Dsa PureBasic Reference Documentation

Dsa

Current Version: 9.5.0.75

The Digital Signature Algorithm (DSA) is a United States Federal Government standard or FIPS for digital signatures. It was proposed by the National Institute of Standards and Technology (NIST) in August 1991 for use in their Digital Signature Standard (DSS).

Object Creation

obj.i = CkDsa::ckCreate()

; Make sure to dispose of the object when finished like this:
CkDsa::ckDispose(obj);

Properties

DebugLogFilePath
Declare.s ckDebugLogFilePath(obj.i)
Declare setCkDebugLogFilePath(obj.i, value.s)

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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GroupSize
Declare.i ckGroupSize(obj.i)
Declare setCkGroupSize(obj.i, value.i)

The group size (in bits) to be used in DSA key generation. The default value is 160 and corresponds to the fact that SHA-1 is used in signature generation. This property setting should not be changed. It exists for future expansion when additional underlying hash algorithms are supported.

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HexG
Declare.s ckHexG(obj.i) ; (read-only)

The "G" part of a public or private DSA key returned as a hex-encoded SSH1-format bignum. The "G" is the generator. DSA key params consist of G, P, and Q.

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HexP
Declare.s ckHexP(obj.i) ; (read-only)

The "P" part of a public or private DSA key returned as a hex-encoded SSH1-format bignum. The "P" is a large prime. DSA key params consist of G, P, and Q.

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HexQ
Declare.s ckHexQ(obj.i) ; (read-only)

The "Q" part of a public or private DSA key returned as a hex-encoded SSH1-format bignum. DSA key params consist of G, P, and Q.

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HexX
Declare.s ckHexX(obj.i) ; (read-only)

The "X" part of a DSA private key returned as a hex-encoded SSH1-format bignum.

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HexY
Declare.s ckHexY(obj.i) ; (read-only)

The "Y" part of a DSA public key returned as a hex-encoded SSH1-format bignum. (The "Y" value is also accessible w/ a private key, but the "X" value is not available in a DSA public key.)

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LastErrorHtml
Declare.s ckLastErrorHtml(obj.i) ; (read-only)

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
Declare.s ckLastErrorText(obj.i) ; (read-only)

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
Declare.s ckLastErrorXml(obj.i) ; (read-only)

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
Declare.i ckLastMethodSuccess(obj.i)
Declare setCkLastMethodSuccess(obj.i, value.i)
Introduced in version 9.5.0.52

Indicate whether the last method call succeeded or failed. A value of 1 indicates success, a value of 0 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 = 1 and failure = 0.
  • 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 1. For example, a method that returns no value (such as a "void" in C++) will technically always succeed.

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VerboseLogging
Declare.i ckVerboseLogging(obj.i)
Declare setCkVerboseLogging(obj.i, value.i)

If set to 1, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. The default value is 0. Verbose logging should only be used for debugging. The potentially large quantity of logged information may adversely affect peformance.

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Version
Declare.s ckVersion(obj.i) ; (read-only)

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

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Methods

FromDerFile
Declare.i ckFromDerFile(obj.i, path.s)

Loads a DSA private key from a DER-encoded file.

Returns 1 for success, 0 for failure.

More Information and Examples
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FromEncryptedPem
Declare.i ckFromEncryptedPem(obj.i, password.s, pemData.s)

Loads a DSA private key from an in-memory encrypted PEM-formatted string. If the PEM passed to this method is unencrypted, the password is ignored and the PEM is simply loaded.

Returns 1 for success, 0 for failure.

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FromPem
Declare.i ckFromPem(obj.i, pemData.s)

Loads a DSA private key from an in-memory unencrypted PEM-formatted string.

Returns 1 for success, 0 for failure.

More Information and Examples
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FromPublicDerFile
Declare.i ckFromPublicDerFile(obj.i, path.s)

Loads a DSA public key from a DER-encoded file.

Returns 1 for success, 0 for failure.

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FromPublicPem
Declare.i ckFromPublicPem(obj.i, pemData.s)

Loads a DSA public-key from an in-memory PEM string.

Returns 1 for success, 0 for failure.

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FromXml
Declare.i ckFromXml(obj.i, xmlKey.s)

Loads a DSA public or private key from an in-memory XML string.

Returns 1 for success, 0 for failure.

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GenKey
Declare.i ckGenKey(obj.i, numBits.l)

Generates a new DSA key that is numBits bits in length. The numBits should be at least 1024 bits and a multiple of 64. Typical values are 1024 and 2048. The newly generated key may be exported by calling one of the To* methods.

Returns 1 for success, 0 for failure.

More Information and Examples
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GenKeyFromParamsDerFile
Declare.i ckGenKeyFromParamsDerFile(obj.i, path.s)

Generates a new DSA key from a DER-format parameters file created by OpenSSL. An example of using OpenSSL to generate DSA parameters in DER format is:

openssl dsaparam -outform DER 1024 < seedData.xml > dsaparam.der
The newly generated key may be exported by calling one of the To* methods.

Returns 1 for success, 0 for failure.

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GenKeyFromParamsPem
Declare.i ckGenKeyFromParamsPem(obj.i, pem.s)

Generates a new DSA key from parameters (PEM formatted string) created by OpenSSL. The newly generated key may be exported by calling one of the To* methods.

Returns 1 for success, 0 for failure.

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GenKeyFromParamsPemFile
Declare.i ckGenKeyFromParamsPemFile(obj.i, path.s)

Generates a new DSA key from a PEM parameters file created by OpenSSL. The newly generated key may be exported by calling one of the To* methods.

OpenSSL provides the ability to generate DSA key parameters. For example:

openssl dsaparam 1024 < seedData.txt > dsaparam.pem

Here is a sample DSA parameters PEM:

-----BEGIN DSA PARAMETERS-----
MIIBHgKBgQCXIAx4XzLVZ5ZqOFzdsYWVyH/6E/mVPw4TgMZS6Wxajnbdn1/CUBzE
RWTUp8SguTSDpjC1Q/nyno0G6Q96VoW+PUXv8qUph8vbSaEdsjYO/8jSfzkGfvsa
cucr1ythfNyk63aZAKzxeutOmsVe77l6pZI96ROjWF5iizuUB4WgmwIVANxM70wH
8iPPYVzPZqtXCB66I2SnAoGAIbW2VYRjRdoA7trJgmnfWakghKwV1WyaYrotqeDE
07/dipp0cNuY0IAJgSmqLHlAkNa2ZNI/c1mNxcwhYzZrnn8CXIqrYmtI33w0PYCx
KHPqj7puhddFwYS/rFiyWAN0jtCMHlfCVzFGbSzach5QQraPV9YApJXy+ORJ8VPU
/zo=
-----END DSA PARAMETERS-----

Returns 1 for success, 0 for failure.

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GetEncodedHash
Declare.s ckGetEncodedHash(obj.i, encoding.s)

Returns the bytes of the Hash property as a hex or base64 encoded string. The encoding should be set to either "hex" or "base64".

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

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GetEncodedSignature
Declare.s ckGetEncodedSignature(obj.i, encoding.s)

Returns the bytes of the Signature property as a hex or base64 encoded string. The encoding should be set to either "hex" or "base64". The Signature property is set when SignHash is called.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

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LoadText
Declare.s ckLoadText(obj.i, path.s)

Convenience method to load the entire contents of a text file into a string. It is assumed that the text contains ANSI encoded character data.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

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SaveLastError
Declare.i ckSaveLastError(obj.i, path.s)

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

Returns 1 for success, 0 for failure.

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SaveText
Declare.i ckSaveText(obj.i, strToSave.s, path.s)

Convenience method to save a string to a text file. The text is saved using the ANSI character encoding.

Returns 1 for success, 0 for failure.

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SetEncodedHash
Declare.i ckSetEncodedHash(obj.i, encoding.s, encodedHash.s)

Provides a way to set the Hash property by passing an encoded string. The encoding can be "hex" or "base64". The encodedHash contains the encoded bytes of the hash that will be signed or verified via the SignHash and Verify methods.

Returns 1 for success, 0 for failure.

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SetEncodedSignature
Declare.i ckSetEncodedSignature(obj.i, encoding.s, encodedSig.s)

Sets the bytes of the Signature property. (The signature must be specified prior to calling the Verify method.) This method allows for the signature to be set via a hex or base64 encoded string. The encoding should be set to either "hex" or "base64".

Returns 1 for success, 0 for failure.

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SetEncodedSignatureRS
Declare.i ckSetEncodedSignatureRS(obj.i, encoding.s, encodedR.s, encodedS.s)

Sets the bytes of the Signature property by providing the R and S values in encoded form. (The signature must be specified prior to calling the Verify method.) The R and S values may be set via a hex or base64 encoded string. The encoding should be set to either "hex" or "base64".

Returns 1 for success, 0 for failure.

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SetKeyExplicit
Declare.i ckSetKeyExplicit(obj.i, groupSizeInBytes.l, pHex.s, qHex.s, gHex.s, xHex.s)

Sets the DSA object's private key from explicitly provided pHex, qHex, gHex, and xHex values. The groupSizeInBytes specifies the group size (in bytes). It is typically equal to 20, which is the length of the underlying hash function (SHA-1) for signing. The pHex, qHex, gHex, and xHex values are hex-encoded SSH1-format bignums.

Returns 1 for success, 0 for failure.

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SetPubKeyExplicit
Declare.i ckSetPubKeyExplicit(obj.i, groupSizeInBytes.l, pHex.s, qHex.s, gHex.s, yHex.s)

Sets the DSA object's private key from explicitly provided pHex, qHex, gHex, and yHex values. The groupSizeInBytes specifies the group size (in bytes). It is typically equal to 20, which is the length of the underlying hash function (SHA-1) for signing. The pHex, qHex, gHex, and yHex values are hex-encoded SSH1-format bignums.

Returns 1 for success, 0 for failure.

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SignHash
Declare.i ckSignHash(obj.i)

Signs a hash using the digital signature algorithm. Before calling this method, set the hash to be signed by either calling SetEncodedHash or by setting the Hash property. If SignHash returns 1, the signature may be retrieved by either calling GetEncodedHash, or by accessing the Signature property.

Returns 1 for success, 0 for failure.

More Information and Examples
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ToDerFile
Declare.i ckToDerFile(obj.i, path.s)

Writes the DSA private key to a DER-format file.

Returns 1 for success, 0 for failure.

More Information and Examples
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ToEncryptedPem
Declare.s ckToEncryptedPem(obj.i, password.s)

Writes the DSA private key to an in-memory encrypted PEM string.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

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ToPem
Declare.s ckToPem(obj.i)

Writes the DSA private key to an in-memory PEM string.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

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ToPublicDerFile
Declare.i ckToPublicDerFile(obj.i, path.s)

Writes the DSA public key to a DER-format file.

Returns 1 for success, 0 for failure.

More Information and Examples
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ToPublicPem
Declare.s ckToPublicPem(obj.i)

Writes the DSA public key to an in-memory PEM string.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

More Information and Examples
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ToXml
Declare.s ckToXml(obj.i, bPublicOnly.l)

Writes the DSA private or public key to an in-memory XML string. The bPublicOnly determines whether the public or private key is written.

Returns an empty string on failure. Use the LastMethodSuccess property to check for success.

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UnlockComponent
Declare.i ckUnlockComponent(obj.i, unlockCode.s)

Unlocks the component. This must be called once prior to calling any other method.

Returns 1 for success, 0 for failure.

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Verify
Declare.i ckVerify(obj.i)

Verifies a DSA signature. The Hash and Signature properties must be set prior to calling this method. (These properties may also be set via the SetEncodedHash and SetEncodedSignature methods.)

Returns 1 for success, 0 for failure.

More Information and Examples
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VerifyKey
Declare.i ckVerifyKey(obj.i)

Verifies that the public or private key contained in the calling Dsa object is valid. Returns 1 if valid, otherwise returns 0.

More Information and Examples
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