Dsa Lianja Reference Documentation

Dsa

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

loObject = createobject("CkDsa")

Properties

DebugLogFilePath As Character

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.

GroupSize As Numeric

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.

HexG As Character (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.

HexP As Character (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.

HexQ As Character (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.

HexX As Character (read-only)

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

HexY As Character (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.)

LastErrorHtml As Character (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.

LastErrorText As Character (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.

LastErrorXml As Character (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.

LastMethodSuccess As Boolean

Introduced in version 9.5.0.52

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

VerboseLogging As Boolean

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

Version As Character (read-only)

Version of the component/library, such as "9.4.1.42"

Methods

FromDerFile(path As Character) As Boolean

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

Returns .T. for success, .F. for failure.

Convert DSA DER Private Key to PEM

FromEncryptedPem(password As Character, pemData As Character) 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 .T. for success, .F. for failure.

FromPem(pemData As Character) As Boolean

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

Returns .T. for success, .F. for failure.

DSA Signature Create and Verify

FromPublicDerFile(path As Character) As Boolean

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

Returns .T. for success, .F. for failure.

FromPublicPem(pemData As Character) As Boolean

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

Returns .T. for success, .F. for failure.

FromXml(xmlKey As Character) As Boolean

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

Returns .T. for success, .F. for failure.

GenKey(numBits As Numeric) 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 .T. for success, .F. for failure.

DSA Generate Key

GenKeyFromParamsDerFile(path As Character) 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 .T. for success, .F. for failure.

Generate new DSA Key from OpenSSL Parameters File

GenKeyFromParamsPem(pem As Character) 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 .T. for success, .F. for failure.

GenKeyFromParamsPemFile(path As Character) 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 .T. for success, .F. for failure.

GetEncodedHash(encoding As Character) As Character

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 .T. for success, .F. for failure.

GetEncodedSignature(encoding As Character) As Character

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 .T. for success, .F. for failure.

LoadText(path As Character) As Character

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 .T. for success, .F. for failure.

SaveLastError(path As Character) As Boolean

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

Returns .T. for success, .F. for failure.

SaveText(strToSave As Character, path As Character) As Boolean

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

Returns .T. for success, .F. for failure.

SetEncodedHash(encoding As Character, encodedHash As Character) 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 .T. for success, .F. for failure.

SetEncodedSignature(encoding As Character, encodedSig As Character) 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 .T. for success, .F. for failure.

SetEncodedSignatureRS(encoding As Character, encodedR As Character, encodedS As Character) 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 .T. for success, .F. for failure.

SetKeyExplicit(groupSizeInBytes As Numeric, pHex As Character, qHex As Character, gHex As Character, xHex As Character) 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 .T. for success, .F. for failure.

SetPubKeyExplicit(groupSizeInBytes As Numeric, pHex As Character, qHex As Character, gHex As Character, yHex As Character) 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 .T. for success, .F. for failure.

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

Returns .T. for success, .F. for failure.

DSA Signature Create and Verify

ToDerFile(path As Character) As Boolean

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

Returns .T. for success, .F. for failure.

DSA Generate Key

ToEncryptedPem(password As Character) As Character

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

Returns .T. for success, .F. for failure.

DSA Generate Key

Convert DSA DER Private Key to PEM

ToPem() As Character

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

Returns .T. for success, .F. for failure.

Convert DSA DER Private Key to PEM

ToPublicDerFile(path As Character) As Boolean

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

Returns .T. for success, .F. for failure.

DSA Generate Key

ToPublicPem() As Character

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

Returns .T. for success, .F. for failure.

DSA Generate Key

ToXml(bPublicOnly As Boolean) As Character

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 .T. for success, .F. for failure.

DSA Generate Key

UnlockComponent(unlockCode As Character) As Boolean

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

Returns .T. for success, .F. for failure.

Diagnosing UnlockComponent Problems

UnlockComponent LastErrorText shows exact string passed to it.

Verify UnlockComponent Success w/ Permanent Unlock Code

LastErrorText Standard Information

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 .T. for success, .F. for failure.

DSA Signature Create and Verify

VerifyKey() As Boolean

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

DSA Signature Create and Verify