Dsa C# 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

Chilkat.Dsa obj = new Chilkat.Dsa();

Properties

DebugLogFilePath
public string DebugLogFilePath {get; set; }

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
public int GroupSize {get; set; }

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
public byte[] Hash {get; set; }

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
public string HexG {get; }

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
public string HexP {get; }

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
public string HexQ {get; }

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
public string HexX {get; }

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

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HexY
public string HexY {get; }

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
public string LastErrorHtml {get; }

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
public string LastErrorText {get; }

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
public string LastErrorXml {get; }

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
public bool LastMethodSuccess {get; set; }
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
public byte[] Signature {get; set; }

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
public bool VerboseLogging {get; set; }

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
public string Version {get; }

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

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Methods

FromDer
public bool FromDer(byte[] derData);

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

Returns true for success, false for failure.

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FromDerFile
public bool FromDerFile(string path);

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

Returns true for success, false for failure.

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FromEncryptedPem
public bool FromEncryptedPem(string password, string pemData);

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
public bool FromPem(string pemData);

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

Returns true for success, false for failure.

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FromPublicDer
public bool FromPublicDer(byte[] derData);

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
public bool FromPublicDerFile(string path);

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

Returns true for success, false for failure.

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FromPublicPem
public bool FromPublicPem(string pemData);

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

Returns true for success, false for failure.

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FromXml
public bool FromXml(string xmlKey);

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
public bool GenKey(int numBits);

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.

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GenKeyFromParamsDer
public bool GenKeyFromParamsDer(byte[] derBytes);

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
public bool GenKeyFromParamsDerFile(string path);

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
public bool GenKeyFromParamsPem(string pem);

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
public bool GenKeyFromParamsPemFile(string path);

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
public string GetEncodedHash(string encoding);

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
public string GetEncodedSignature(string encoding);

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
public string LoadText(string path);

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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SaveLastError
public bool SaveLastError(string path);

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
public bool SaveText(string strToSave, string path);

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
public bool SetEncodedHash(string encoding, string encodedHash);

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
public bool SetEncodedSignature(string encoding, string encodedSig);

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
public bool SetEncodedSignatureRS(string encoding, string encodedR, string encodedS);

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
public bool SetKeyExplicit(int groupSizeInBytes, string pHex, string qHex, string gHex, string xHex);

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
public bool SetPubKeyExplicit(int groupSizeInBytes, string pHex, string qHex, string gHex, string yHex);

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
public bool SignHash();

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.

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ToDer
public byte[] ToDer();

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

Returns an empty byte array on failure

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ToDerFile
public bool ToDerFile(string path);

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

Returns true for success, false for failure.

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ToEncryptedPem
public string ToEncryptedPem(string password);

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

Returns null on failure

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ToPem
public string ToPem();

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

Returns null on failure

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ToPublicDer
public byte[] ToPublicDer();

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

Returns an empty byte array on failure

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ToPublicDerFile
public bool ToPublicDerFile(string path);

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

Returns true for success, false for failure.

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ToPublicPem
public string ToPublicPem();

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

Returns null on failure

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ToXml
public string ToXml(bool bPublicOnly);

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

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UnlockComponent
public bool UnlockComponent(string unlockCode);

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
public bool Verify();

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.

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VerifyKey
public bool VerifyKey();

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

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