Dsa Xojo Plugin 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

Dim dsa As New Chilkat.Dsa

Properties

DebugLogFilePath
DebugLogFilePath As String

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
GroupSize As Int32

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
Hash As MemoryBlock

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
HexG As String (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
HexP As String (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
HexQ As String (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
HexX As String (read-only)

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

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HexY
HexY As String (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
LastErrorHtml As String (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
LastErrorText As String (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
LastErrorXml As String (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
LastMethodSuccess As Boolean
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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Signature
Signature As MemoryBlock

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
VerboseLogging As Boolean

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
Version As String (read-only)

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

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Methods

FromDer
Function FromDer(derData As MemoryBlock) As 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 FromDerFile(path As String) As 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 FromEncryptedPem(password As String, pemData As String) As 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 FromPem(pemData As String) As 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 FromPublicDer(derData As MemoryBlock) As 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 FromPublicDerFile(path As String) As Boolean

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

Returns True for success, False for failure.

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FromPublicPem
Function FromPublicPem(pemData As String) As 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 FromXml(xmlKey As String) As 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 GenKey(numBits As Int32) As 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 GenKeyFromParamsDer(derBytes As MemoryBlock) As 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 GenKeyFromParamsDerFile(path As String) As 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 GenKeyFromParamsPem(pem As String) As 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 GenKeyFromParamsPemFile(path As String) As 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 GetEncodedHash(encoding As String) As 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 Nil on failure

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GetEncodedSignature
Function GetEncodedSignature(encoding As String) As 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 Nil on failure

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LoadText
Function LoadText(path As String) As 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 Nil on failure

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SaveLastError
Function SaveLastError(path As String) As Boolean

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

Returns True for success, False for failure.

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SaveText
Function SaveText(strToSave As String, path As String) As 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 SetEncodedHash(encoding As String, encodedHash As String) As 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 SetEncodedSignature(encoding As String, encodedSig As String) As 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 SetEncodedSignatureRS(encoding As String, encodedR As String, encodedS As String) As 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 SetKeyExplicit(groupSizeInBytes As Int32, pHex As String, qHex As String, gHex As String, xHex As String) As 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 SetPubKeyExplicit(groupSizeInBytes As Int32, pHex As String, qHex As String, gHex As String, yHex As String) As 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 SignHash() As 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 ToDer() As MemoryBlock

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

Returns Nil on failure

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ToDerFile
Function ToDerFile(path As String) As 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 ToEncryptedPem(password As String) As String

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

Returns Nil on failure

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ToPem
Function ToPem() As String

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

Returns Nil on failure

More Information and Examples
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ToPublicDer
Function ToPublicDer() As MemoryBlock

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

Returns Nil on failure

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ToPublicDerFile
Function ToPublicDerFile(path As String) As 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 ToPublicPem() As String

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

Returns Nil on failure

More Information and Examples
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ToXml
Function ToXml(bPublicOnly As Boolean) As 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 Nil on failure

More Information and Examples
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UnlockComponent
Function UnlockComponent(unlockCode As String) As 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 Verify() As 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 VerifyKey() As 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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