Ecc Unicode C Reference Documentation

Ecc

Elliptical Curve Cryptography class for generating ECC keys, computing shared secrets, and creating and verifying ECC signatures. Supports the following curves:

  • secp256r1 (also known as P-256 and prime256v1)
  • secp384r1 (also known as P-384)
  • secp521r1 (also known as P-521)
  • secp256k1 (This is the curve used for Bitcoin)

Additional curves will be supported in the future.

Create/Dispose

HCkEccW CkEccW_Create(void);

Creates an instance of the HCkEccW object and returns a handle (i.e. a "void *" pointer). The handle is passed in the 1st argument for the functions listed on this page.

void CkEccW_Dispose(HCkEccW handle);

Objects created by calling CkEccW_Create must be freed by calling this method. A memory leak occurs if a handle is not disposed by calling this function. Also, any handle returned by a Chilkat "C" function must also be freed by the application by calling the appropriate Dispose method, such as CkEccW_Dispose.

Properties

void CkEccW_getDebugLogFilePath(HCkEccW cHandle, HCkString retval);

void CkEccW_putDebugLogFilePath(HCkEccW cHandle, const wchar_t *newVal);

const wchar_t *CkEccW_debugLogFilePath(HCkEccW cHandle);

If set to a file path, causes each Chilkat method or property call to automatically append it's LastErrorText to the specified log file. The information is appended such that if a hang or crash occurs, it is possible to see the context in which the problem occurred, as well as a history of all Chilkat calls up to the point of the problem. The VerboseLogging property can be set to provide more detailed information.

This property is typically used for debugging the rare cases where a Chilkat method call hangs or generates an exception that halts program execution (i.e. crashes). A hang or crash should generally never happen. The typical causes of a hang are:

  1. a timeout related property was set to 0 to explicitly indicate that an infinite timeout is desired,
  2. the hang is actually a hang within an event callback (i.e. it is a hang within the application code), or
  3. there is an internal problem (bug) in the Chilkat code that causes the hang.

void CkEccW_getLastErrorHtml(HCkEccW cHandle, HCkString retval);

const wchar_t *CkEccW_lastErrorHtml(HCkEccW cHandle);

Provides information in HTML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

void CkEccW_getLastErrorText(HCkEccW cHandle, HCkString retval);

const wchar_t *CkEccW_lastErrorText(HCkEccW cHandle);

Provides information in plain-text format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

Concept of LastErrorText

LastErrorText Standard Information

void CkEccW_getLastErrorXml(HCkEccW cHandle, HCkString retval);

const wchar_t *CkEccW_lastErrorXml(HCkEccW cHandle);

Provides information in XML format about the last method/property called. If a method call returns a value indicating failure, or behaves unexpectedly, examine this property to get more information.

BOOL CkEccW_getLastMethodSuccess(HCkEccW cHandle);

void CkEccW_putLastMethodSuccess(HCkEccW cHandle, BOOL newVal);

Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of TRUE indicates success, a value of FALSE indicates failure. This property is automatically set for method calls. It is not modified by property accesses. The property is automatically set to indicate success for the following types of method calls:

  • Any method that returns a string.
  • Any method returning a Chilkat object, binary bytes, or a date/time.
  • Any method returning a standard boolean status value where success = TRUE and failure = FALSE.
  • Any method returning an integer where failure is defined by a return value less than zero.

Note: Methods that do not fit the above requirements will always set this property equal to TRUE. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

BOOL CkEccW_getVerboseLogging(HCkEccW cHandle);

void CkEccW_putVerboseLogging(HCkEccW cHandle, BOOL newVal);

If set to TRUE, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is FALSE. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

void CkEccW_getVersion(HCkEccW cHandle, HCkString retval);

const wchar_t *CkEccW_version(HCkEccW cHandle);

Version of the component/library, such as "9.5.0.63"

Methods

HCkPrivateKeyW CkEccW_GenEccKey(HCkEccW cHandle, const wchar_t *curveName, HCkPrngW prng);

Introduced in version 9.5.0.52

Generates an ECC private key. The curveName specifies the curve name which determines the key size. The prng provides a source for generating the random private key.

The following curve names are accepted:

  • secp256r1 (also known as P-256 and prime256v1)
  • secp384r1 (also known as P-384)
  • secp521r1 (also known as P-521)
  • secp256k1 (This is the curve used for Bitcoin)

Returns NULL on failure

Generate an ECC Key

HCkPrivateKeyW CkEccW_GenEccKey2(HCkEccW cHandle, const wchar_t *curveName, const wchar_t *encodedK, const wchar_t *encoding);

Introduced in version 9.5.0.55

Generates an ECC private key using a specified value for K. The curveName specifies the curve name which determines the key size. The encodedK is the encoded value of the private key. The encoding is the encoding used for encodedK, which can be "hex", "base64", "decimal", etc.

Note: This method is typically used for testing -- such as when the same private key is desired to produce results identical from run to run.

The following curve names are accepted:

  • secp256r1 (also known as P-256 and prime256v1)
  • secp384r1 (also known as P-384)
  • secp521r1 (also known as P-521)
  • secp256k1 (This is the curve used for Bitcoin)

Returns NULL on failure

Generate ECC Keys using Specified Values for K

BOOL CkEccW_SaveLastError(HCkEccW cHandle, const wchar_t *path);

Saves the last-error information (the contents of LastErrorXml) to an XML formatted file.

Returns TRUE for success, FALSE for failure.

BOOL CkEccW_SharedSecretENC(HCkEccW cHandle, HCkPrivateKeyW privKey, HCkPublicKeyW pubKey, const wchar_t *encoding, const wchar_t *outStr);

const wchar_t *CkEccW_sharedSecretENC(HCkEccW cHandle, HCkPrivateKeyW privKey, HCkPublicKeyW pubKey, const wchar_t *encoding);

Introduced in version 9.5.0.52

Computes a shared secret given a private and public key. For example, Alice and Bob can compute the identical shared secret by doing the following: Alice sends Bob her public key, and Bob calls SharedSecretENC with his private key and Alice's public key. Bob sends Alice his public key, and Alice calls SharedSecretENC with her private key and Bob's public key. Both calls to SharedSecretENC will produce the same result. The resulting bytes are returned in encoded string form (hex, base64, etc) as specified by encoding.

Note: The private and public keys must both be keys on the same ECC curve.

Returns TRUE for success, FALSE for failure.

List of Supported Encodings (Base64, Hex, etc.)

How to Generate an Elliptic Curve Shared Secret

BOOL CkEccW_SignHashENC(HCkEccW cHandle, const wchar_t *encodedHash, const wchar_t *encoding, HCkPrivateKeyW privkey, HCkPrngW prng, const wchar_t *outStr);

const wchar_t *CkEccW_signHashENC(HCkEccW cHandle, const wchar_t *encodedHash, const wchar_t *encoding, HCkPrivateKeyW privkey, HCkPrngW prng);

Introduced in version 9.5.0.52

Computes an ECC signature on a hash. ECC signatures are computed and verified on the hashes of data (such as SHA1, SHA256, etc.). The hash of the data is passed in encodedHash. The encoding, such as "base64", "hex", etc. is passed in encoding. The ECC private key is passed in the 3rd argument (privkey). Given that creating an ECC signature involves the generation of random numbers, a PRNG is passed in the 4th argument (prng). The signature is returned as an encoded string using the encoding specified by the encoding argument.

Returns TRUE for success, FALSE for failure.

List of Supported Encodings (Base64, Hex, etc.)

ECDSA Sign Data and Verify Signature

int CkEccW_VerifyHashENC(HCkEccW cHandle, const wchar_t *encodedHash, const wchar_t *encodedSig, const wchar_t *encoding, HCkPublicKeyW pubkey);

Introduced in version 9.5.0.52

Verifies an ECC signature. ECC signatures are computed and verified on the hashes of data (such as SHA1, SHA256, etc.). The hash of the data is passed in encodedHash. The encoded signature is passed in encodedSig. The encoding of both the hash and signature, such as "base64", "hex", etc. is passed in encoding. The ECC public key is passed in the last argument (pubkey).

The method returns 1 for a valid signature, 0 for an invalid signature, and -1 for any other failure.

List of Supported Encodings (Base64, Hex, etc.)

ECDSA Sign Data and Verify Signature