Rsa Excel Class Module Reference Documentation

Rsa

Current Version: 9.5.0.79

RSA encryption component / library. Encrypt and decrypt byte arrays and strings. Generate public/private key pairs from 384 to 4096 bits in length. Import and export RSA keys. Import keys from SNK files. Input/output in raw binary, base64, hex encoding, quoted-printable, URL-encoding, etc.

Object Creation

Dim oRsa As Chilkat.Rsa
Set oRsa = Chilkat.NewRsa

Properties

Charset
Charset As String

This property only applies when encrypting, decrypting, signing, or verifying signatures for strings. When encrypting strings, the input string is first converted to this charset before encrypting.

When decrypting, the decrypted data is interpreted as a string with this charset encoding and converted to the appropriate return. For example, ActiveX's returning strings always return Unicode (2 bytes/char). Java strings are utf-8. Chilkat C++ strings are ANSI or utf-8. .NET strings are Unicode.

The default value of this property is the ANSI charset of the local computer.

When signing string data, the input string is first converted to this charset before being hashed and signed. When verifying the signature for string data, the input string is first converted to this charset before the verification process begins.

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DebugLogFilePath
DebugLogFilePath As String

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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EncodingMode
EncodingMode As String

Encoding mode to be used in methods ending in "ENC", such as EncryptStringENC. Valid EncodingModes are "base64", "hex", "url", or "quoted-printable" (or "qp"). Encryption methods ending in "ENC" will return encrypted data as a string encoded according to this property's value. Decryption methods ending in "ENC" accept an encoded string as specified by this property. The string is first decoded and then decrypted. The default value is "base64".

This property also applies to the "ENC" methods for creating and verifying digital signatures.

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LastErrorHtml
LastErrorHtml As String (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.

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LastErrorText
LastErrorText As String (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.

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LastErrorXml
LastErrorXml As String (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.

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LastMethodSuccess
LastMethodSuccess As Long
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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LittleEndian
LittleEndian As Long

The default value is False, which means that signatures and encrypted output will be created using the big endian byte ordering. A value of True will produce little-endian output, which is what Microsoft's Crypto API produces.

Important: Prior to v9.5.0.49, this property behaved the opposite as it should for encryption. When updating from an older version of Chilkat to v9.5.0.49 or greater, the following change is required:

  • If the application did NOT explicity set the LittleEndian property, then no change is required for encryption/decryption. If signatures were being created or verified, then explicitly set this property to True.
  • If the application explicitly set this property, then reverse the setting ONLY if doing encryption/decryption. No changes are required if doing signature creation/verification.

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NoUnpad
NoUnpad As Long

If True, skips unpadding when decrypting. The default is False. This property value is typically left unchanged.

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NumBits
NumBits As Long (read only)

The number of bits of the key generated or imported into this RSA encryption object. Keys ranging in size from 384 bits to 4096 bits can be generated by calling GenerateKey. A public or private key may be imported by calling ImportPublicKey or ImportPrivateKey. A key must be available either via GenerateKey or import before any of the encrypt/decrypt methods may be called.

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OaepHash
OaepHash As String
Introduced in version 9.5.0.48

Selects the hash algorithm for use within OAEP padding. The valid choices are "sha1", "sha256", "sha384", "sha512", "md2", "md5", "haval", "ripemd128", "ripemd160","ripemd256", or "ripemd320". The default is "sha1".

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OaepMgfHash
OaepMgfHash As String
Introduced in version 9.5.0.71

Selects the MGF (mask generation) hash algorithm for use within OAEP padding. The valid choices are "sha1", "sha256", "sha384", "sha512", "md2", "md5", "haval", "ripemd128", "ripemd160","ripemd256", or "ripemd320". The default is "sha1".

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OaepPadding
OaepPadding As Long

Controls whether Optimal Asymmetric Encryption Padding (OAEP) is used for the padding scheme (for encrypting/decrypting). If set to False, PKCS1 v1.5 padding is used. If set to True, PKCS1 v2.0 (OAEP) padding is used.

Important: The OAEP padding algorithm uses randomly generated bytes. Therefore, the RSA result will be different each time, even if all of the other inputs are identical. For example, if you RSA encrypt or sign the same data using the same key 100 times, the output will appear different each time, but they are all valid.

When creating digital signatures, this property controls whether RSA-PSS or PKCS1 v1.5 is used. If True, then the RSA-PSS signature scheme is used. The default value of this property is False.

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VerboseLogging
VerboseLogging As Long

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
Version As String (read only)

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

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Methods

DecryptBd
DecryptBd(bd As BinData, usePrivateKey As Boolean) As Long
Introduced in version 9.5.0.76

RSA decrypts the contents of bd. usePrivateKey should be set to True if the private key is to be used for decrypting. Otherwise it should be set to False if the public key is to be used for decrypting.

Important: If trying to match OpenSSL results, set the LittleEndian property = False.

Returns True for success, False for failure.

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DecryptStringENC
DecryptStringENC(encodedSig As String, usePrivateKey As Boolean) As String

Same as DecryptString, except the input is an encoded string. The encoding is specified by the EncodingMode property, which can have values such as "base64", "hex", "quoted-printable", "url", etc.

Important: If trying to match OpenSSL results, set the LittleEndian property = False.

Returns Nothing on failure

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EncryptBd
EncryptBd(bd As BinData, usePrivateKey As Boolean) As Long
Introduced in version 9.5.0.76

RSA encrypts the contents of bd. usePrivateKey should be set to True if the private key is to be used for encrypting. Otherwise it should be set to False if the public key is to be used for encrypting.

Important: If trying to match OpenSSL results, set the LittleEndian property = False.

Note: Except for special situations, the public key should always be used for encrypting, and the private key for decrypting. This makes sense because an encrypted message is sent to a recipient, and the recipient is the only one in possession of the private key, and therefore the only one that can decrypt and read the message.

Returns True for success, False for failure.

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EncryptStringENC
EncryptStringENC(str As String, bUsePrivateKey As Boolean) As String

Same as EncryptString, except the output is an encoded string. The encoding is specified by the EncodingMode property, which can have values such as "base64", "hex", "quoted-printable", "url", etc.

Important: If trying to match OpenSSL results, set the LittleEndian property = False.

Note: Except for special situations, the public key should always be used for encrypting, and the private key for decrypting. This makes sense because an encrypted message is sent to a recipient, and the recipient is the only one in possession of the private key, and therefore the only one that can decrypt and read the message.

Returns Nothing on failure

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ExportPrivateKey
ExportPrivateKey() As String

Exports the private-key of an RSA key pair to XML format. This is typically called after generating a new RSA key via the GenerateKey method.

Returns Nothing on failure

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ExportPrivateKeyObj
ExportPrivateKeyObj() As PrivateKey
Introduced in version 9.5.0.40

Exports the private-key to a private key object. This is typically called after generating a new RSA key via the GenerateKey method. Once the private key object is obtained, it may be saved in a variety of different formats.

Returns Nothing on failure

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ExportPublicKey
ExportPublicKey() As String

Exports the public-key of an RSA key pair to XML format. This is typically called after generating a new RSA key via the GenerateKey method.

Returns Nothing on failure

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ExportPublicKeyObj
ExportPublicKeyObj() As PublicKey
Introduced in version 9.5.0.40

Exports the public key to a public key object. Once the public key object is obtained, it may be saved in a variety of different formats.

Returns Nothing on failure

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GenerateKey
GenerateKey(numBits As Long) As Long

Generates a new RSA public/private key pair. The number of bits can range from 512 to 8192. Typical key lengths are 1024, 2048, or 4096 bits. After successful generation, the public/private parts of the key can be exported to XML via the ExportPrivateKey and ExportPublicKey methods.

Note: Prior to version 9.5.0.49, the max key size was 4096 bits. Generating an 8192-bit RSA key takes a considerable amount of time and CPU processing power. There are no event callbacks or progress monitoring for RSA key generation. Calling this will block the thread until it returns.

Returns True for success, False for failure.

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ImportPrivateKey
ImportPrivateKey(xmlKey As String) As Long

Imports a private key from XML format. After successful import, the private key can be used to encrypt or decrypt. A private key (by definition) contains both private and public parts. This is because the public key consist of modulus and exponent. The private key consists of modulus, exponent, P, Q, DP, DQ, InverseQ, and D using base64 representation:

<RSAKeyValue>
  <Modulus>...</Modulus>
  <Exponent>...</Exponent>
  <P>...</P>
  <Q>...</Q>
  <DP>...</DP>
  <DQ>...</DQ>
  <InverseQ>...</InverseQ>
  <D>...</D>
</RSAKeyValue>

Important: The Rsa object can contain either a private key or a public key, but not both. Importing a private key overwrites the existing key regardless of whether the type of key is public or private.

Returns True for success, False for failure.

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ImportPrivateKeyObj
ImportPrivateKeyObj(key As PrivateKey) As Long
Introduced in version 9.5.0.40

Imports a private key from a private key object. The imported private key is used in methods that sign or decrypt.

Returns True for success, False for failure.

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ImportPublicKey
ImportPublicKey(xmlKey As String) As Long

Imports a public key from XML format. After successful import, the public key can be used to encrypt or decrypt.

Note: Importing a public key overwrites the key that is currently contained in this object - even if it's a private key.

A public key consists of modulus and exponent using base64 representation:

<RSAPublicKey>
  <Modulus>...</Modulus>
  <Exponent>...</Exponent>
</RSAPublicKey>

Important: The Rsa object can contain either a private key or a public key, but not both. Importing a private key overwrites the existing key regardless of whether the type of key is public or private.

Returns True for success, False for failure.

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ImportPublicKeyObj
ImportPublicKeyObj(key As PublicKey) As Long
Introduced in version 9.5.0.40

Imports a public key from a public key object. The imported public key is used in methods that encrypt data or verify signatures.

Returns True for success, False for failure.

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OpenSslSignBd
OpenSslSignBd(bd As BinData) As Long
Introduced in version 9.5.0.77

Duplicates OpenSSL's rsautl utility for creating RSA signatures. The contents of bd are signed. If successful, the result is that bd contains the RSA signature that itself contains (embeds) the original data.

Returns True for success, False for failure.

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OpenSslSignStringENC
OpenSslSignStringENC(str As String) As String

Duplicates OpenSSL's rsautl utility for creating RSA signatures. Input data is a string, and returns the signature as a string encoded according to the EncodingMode property (base64, hex, etc.).

Returns Nothing on failure

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OpenSslVerifyBd
OpenSslVerifyBd(bd As BinData) As Long
Introduced in version 9.5.0.77

Duplicates OpenSSL's rsautl utility for verifying RSA signatures and recovering the original data. On input, the bd contains the RSA signature that embeds the original data. If successful (i.e. the signature was verified), then the bd is transformed to contain just the original data.

Returns True for success, False for failure.

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OpenSslVerifyStringENC
OpenSslVerifyStringENC(str As String) As String

Duplicates OpenSSL's rsautl utility for verifying RSA signatures and recovering the original data. Input data is a signature string encoded according to the EncodingMode property (base64, hex, etc.). Returns the original string.

Returns Nothing on failure

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SetX509Cert
SetX509Cert(cert As Cert, usePrivateKey As Boolean) As Long
Introduced in version 9.5.0.73

Provides the private or public key indirectly through a certificate. This method is especially useful on Windows computers where the private key is installed as non-exportable (such as on a hardware token).

Returns True for success, False for failure.

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SignBd
SignBd(bdData As BinData, hashAlgorithm As String, bdSig As BinData) As Long
Introduced in version 9.5.0.77

Creates an RSA digital signature by hashing the contents of bdData and then signing the hash. The hash algorithm is specified by hashAlgorithm, which may be "SHA-1", "MD5", "MD2", "SHA-256", "SHA-384", or "SHA-512". The resulting signature is returned in bdSig.

Important: If trying to match OpenSSL results, set the LittleEndian property = False. (The LittleEndian property should also be set to False to match Amazon web services, such as CloudFront.)

A private key is required to create digital signatures.

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SignHashENC
SignHashENC(encodedHash As String, hashAlg As String) As String

The same as SignBytesENC except the hash is passed directly.

Returns Nothing on failure

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SignStringENC
SignStringENC(strToBeHashed As String, hashAlgorithm As String) As String

Creates an RSA digital signature by hashing strToBeHashed and then signing the hash. The hash algorithm is specified by hashAlgorithm, which may be "SHA-1", "MD5", "MD2", "SHA-256", "SHA-384", or "SHA-512". The recommended hash algorithm is "SHA-1". The digital signature is returned as an encoded string, where the encoding is specified by the EncodingMode property.

Important: If trying to match OpenSSL results, set the LittleEndian property = False. (The LittleEndian property should also be set to False to match Amazon web services, such as CloudFront.)

A private key is required to create a digital signature.

An error is indicated when null reference is returned.

Returns Nothing on failure

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SnkToXml
SnkToXml(filename As String) As String

Imports a .snk file to an XML document that can be imported via the ImportPrivateKey method.

Returns Nothing on failure

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UnlockComponent
UnlockComponent(unlockCode As String) As Long

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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VerifyBd
VerifyBd(bdData As BinData, hashAlgorithm As String, bdSig As BinData) As Long
Introduced in version 9.5.0.77

Verifies an RSA digital signature. Returns True if the signature in bdSig is valid an confirms that the original data in bdData has not been modified. The hashAlgorithm may be "SHA-1", "MD5", "MD2", "SHA-256", "SHA-384", or "SHA-512".

Returns True for success, False for failure.

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VerifyHashENC
VerifyHashENC(encodedHash As String, hashAlg As String, encodedSig As String) As Long

The same as VerifyBytesENC except the hash of the original data is passed directly.

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VerifyPrivateKey
VerifyPrivateKey(xml As String) As Long

Returns True if the XML contains a valid RSA private key. Otherwise returns False.

Returns True for success, False for failure.

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VerifyStringENC
VerifyStringENC(originalString As String, hashAlgorithm As String, encodedSig As String) As Long

Verifies an RSA digital signature. Returns True if the signature is valid for the originalString. The hashAlgorithm may be "SHA-1", "MD5", "MD2", "SHA-256", "SHA-384", or "SHA-512". The recommended hash algorithm is "SHA-1".

The encodedSig is a digital signature encoded according to the EncodingMode property (i.e. base64, hex, etc.).

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