha256, rs256 into enum values.
• Returns:
  • matching enum or XC_INVALID.

const char *XCrypt_GetCipherStr(xcrypt_chipher_t eCipher)

• Arguments:
  • eCipher: cipher enum.
• Does:
  • returns the library’s textual name for that enum.
• Returns:
  • static string or NULL.
• Caveat:
  • XC_HS256 maps to "h256" in current code, not the more expected "hs256".

Context / Chain APIs

void XCrypt_Init(xcrypt_ctx_t *pCtx, xbool_t bDecrypt, char *pCiphers, xcrypt_cb_t callback, void *pUser)

• Arguments:
  • pCtx: destination chain context.
  • bDecrypt: whether caller intends decrypt path.
  • pCiphers: colon-separated cipher chain string.
  • callback: key/IV callback.
  • pUser: user context passed to callback.
• Does:
  • stores configuration into the context.
• Returns:
  • no return value.

uint8_t *XCrypt_Single(xcrypt_ctx_t *pCtx, xcrypt_chipher_t eCipher, const uint8_t *pInput, size_t *pLength)

• Arguments:
  • one configured context, one cipher enum, input bytes and in/out length.
• Does:
  • applies exactly one stage.
  • fetches key/IV via callback when the stage requires them.
  • for hashes and CRC, rewrites *pLength to digest/text length.
• Returns:
  • allocated output buffer or NULL.

uint8_t *XDecrypt_Single(xcrypt_ctx_t *pCtx, xcrypt_chipher_t eCipher, const uint8_t *pInput, size_t *pLength)

• Arguments:
  • same shape as XCrypt_Single.
• Does:
  • runs one reversible stage in decrypt mode.
• Returns:
  • allocated output buffer or NULL.
• Caveat:
  • hash-style ciphers are not reversible and are not supported here.

uint8_t *XCrypt_Multy(xcrypt_ctx_t *pCtx, const uint8_t *pInput, size_t *pLength)

• Arguments:
  • pCtx: initialized context with pCiphers.
  • pInput: source bytes.
  • pLength: in/out length.
• Does:
  • tokenizes pCiphers on :.
  • pipes the output of each stage into the next stage.
  • frees intermediate stage outputs along the way.
• Returns:
  • final allocated output buffer or NULL.

Notes

• Generic hash stages may return printable text rather than raw binary.
• Generic CRC32 output is decimal text, not raw 32-bit binary.