DSA Class
Properties Methods Events Configuration Settings Errors
The DSA (Digital Signature Algorithm) class enables users to generate DSA hash signatures.
Syntax
class ipworksencrypt.DSA
Remarks
The DSA (Digital Signature Algorithm) class 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 the Key* properties. To create a new key call create_key. Alternatively an existing certificate may be specified by setting the Certificate* properties
Signing
To sign data first set key or certificate. Select the input file by setting input_file or input_message. 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 create_key for details), file, and hash_signature to the recipient.
To sign a hash without recomputing the hash simply set hash_value to the pre-computed hash value before calling sign.
Signature Verification
To verify a signature specify the input data using input_file or input_message. Set signer_key or signer_cert. Next set hash_signature and call verify_signature. The verify_signature method will return True if the signature was successfully verified.
To verify a hash signature without recomputing the hash simply set hash_value to the pre-computed hash value before calling verify_signature.
Hash Notes
The class will determine whether or not to recompute the hash based on the properties that are set. If a file is specified by input_file or input_message the hash will be recomputed when calling sign or verify_signature. If the hash_value property is set the class will only sign the hash or verify the hash signature. Setting input_file or input_message clears the hash_value property. Setting the hash_value property clears the input file selection.
DSA Key Notes
A DSA key is made up of a number of individual parameters. When calling create_key the Key* properties are populated with a new private and public key.
After calling sign the public key must be sent to the recipient along with hash_signature so they may perform signature verification. Likewise you must obtain the public key along with hash_signature in order to perform signature verification.
The public key consists of the following parameters:
The class also includes the key_public_key property 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 key_public_key in which case the individual parameters must be sent.
The private key consists of the following parameters:
The class also include the key_private_key property 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 class with short descriptions. Click on the links for further details.
| cert_encoded | The certificate (PEM/base64 encoded). |
| cert_store | The name of the certificate store for the client certificate. |
| cert_store_password | If the certificate store is of a type that requires a password, this property is used to specify that password in order to open the certificate store. |
| cert_store_type | The type of certificate store for this certificate. |
| cert_subject | The subject of the certificate used for client authentication. |
| hash_algorithm | The hash algorithm used for hash computation. |
| hash_signature | The hash signature. |
| hash_value | The hash value of the data. |
| input_file | The file to process. |
| input_message | The message to process. |
| keyg | Represents the G parameter for the DSA algorithm. |
| keyp | Represents the P parameter for the DSA algorithm. |
| key_private_key | This property is a PEM formatted private key. |
| key_public_key | This property is a PEM formatted public key. |
| keyq | Represents the Q parameter for the DSA algorithm. |
| keyx | Represents the X parameter for the DSA algorithm. |
| keyy | Represents the Y parameter for the DSA algorithm. |
| signer_cert_encoded | The certificate (PEM/base64 encoded). |
| signer_cert_store | The name of the certificate store for the client certificate. |
| signer_cert_store_password | If the certificate store is of a type that requires a password, this property is used to specify that password in order to open the certificate store. |
| signer_cert_store_type | The type of certificate store for this certificate. |
| signer_cert_subject | The subject of the certificate used for client authentication. |
| signer_keyg | Represents the G parameter for the DSA algorithm. |
| signer_keyp | Represents the P parameter for the DSA algorithm. |
| signer_key_public_key | This property is a PEM formatted public key. |
| signer_keyq | Represents the Q parameter for the DSA algorithm. |
| signer_keyy | Represents the Y parameter for the DSA algorithm. |
| use_hex | Whether HashValue and HashSignature are hex encoded. |
Method List
The following is the full list of the methods of the class with short descriptions. Click on the links for further details.
| config | Sets or retrieves a configuration setting. |
| create_key | Creates a new key. |
| reset | Resets the class. |
| sign | Creates a hash signature. |
| verify_signature | Verifies the signature for the specified data. |
Event List
The following is the full list of the events fired by the class with short descriptions. Click on the links for further details.
| on_error | Information about errors during data delivery. |
| on_progress | Fired as progress is made. |
Configuration Settings
The following is a list of configuration settings for the class with short descriptions. Click on the links for further details.
| HashSignatureFormat | The format of the HashSignature. |
| KeyFormat | How the public and private key are formatted. |
| KeySize | The size, in bits, of the secret key. |
| BuildInfo | Information about the product's build. |
| CodePage | The system code page used for Unicode to Multibyte translations. |
| LicenseInfo | Information about the current license. |
| ProcessIdleEvents | Whether the class uses its internal event loop to process events when the main thread is idle. |
| SelectWaitMillis | The length of time in milliseconds the class will wait when DoEvents is called if there are no events to process. |
| UseInternalSecurityAPI | Tells the class whether or not to use the system security libraries or an internal implementation. |