DSA Bean
Properties Methods Events Configuration Settings Errors
The DSA (Digital Signature Algorithm) component enables users to generate DSA hash signatures.
Syntax
IPWorksEncrypt.Dsa
Remarks
The DSA (Digital Signature Algorithm) bean enables users to generate DSA hash signatures.
To begin you must either specify an existing key or create a new key. Existing private keys may be specified by setting Key. To create a new key call CreateKey. Alternatively an existing certificate may be specified by setting Certificate
Signing
To sign data first set Key or Certificate. Select the input file by setting SetInputStream, InputFile, or InputMessage. Next call Sign. The Sign method will automatically compute the hash, and then sign the hash with the specified key.
Send the public key (see CreateKey for details), file, and HashSignature to the recipient.
To sign a hash without recomputing the hash simply set HashValue to the pre-computed hash value before calling Sign.
Signature Verification
To verify a signature specify the input data using InputFile or InputMessage. Set SignerKey or SignerCert. Next set HashSignature and call VerifySignature. The VerifySignature method will return True if the signature was successfully verified.
To verify a hash signature without recomputing the hash simply set HashValue to the pre-computed hash value before calling VerifySignature.
Hash Notes
The bean will determine whether or not to recompute the hash based on the properties that are set. If a file is specified by SetInputStream, InputFile, or InputMessage the hash will be recomputed when calling Sign or VerifySignature. If the HashValue property is set the bean will only sign the hash or verify the hash signature. Setting SetInputStream, InputFile, or InputMessage clears the HashValue property. Setting the HashValue property clears the input file selection.
DSA Key Notes
A DSA key is made up of a number of individual parameters. When calling CreateKey the Key property is populated with a new private and public key.
After calling Sign the public key must be sent to the recipient along with HashSignature so they may perform signature verification. Likewise you must obtain the public key along with HashSignature in order to perform signature verification.
The public key consists of the following parameters:
The bean also includes the PublicKey field which holds the PEM formatted public key for ease of use. This is helpful if you are in control of both signature creation and verification process. When sending the public key to a recipient note that not all implementations will support using the PEM formatted value in PublicKey in which case the individual parameters must be sent.
The private key consists of the following parameters:
The bean also include the PrivateKey field which holds the PEM formatted private key for ease of use. This is helpful for storing the private key more easily..Property List
The following is the full list of the properties of the bean with short descriptions. Click on the links for further details.
| Certificate | The certificate used for signing. |
| HashAlgorithm | The hash algorithm used for hash computation. |
| HashSignature | The hash signature. |
| HashValue | The hash value of the data. |
| InputFile | The file to process. |
| InputMessage | The message to process. |
| Key | The DSA key. |
| SignerCert | The certificate used for signature verification. |
| SignerKey | The public key used to verify the signature. |
| UseHex | Whether HashValue and HashSignature are hex encoded. |
Method List
The following is the full list of the methods of the bean with short descriptions. Click on the links for further details.
| config | Sets or retrieves a configuration setting . |
| createKey | Creates a new key. |
| reset | Resets the component. |
| setInputStream | Sets the stream from which the component will read data to encrypt or decrypt. |
| sign | Creates a hash signature. |
| verifySignature | Verifies the signature for the specified data. |
Event List
The following is the full list of the events fired by the bean with short descriptions. Click on the links for further details.
| Error | Information about errors during data delivery. |
| Progress | Fired as progress is made. |
Configuration Settings
The following is a list of configuration settings for the bean with short descriptions. Click on the links for further details.
| HashSignatureFormat | The format of the HashSignature. |
| KeySize | The size, in bits, of the secret key. |
| KeyFormat | How the public and private key are formatted. |
| CodePage | The system code page used for Unicode to Multibyte translations. |