Dsa Classic ASP Reference Documentation
Dsa
Current Version: 11.6.0
Chilkat.Dsa
Create DSA key pairs and parameters for workflows that still require
DSA-based signing or verification.
Load and save private or public DSA keys in DER, PEM, encrypted PEM,
XML, component-based, and OpenSSL-compatible formats.
Create DSA signatures over message digests using a loaded private key
and the appropriate encoded hash input.
Verify DSA signatures using a public key, encoded hash, and signature
data.
Access DSA parameters and key components as hex-encoded SSH1-format
bignums for low-level interoperability scenarios.
Work with encoded hashes and signatures when applications need hex,
Base64, or other textual representations of binary values.
For an extended overview, see
Dsa Class Overview.
Generate, import, export, sign, and verify DSA keys and signatures.
Chilkat.Dsa is the Chilkat class for DSA key generation,
DSA key import/export, DSA hash signing, and DSA signature verification.
It supports private and public keys in DER, PEM, encrypted PEM, XML,
explicit component, and OpenSSL parameter workflows. It also exposes DSA key
components as hex-encoded SSH1-format bignums and provides helpers for
working with encoded hashes and signatures.
Generate DSA keys
Import and export keys
Sign hashes
Verify signatures
Key components
Encoded data helpers
Dsa to sign the hash with the private key or
verify the signature with the public key. For new protocol designs, consider
whether a more modern signature algorithm is preferred; use this class when
DSA is required for compatibility.
Object Creation
set dsa = Server.CreateObject("Chilkat.Dsa")
' ... use dsa ...
set dsa = NothingClassic ASP creates Chilkat objects with Server.CreateObject. The registered Chilkat ActiveX must match the bitness of the IIS application pool: a pool with Enable 32-Bit Applications set to True needs the 32-bit ActiveX, otherwise the 64-bit ActiveX. To bind to a specific major version of Chilkat, append the major version number to the ProgID, such as Server.CreateObject("Chilkat.Dsa.11") for Chilkat v11.*.*.
VBScript requires set when assigning an object, so the signatures on this page show set x = obj.Method(...) for methods that return a Chilkat object; test the result with Is Nothing, since a method that fails to return an object returns Nothing. A method with no return value is called as a statement without parentheses (obj.Method arg1, arg2). Boolean properties, arguments and return values are integers in the ActiveX: pass 1 or 0, and test success with = 1. Byte arrays are Variant arrays and can be sent with Response.BinaryWrite. Asynchronous (*Async) methods and event callbacks are not used from Classic ASP.
Properties
DebugLogFilePath
If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. This logging helps identify the context and history of Chilkat calls leading up to any crash or hang, aiding in debugging.
Enabling the VerboseLogging property provides more detailed information. This property is mainly used for debugging rare instances where a Chilkat method call causes a hang or crash, which should generally not happen.
Possible causes of hangs include:
- A timeout property set to 0, indicating an infinite timeout.
- A hang occurring within an event callback in the application code.
- An internal bug in the Chilkat code causing the hang.
GroupSize
Specifies the size, in bits, of the DSA subgroup parameter Q used by the legacy GenKey method. The default is 160. This also determines the natural size of the DSA signature components r and s.
Applications should normally leave this property at its default. When an explicit standards-era (L, N) parameter pair is required, use GenKey2, where L is the bit length of P and N is the bit length of Q.
Hash
Contains the message digest to be signed by SignHash or checked by Verify. Set this property before calling either method. The same value can also be supplied in encoded form with SetEncodedHash.
The Dsa class does not hash the original message. The application must compute the exact digest required by the protocol or file format and provide the resulting bytes here.
HexG
Returns the DSA domain parameter G, the generator of the subgroup of order Q modulo P.
The returned text is a hexadecimal encoding of Chilkat's SSH1-format bignum representation, which includes a two-byte bit-length prefix followed by the unsigned integer bytes.
topHexP
Returns the DSA domain parameter P, the large prime modulus.
The returned text is a hexadecimal encoding of Chilkat's SSH1-format bignum representation, which includes a two-byte bit-length prefix followed by the unsigned integer bytes.
topHexQ
Returns the DSA domain parameter Q, a prime divisor of P - 1. The bit length of Q is commonly written as N and determines the range of the private value X and signature components r and s.
The returned text is a hexadecimal encoding of Chilkat's SSH1-format bignum representation, which includes a two-byte bit-length prefix followed by the unsigned integer bytes.
topHexX
Returns the DSA private value X. It is present only when the object contains a private key and satisfies 0 < X < Q.
The returned text is a hexadecimal encoding of Chilkat's SSH1-format bignum representation, which includes a two-byte bit-length prefix followed by the unsigned integer bytes.
X can create signatures as the key owner. Do not log, transmit, or persist this value unless it is protected as private-key material.HexY
Returns the DSA public value Y, where Y = GX mod P. It is available when either a public or private DSA key is loaded.
The returned text is a hexadecimal encoding of Chilkat's SSH1-format bignum representation, which includes a two-byte bit-length prefix followed by the unsigned integer bytes.
topLastBinaryResult
This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. It is only accessible if Chilkat.Global.KeepBinaryResult is set to 1. This feature allows for the retrieval of large varbinary results in an SQL Server environment, which has restrictions on returning large data via method calls, though temp tables can handle binary properties.
LastErrorHtml
Provides HTML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastErrorText
Provides plain text information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
LastErrorXml
Provides XML-formatted information about the last called method or property. If a method call fails or behaves unexpectedly, check this property for details. Note that information is available regardless of the method call's success.
topLastMethodSuccess
Indicates the success or failure of the most recent method call: 1 means success, 0 means failure. This property remains unchanged by property setters or getters. This method is present to address challenges in checking for null or Nothing returns in certain programming languages. Note: This property does not apply to methods that return integer values or to boolean-returning methods where the boolean does not indicate success or failure.
LastStringResult
In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. It is accessible only when Chilkat.Global.KeepStringResult is set to TRUE. SQL Server has limitations on string lengths returned from methods and properties, but temp tables can be used to access large strings.
LastStringResultLen
The length, in characters, of the string contained in the LastStringResult property.
topSignature
Contains the DSA signature produced by SignHash. Before calling Verify, set this property to the signature being checked, or use SetEncodedSignature or SetEncodedSignatureRS.
Chilkat represents the signature as an ASN.1 DER SEQUENCE containing the two DSA integers r and s. Use GetEncodedSignature to obtain a hexadecimal or Base64 representation.
UncommonOptions
Reserved for uncommon or compatibility-specific options. The default is the empty string, and applications should normally leave this property unchanged unless Chilkat documentation or support identifies a specific keyword required for the target system.
topVerboseLogging
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.
Version
Methods
FromDer
Loads a DSA private key from the DER-encoded bytes in derData
Returns 1 for success, 0 for failure.
topFromDerBd
Loads a DSA private key from the DER bytes contained in the BinData object passed in bd1 on successful decoding.
BinData content contains secret key material and should be cleared or released when no longer needed.Returns 1 for success, 0 for failure.
topFromDerFile
Loads a DSA private key from the DER-encoded file specified by path1 when the file is read and decoded successfully; otherwise returns 0.
LastErrorText when loading fails.Returns 1 for success, 0 for failure.
FromEncryptedPem
Loads a DSA private key from the PEM text in pemDatapassword
Returns 1 on success and 0 if the PEM cannot be decoded, the password is incorrect, or the contained key is not a supported DSA private key.
Returns 1 for success, 0 for failure.
topFromPem
Loads an unencrypted DSA private key from the PEM text in pemData
FromEncryptedPem when password-protected PEM is available.Returns 1 for success, 0 for failure.
FromPublicDer
Loads a DSA public key from the DER-encoded bytes in derDataVerify and can be exported, but it cannot be used by SignHash.
Returns 1 for success, 0 for failure.
topFromPublicDerBd
Loads a DSA public key from the DER bytes contained in the BinData object passed in bd
Returns 1 for success, 0 for failure.
topFromPublicDerFile
Loads a DSA public key from the DER-encoded file specified by path1 when the file is read and decoded successfully; otherwise returns 0.
Returns 1 for success, 0 for failure.
topFromPublicPem
Loads a DSA public key from the PEM text in pemData1 when the PEM contains a supported DSA public key and is decoded successfully.
Returns 1 for success, 0 for failure.
topFromXml
Loads a DSA public or private key from the XML text in xmlKeyX.
X, it contains the complete private key and must be protected accordingly.Returns 1 for success, 0 for failure.
topGenKey
Generates a new DSA key pair with a P size of numBitsnumBitsGroupSize, whose default is 160 bits.
For explicit standard parameter pairs such as (2048, 224) or (3072, 256), use GenKey2.
Returns 1 for success, 0 for failure.
GenKey2
Generates a new DSA key pair using an explicit (L, N) parameter-size combination. keyLenBitsL, the bit length of the prime modulus P. modLenBitsN, the bit length of the subgroup prime Q.
| L | N | Historical FIPS 186-4 combination |
|---|---|---|
1024 | 160 | Legacy |
2048 | 224 or 256 | Supported parameter pairs |
3072 | 256 | Largest listed pair |
Returns 1 for success, 0 for failure.
topGenKeyFromParamsDer
Generates a new DSA key pair from OpenSSL-style DSA parameters supplied as DER-encoded bytes in derBytes
The supplied data contains DSA domain parameters P, Q, and G, not an existing private key. Chilkat validates or imports those parameters and generates a fresh private value X and corresponding public value Y.
Returns 1 for success, 0 for failure.
topGenKeyFromParamsDerBd
Generates a new DSA key pair from OpenSSL-style DSA parameters stored as DER bytes in the BinData object passed in bd
The supplied data contains DSA domain parameters P, Q, and G, not an existing private key. Chilkat validates or imports those parameters and generates a fresh private value X and corresponding public value Y.
Returns 1 for success, 0 for failure.
topGenKeyFromParamsDerFile
Generates a new DSA key pair from the OpenSSL-style DER DSA-parameters file specified by path
The supplied data contains DSA domain parameters P, Q, and G, not an existing private key. Chilkat validates or imports those parameters and generates a fresh private value X and corresponding public value Y.
Returns 1 when the parameters are loaded and a key pair is generated successfully.
Returns 1 for success, 0 for failure.
GenKeyFromParamsPem
Generates a new DSA key pair from OpenSSL-style DSA parameters supplied as PEM text in pem
The supplied data contains DSA domain parameters P, Q, and G, not an existing private key. Chilkat validates or imports those parameters and generates a fresh private value X and corresponding public value Y.
Returns 1 for success, 0 for failure.
topGenKeyFromParamsPemFile
Generates a new DSA key pair from the OpenSSL-style PEM DSA-parameters file specified by path
The supplied data contains DSA domain parameters P, Q, and G, not an existing private key. Chilkat validates or imports those parameters and generates a fresh private value X and corresponding public value Y.
A typical parameter file is PEM-armored with a BEGIN DSA PARAMETERS header. The newly generated private key can be exported with the applicable To* methods.
Returns 1 for success, 0 for failure.
topGenKeyFromPQG
Generates a new DSA private/public key pair using the preselected domain parameters P, Q, and G supplied in pHexqHexgHex
Each argument is hexadecimal text in Chilkat's SSH1-format bignum representation. Chilkat generates a fresh private value X and derives Y; the supplied values are domain parameters, not an existing key pair.
Returns 1 for success, 0 for failure.
topGetEncodedHash
Returns the current Hash bytes encoded according to encodinghex or base64.
This method does not compute a hash; it only converts the bytes already stored in the Hash property to text.
Returns Nothing on failure
GetEncodedSignature
Returns the current Signature bytes encoded according to encodinghex or base64.
After a successful SignHash call, the returned bytes are the ASN.1 DER-encoded DSA signature containing the integers r and s.
Returns Nothing on failure
LoadText
Loads the entire file specified by path
Returns Nothing on failure
SaveText
Writes strToSavepath1 on success.
Returns 1 for success, 0 for failure.
topSetEncodedHash
Decodes encodedHashencodingHash property. Use hex or base64.
The decoded value must be the already-computed message digest that will be signed by SignHash or checked by Verify.
Returns 1 for success, 0 for failure.
topSetEncodedSignature
Decodes the signature text in encodedSigencodingSignature property. Use hex or base64.
The decoded bytes are expected to contain the ASN.1 DER-encoded DSA signature. Set the corresponding Hash and public key before calling Verify.
Returns 1 for success, 0 for failure.
topSetEncodedSignatureRS
Builds the DSA signature from separately encoded r and s integer values. encodingencodedRencodedShex or base64.
On success, Signature contains the ASN.1 DER SEQUENCE of the two integers and is ready for use with Verify.
Returns 1 for success, 0 for failure.
topSetKeyExplicit
Loads a DSA private key from explicitly supplied components. groupSizeInBytesQ in bytes. pHexqHexgHexxHexP, Q, G, and the private value X, respectively.
The corresponding public value Y = GX mod P is derived from the private key.
xHex contains the private key. Do not expose it in logs or transmit it over an unprotected channel.Returns 1 for success, 0 for failure.
topSetPubKeyExplicit
Loads a DSA public key from explicitly supplied components. groupSizeInBytesQ in bytes. pHexqHexgHexyHexP, Q, G, and the public value Y, respectively.
The resulting object can verify DSA signatures but cannot create them.
Returns 1 for success, 0 for failure.
topSignHash
Creates a DSA signature over the digest currently stored in Hash. A DSA private key must be loaded, and the digest must be set directly or with SetEncodedHash before this method is called.
On success, Signature contains an ASN.1 DER-encoded sequence of the DSA values r and s. Retrieve it with GetEncodedSignature or read the Signature property.
Returns 1 for success, 0 for failure.
ToDer
Returns the loaded DSA private key as DER-encoded bytes. A private key must be present; a public-only key cannot be exported by this method.
Returns a zero-length byte array (as a Variant) on failure.
An empty array will have a UBound of -1 meaning 0 elements.
ToDerBd
Writes the DER-encoded DSA private key to the BinData object passed in bd1 on success.
Returns 1 for success, 0 for failure.
topToDerFile
Writes the loaded DSA private key to the DER file specified by path1 on success.
Returns 1 for success, 0 for failure.
ToEncryptedPem
Returns the loaded DSA private key as password-encrypted PEM text using password
Returns Nothing on failure
ToPem
Returns the loaded DSA private key as unencrypted PEM text.
ToEncryptedPem when password protection is required.Returns Nothing on failure
ToPublicDer
Returns the public portion of the loaded DSA key as DER-encoded bytes. This works whether the object contains a public key or a private key with a corresponding public value.
Returns a zero-length byte array (as a Variant) on failure.
An empty array will have a UBound of -1 meaning 0 elements.
ToPublicDerBd
Writes the DER-encoded public portion of the loaded DSA key to the BinData object passed in bd1 on success.
Returns 1 for success, 0 for failure.
topToPublicDerFile
Writes the public portion of the loaded DSA key to the DER file specified by path1 on success.
Returns 1 for success, 0 for failure.
ToPublicPem
Returns the public portion of the loaded DSA key as PEM text. Public-key PEM may be distributed to parties that need to verify signatures; it does not contain the private value X.
Returns Nothing on failure
ToXml
Returns the loaded DSA key as XML. Set bPublicOnly1 to export public components only. Set it to 0 to include the private component when a private key is loaded.
bPublicOnly0, the XML can contain the private value X. Protect it as private-key material.Returns Nothing on failure
Verify
Verifies the DSA signature currently stored in Signature against the digest stored in Hash, using the loaded public key. Both values must be set before calling this method.
Returns 1 only when the signature is valid. A 0 result can indicate an invalid signature, malformed input, an incompatible key, or another operational error; inspect LastErrorText when the reason matters.
Returns 1 for success, 0 for failure.
VerifyKey
Checks the mathematical validity and internal consistency of the DSA public or private key currently loaded in the object. Returns 1 when the key parameters and available key components pass validation.
This does not establish who owns the key, whether the key came from a trusted source, or whether it is suitable for a particular protocol.