Ecc Unicode C Reference Documentation

Ecc

Current Version: 9.5.0.97

Elliptical Curve Cryptography class for generating ECDSA keys, computing shared secrets, and creating and verifying ECDSA 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)
  • secp192r1
  • secp224r1
  • brainpoolP160r1
  • brainpoolP192r1
  • brainpoolP192r1
  • brainpoolP224r1
  • brainpoolP256r1
  • brainpoolP320r1
  • brainpoolP384r1
  • brainpoolP512r1

Additional curves will be supported in the future.

Create/Dispose

HCkEccW instance = CkEccW_Create();
// ...
CkEccW_Dispose(instance);
HCkEccW CkEccW_Create(void);

Creates an instance of the HCkEccW object and returns a handle ("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

AsnFormat
BOOL CkEccW_getAsnFormat(HCkEccW cHandle);
void CkEccW_putAsnFormat(HCkEccW cHandle, BOOL newVal);
Introduced in version 9.5.0.97

If TRUE, the ECDSA signatures produced by this object will use ASN.1 format. Otherwise the ECDSA signature will be a concatenation of the two raw byte arrays for r and s.

ECDSA signatures have two equal sized parts, r and s. There are two common formats for encoding the signature:

(a) Concatenating the raw byte array of r and s
(b) Encoding both into a structured ASN.1 / DER sequence.

The default value of this property is TRUE, which is to use ASN.1, which is the behavior of earlier versions of Chilkat before this property was added.

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DebugLogFilePath
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.

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LastErrorHtml
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.

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LastErrorText
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.

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LastErrorXml
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.

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LastMethodSuccess
BOOL CkEccW_getLastMethodSuccess(HCkEccW cHandle);
void CkEccW_putLastMethodSuccess(HCkEccW cHandle, BOOL newVal);

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.

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VerboseLogging
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.

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Version
void CkEccW_getVersion(HCkEccW cHandle, HCkString retval);
const wchar_t *CkEccW_version(HCkEccW cHandle);

Version of the component/library, such as "9.5.0.94"

More Information and Examples
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Methods

GenEccKey
HCkPrivateKeyW CkEccW_GenEccKey(HCkEccW cHandle, const wchar_t *curveName, HCkPrngW prng);
Introduced in version 9.5.0.52

Generates an ECDSA 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)
  • secp192r1
  • secp224r1
  • brainpoolP160r1
  • brainpoolP192r1
  • brainpoolP192r1
  • brainpoolP224r1
  • brainpoolP256r1
  • brainpoolP320r1
  • brainpoolP384r1
  • brainpoolP512r1

Returns NULL on failure

More Information and Examples
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GenEccKey2
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 ECDSA 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)
  • secp192r1
  • secp224r1
  • brainpoolP160r1
  • brainpoolP192r1
  • brainpoolP192r1
  • brainpoolP224r1
  • brainpoolP256r1
  • brainpoolP320r1
  • brainpoolP384r1
  • brainpoolP512r1

Returns NULL on failure

More Information and Examples
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SharedSecretENC
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 ECDSA curve.

Returns TRUE for success, FALSE for failure.

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SignBd
BOOL CkEccW_SignBd(HCkEccW cHandle, HCkBinDataW bdData, const wchar_t *hashAlg, const wchar_t *encoding, HCkPrivateKeyW privKey, HCkPrngW prng, const wchar_t *outStr);
const wchar_t *CkEccW_signBd(HCkEccW cHandle, HCkBinDataW bdData, const wchar_t *hashAlg, const wchar_t *encoding, HCkPrivateKeyW privKey, HCkPrngW prng);
Introduced in version 9.5.0.85

This method is the same as SignHashENC, except the actual data to be signed and the name of the hash algorithm is passed in. The following hash algorithms are supported: sha256, sha384, and sha512.

Returns TRUE for success, FALSE for failure.

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SignBdUsingCert
BOOL CkEccW_SignBdUsingCert(HCkEccW cHandle, HCkBinDataW bdData, const wchar_t *hashAlg, const wchar_t *encoding, HCkCertW cert, const wchar_t *outStr);
const wchar_t *CkEccW_signBdUsingCert(HCkEccW cHandle, HCkBinDataW bdData, const wchar_t *hashAlg, const wchar_t *encoding, HCkCertW cert);
Introduced in version 9.5.0.91

Same as SignBd, but instead uses the private key of a certificate (assuming the cert's private key is ECDSA).

Returns TRUE for success, FALSE for failure.

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SignHashENC
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 ECDSA signature on a hash. ECDSA 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 ECDSA private key is passed in the 3rd argument (privkey). Given that creating an ECDSA 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.

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VerifyBd
int CkEccW_VerifyBd(HCkEccW cHandle, HCkBinDataW bdData, const wchar_t *hashAlg, const wchar_t *encodedSig, const wchar_t *encoding, HCkPublicKeyW pubkey);
Introduced in version 9.5.0.85

This method is the same as VerifyHashENC, except the actual data to be verified and the name of the hash algorithm is passed in. The following hash algorithms are supported: sha256, sha384, and sha512.

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VerifyHashENC
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 ECDSA signature. ECDSA 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 ECDSA 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.

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