---
product: Chilkat
product_version: 11.7.0
language: delphix
language_label: Delphi ActiveX
class: SecureString
class_name: TChilkatSecureString
license: free
deprecated: false
reference_html: https://www.chilkatsoft.com/refdoc/delphiSecureStringRef.html
---
# Chilkat SecureString — Delphi ActiveX — v11.7.0

> Chilkat 11.7.0 · language=delphix · class=SecureString (TChilkatSecureString)
> Other versions: replace `11.7.0` in this URL. Other languages: `https://www.chilkatsoft.com/ai-docs/v/11.7.0/<lang>/classes/SecureString.md`.
> Language-wide rules (install, unlock, error model, strings/bytes): `https://www.chilkatsoft.com/ai-docs/v/11.7.0/delphix/guide.md`.

## Purpose

**Store, append, compare, hash, verify, and securely access sensitive string values.**

`Chilkat.SecureString` holds sensitive text in an encrypted in-memory form while still allowing controlled operations on the value. It can append clear-text strings, append text from a `StringBuilder`, append another `SecureString`, load text from a file, return the clear-text value when needed, compare secure strings, mark the value read-only, maintain a hash of the current value, and verify a supplied hash against that maintained value.

**Encrypted in-memory value**

Store sensitive text in a form that is decrypted only when needed for access, modification, comparison, or hashing.

**Append safely**

Append clear-text strings, `StringBuilder` content, or another `SecureString`; the value is then re-encrypted.

**Read-only protection**

Set `ReadOnly` to prevent later modification of the secure string.

**Hash maintenance**

Set `MaintainHash` to a supported hash algorithm such as `sha256`, `sha512`, `sha1`, or `md5`.

**Hash output and verification**

Retrieve the current hash value in an encoding such as hex or Base64, or verify a supplied encoded hash with `VerifyHash`.

**Compare and access**

Compare two secure strings with `SecStrEquals`, or call `Access` when the clear-text value is required.

**Common pattern:** Create a `SecureString`, load or append the sensitive text, set `MaintainHash` if later verification is needed, and optionally set `ReadOnly` after the final value is established. Use `Access` only at the point where the clear-text string is actually needed, and check `LastErrorText` if an append, file load, hash, or verification operation fails.

**Hash note:** `VerifyHash` depends on `MaintainHash` having already been set so the object maintains an internal hash for the current secure string value.

## Object creation, unlocking and error handling

**Object Creation**

```pascal
var
obj: TChilkatSecureString;
...
begin
obj := TChilkatSecureString.Create(Self);
...
// When finished, free the object instance.
obj.Free();
```

Call `Global.UnlockBundle` once at the start of the program, before using this or any other Chilkat class. Any string unlocks a fully functional 30-day trial; a purchased unlock code is used in production. See `guide.md` for the exact code in Delphi ActiveX.

How failure is reported depends on the method's return type and is stated in the note under each method below. In every case the diagnostic text is in the `LastErrorText` property of the object whose method was called.

## Members common to every Chilkat class

Documented once per language in `common-members.md`; listed here so this page is self-contained.

| Property | Signature | Access | Meaning |
|---|---|---|---|
| `DebugLogFilePath` | `property DebugLogFilePath: WideString` | read/write | If set to a file path, this property logs the LastErrorText of each Chilkat method or property call to the specified file. |
| `LastBinaryResult` | `property LastBinaryResult: OleVariant readonly` | read-only | This property is mainly used in SQL Server stored procedures to retrieve binary data from the last method call that returned binary data. |
| `LastErrorHtml` | `property LastErrorHtml: WideString readonly` | read-only | Provides HTML-formatted information about the last called method or property. |
| `LastErrorText` | `property LastErrorText: WideString readonly` | read-only | Provides plain text information about the last called method or property. |
| `LastErrorXml` | `property LastErrorXml: WideString readonly` | read-only | Provides XML-formatted information about the last called method or property. |
| `LastMethodSuccess` | `property LastMethodSuccess: Integer` | read/write | Indicates the success or failure of the most recent method call: `1` means success, `0` means failure. |
| `LastStringResult` | `property LastStringResult: WideString readonly` | read-only | In SQL Server stored procedures, this property holds the string return value of the most recent method call that returns a string. |
| `LastStringResultLen` | `property LastStringResultLen: Integer readonly` | read-only | The length, in characters, of the string contained in the LastStringResult property. |
| `VerboseLogging` | `property VerboseLogging: Integer` | read/write | If set to `1`, then the contents of LastErrorText (or LastErrorXml, or LastErrorHtml) may contain more verbose information. |
| `Version` | `property Version: WideString readonly` | read-only | Version of the component/library, such as "10.1.0" |

## Member index

| Member | Kind | Signature |
|---|---|---|
| `MaintainHash` | property, read/write | `property MaintainHash: WideString` |
| `ReadOnly` | property, read/write | `property ReadOnly: Integer` |
| `Access` | method | `function Access(): WideString;` |
| `Append` | method | `function Append(str: WideString): Integer;` |
| `AppendSb` | method | `function AppendSb(sb: IChilkatStringBuilder): Integer;` |
| `AppendSecure` | method | `function AppendSecure(secStr: IChilkatSecureString): Integer;` |
| `HashVal` | method | `function HashVal(encoding: WideString): WideString;` |
| `LoadFile` | method | `function LoadFile(path: WideString; charset: WideString): Integer;` |
| `SecStrEquals` | method | `function SecStrEquals(secStr: IChilkatSecureString): Integer;` |
| `VerifyHash` | method | `function VerifyHash(hashVal: WideString; encoding: WideString): Integer;` |

## Properties

### SecureString.MaintainHash

`Chilkat 11.7.0 · delphix · SecureString · MaintainHash · property · read/write · since 9.5.0.71`

```pascal
property MaintainHash: WideString
```

If set to the name of a hash algorithm, then a hash of the current string value is maintained. This allows for the hash to be verified via the VerifyHash method. Possible hash algorithm names are `sha1`, `sha256`, `sha384`, `sha512`, `md5`, `md2`, `ripemd160`, `ripemd128`,`ripemd256`, and `ripemd320`.

### SecureString.ReadOnly

`Chilkat 11.7.0 · delphix · SecureString · ReadOnly · property · read/write · since 9.5.0.71`

```pascal
property ReadOnly: Integer
```

Can be set to `1` to make this secure string read-only (cannot be modified).

## Methods

### SecureString.Access

`Chilkat 11.7.0 · delphix · SecureString · Access · method · since 9.5.0.71`

```pascal
function Access(): WideString;
```

Returns the clear-text string value.

Returns a zero-length WideString on failure

### SecureString.Append

`Chilkat 11.7.0 · delphix · SecureString · Append · method · since 9.5.0.71`

```pascal
function Append(str: WideString): Integer;
```

Appends a clear-text string to this secure string. The in-memory data will be decrypted, the string will be appended, and then it will be re-encrypted. Can return `0` if the string has been marked as read-only via the ReadOnly property.

Returns 1 for success, 0 for failure.

### SecureString.AppendSb

`Chilkat 11.7.0 · delphix · SecureString · AppendSb · method · since 9.5.0.71`

```pascal
function AppendSb(sb: IChilkatStringBuilder): Integer;
```

Appends a clear-text string contained in a StringBuilder to this secure string. The in-memory data will be decrypted, the string will be appended, and then it will be re-encrypted. Can return `0` if the string has been marked as read-only via the ReadOnly property.

Returns 1 for success, 0 for failure.

### SecureString.AppendSecure

`Chilkat 11.7.0 · delphix · SecureString · AppendSecure · method · since 9.5.0.71`

```pascal
function AppendSecure(secStr: IChilkatSecureString): Integer;
```

Appends the contents of a secure string to this secure string. The in-memory data will be decrypted, the secure string will be appended, and then it will be re-encrypted. Can return `0` if this string has been marked as read-only via the ReadOnly property.

Returns 1 for success, 0 for failure.

### SecureString.HashVal

`Chilkat 11.7.0 · delphix · SecureString · HashVal · method · since 9.5.0.71`

```pascal
function HashVal(encoding: WideString): WideString;
```

Returns the hash value for the current value of this secure string. The `encoding` specifies the encoding to be used. It can be any of the binary encoding algorithms, such as `base64`, `hex`, and many more listed at [Chilkat Binary Encodings](https://www.chilkatsoft.com/binary_encodings.asp)

Returns a zero-length WideString on failure

### SecureString.LoadFile

`Chilkat 11.7.0 · delphix · SecureString · LoadFile · method · since 9.5.0.71`

```pascal
function LoadFile(path: WideString; charset: WideString): Integer;
```

Loads the contents of a file into this secure string. The current contents of this object are replaced with the new text from the file.

Returns 1 for success, 0 for failure.

### SecureString.SecStrEquals

`Chilkat 11.7.0 · delphix · SecureString · SecStrEquals · method · since 9.5.0.71`

```pascal
function SecStrEquals(secStr: IChilkatSecureString): Integer;
```

Returns `1` if the `secStr` equals the contents of this secure string.

Returns 1 for success, 0 for failure.

### SecureString.VerifyHash

`Chilkat 11.7.0 · delphix · SecureString · VerifyHash · method · since 9.5.0.71`

```pascal
function VerifyHash(hashVal: WideString; encoding: WideString): Integer;
```

Verifies the `hashVal` against the hash value stored for the current value of this secure string. The MaintainHash property must've previously been set for this secure string to maintain an internal hash. The `encoding` specifies the encoding of the `hashVal`. It can be any of the binary encoding algorithms, such as `base64`, `hex`, and many more listed at [Chilkat Binary Encodings](https://www.chilkatsoft.com/binary_encodings.asp)

Returns 1 for success, 0 for failure.

## Related classes

[`StringBuilder`](https://www.chilkatsoft.com/ai-docs/v/11.7.0/delphix/classes/StringBuilder.md)