Dsa DataFlex Reference Documentation

Dsa

Current Version: 9.5.0.73

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

// (Dataflex programs use the 32-bit Chilkat ActiveX)
Handle hoDsa
Get Create(RefClass(cComChilkatDsa)) to hoDsa

Properties

DebugLogFilePath
Function ComDebugLogFilePath Returns String
Procedure Set ComDebugLogFilePath String value

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
Function ComGroupSize Returns Integer
Procedure Set ComGroupSize Integer value

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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Hash
Function ComHash Returns Variant
Procedure Set ComHash Variant value

The hash to be signed or verified via the SignHash and Verify methods. In both cases, the Hash should be set prior to calling SignHash or Verify. This property may also be set via the SetEncodedHash method.

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HexG
Function ComHexG Returns String

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
Function ComHexP Returns String

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
Function ComHexQ Returns String

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
Function ComHexX Returns String

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

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HexY
Function ComHexY Returns String

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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LastBinaryResult
Function ComLastBinaryResult Returns Variant
Introduced in version 9.5.0.52

The binary data returned by the last (binary data returning) method called. Only available if Chilkat.Global.KeepBinaryResult is set to True. This provides a means for obtaining large varbinary results in the SQL Server environment (where limitations exist in getting large amounts of data returned by method calls, but where temp tables can be used for binary properties).

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LastErrorHtml
Function ComLastErrorHtml Returns String

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
Function ComLastErrorText Returns String

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
Function ComLastErrorXml Returns String

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
Function ComLastMethodSuccess Returns Boolean
Procedure Set ComLastMethodSuccess Boolean value
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.

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LastStringResult
Function ComLastStringResult Returns String
Introduced in version 9.5.0.52

The string return value of the last (string returning) method called. Only available if Chilkat.Global.KeepStringResult is set to True. This provides a means for obtaining large string results in the SQL Server environment (where limitations exist in getting long strings returned by method calls, but where temp tables can be used for string properties).

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LastStringResultLen
Function ComLastStringResultLen Returns Integer
Introduced in version 9.5.0.53

The length, in characters, of the string contained in the LastStringResult property.

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Signature
Function ComSignature Returns Variant
Procedure Set ComSignature Variant value

The signature created by calling SignHash. If verifying a signature, this may be set prior to calling the Verify method.

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VerboseLogging
Function ComVerboseLogging Returns Boolean
Procedure Set ComVerboseLogging Boolean value

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
Function ComVersion Returns String

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

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Methods

FromDer
Function ComFromDer Variant derData Returns Boolean

Loads a DSA private key from in-memory DSA DER encoded bytes.

Returns True for success, False for failure.

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FromDerFile
Function ComFromDerFile String path Returns Boolean

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

Returns True for success, False for failure.

More Information and Examples
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FromEncryptedPem
Function ComFromEncryptedPem String password String pemData Returns Boolean

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 True for success, False for failure.

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FromPem
Function ComFromPem String pemData Returns Boolean

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

Returns True for success, False for failure.

More Information and Examples
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FromPublicDer
Function ComFromPublicDer Variant derData Returns Boolean

Loads a DSA public key from an in-memory DER-encoded byte array.

Returns True for success, False for failure.

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FromPublicDerFile
Function ComFromPublicDerFile String path Returns Boolean

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

Returns True for success, False for failure.

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FromPublicPem
Function ComFromPublicPem String pemData Returns Boolean

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

Returns True for success, False for failure.

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FromXml
Function ComFromXml String xmlKey Returns Boolean

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

Returns True for success, False for failure.

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GenKey
Function ComGenKey Integer numBits Returns Boolean

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 True for success, False for failure.

More Information and Examples
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GenKeyFromParamsDer
Function ComGenKeyFromParamsDer Variant derBytes Returns Boolean

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

Returns True for success, False for failure.

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GenKeyFromParamsDerFile
Function ComGenKeyFromParamsDerFile String path Returns Boolean

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 True for success, False for failure.

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GenKeyFromParamsPem
Function ComGenKeyFromParamsPem String pem Returns Boolean

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 True for success, False for failure.

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GenKeyFromParamsPemFile
Function ComGenKeyFromParamsPemFile String path Returns Boolean

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 True for success, False for failure.

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GetEncodedHash
Function ComGetEncodedHash String encoding Returns String

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 null on failure

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GetEncodedSignature
Function ComGetEncodedSignature String encoding Returns String

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 null on failure

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LoadText
Function ComLoadText String path Returns String

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 null on failure

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SaveText
Function ComSaveText String strToSave String path Returns Boolean

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

Returns True for success, False for failure.

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SetEncodedHash
Function ComSetEncodedHash String encoding String encodedHash Returns Boolean

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 True for success, False for failure.

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SetEncodedSignature
Function ComSetEncodedSignature String encoding String encodedSig Returns Boolean

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 True for success, False for failure.

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SetEncodedSignatureRS
Function ComSetEncodedSignatureRS String encoding String encodedR String encodedS Returns Boolean

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 True for success, False for failure.

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SetKeyExplicit
Function ComSetKeyExplicit Integer groupSizeInBytes String pHex String qHex String gHex String xHex Returns Boolean

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 True for success, False for failure.

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SetPubKeyExplicit
Function ComSetPubKeyExplicit Integer groupSizeInBytes String pHex String qHex String gHex String yHex Returns Boolean

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 True for success, False for failure.

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SignHash
Function ComSignHash Returns Boolean

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 True, the signature may be retrieved by either calling GetEncodedHash, or by accessing the Signature property.

Returns True for success, False for failure.

More Information and Examples
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ToDer
Function ComToDer Returns Variant

Writes the DSA private key to a DER-encoded byte array.

Returns null on failure

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ToDerFile
Function ComToDerFile String path Returns Boolean

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

Returns True for success, False for failure.

More Information and Examples
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ToEncryptedPem
Function ComToEncryptedPem String password Returns String

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

Returns null on failure

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ToPem
Function ComToPem Returns String

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

Returns null on failure

More Information and Examples
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ToPublicDer
Function ComToPublicDer Returns Variant

Writes the DSA public key to a DER-encoded byte array.

Returns null on failure

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ToPublicDerFile
Function ComToPublicDerFile String path Returns Boolean

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

Returns True for success, False for failure.

More Information and Examples
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ToPublicPem
Function ComToPublicPem Returns String

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

Returns null on failure

More Information and Examples
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ToXml
Function ComToXml Boolean bPublicOnly Returns String

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 null on failure

More Information and Examples
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UnlockComponent
Function ComUnlockComponent String unlockCode Returns Boolean

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

Returns True for success, False for failure.

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Verify
Function ComVerify Returns Boolean

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 True for success, False for failure.

More Information and Examples
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VerifyKey
Function ComVerifyKey Returns Boolean

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

More Information and Examples
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