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Installation

dotnet add package Blindfold.Sdk
Zero external dependencies — uses only built-in .NET libraries (System.Text.Json). Targets net6.0, net8.0, and netstandard2.1.

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Quick Start (Local Mode)

No API key needed — runs entirely in-process with 86 regex-based entity types. 
using Blindfold.Sdk;

using var client = new BlindfoldClient();  // no API key needed

var result = await client.DetectAsync("Email john@acme.com, SSN 123-45-6789");

foreach (var entity in result.DetectedEntities)
{
    Console.WriteLine($"{entity.Type}: {entity.Text}");
}
// Email Address: john@acme.com
// Social Security Number: 123-45-6789

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Cloud API Setup

For NLP-powered detection (names, addresses, organizations), compliance policies, and audit logs: 
using Blindfold.Sdk;

// Simple initialization
using var client = new BlindfoldClient("your-api-key");

// Full configuration
using var client = new BlindfoldClient(new BlindfoldOptions
{
    ApiKey = "your-api-key",
    Region = "eu",                          // "eu" (default) or "us"
    MaxRetries = 3,
    Timeout = TimeSpan.FromSeconds(30),
    UserId = "user-123",                    // optional user tracking
});

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Methods

All methods are async with Async suffix and accept an optional CancellationToken parameter. The client implements IDisposable.

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DetectAsync

Identify PII without modifying the text. 
var result = await client.DetectAsync("Contact John Doe at john@example.com");

Console.WriteLine(result.EntitiesCount);  // 2

foreach (var entity in result.DetectedEntities)
{
    Console.WriteLine($"{entity.Type}: {entity.Text} ({entity.Score:F2})");
}

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TokenizeAsync / Detokenize

Replace PII with reversible tokens, then restore. 
// Tokenize
var response = await client.TokenizeAsync(
    "Contact John Doe at john@example.com"
);

Console.WriteLine(response.Text);
// "Contact <Person_1> at <Email Address_1>"

Console.WriteLine(response.Mapping);
// {<Person_1>: John Doe, <Email Address_1>: john@example.com}

// Detokenize (sync — runs client-side, no API call)
var original = client.Detokenize(
    response.Text,
    response.Mapping
);

Console.WriteLine(original.Text);
// "Contact John Doe at john@example.com"

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RedactAsync

Permanently remove PII from text. 
var result = await client.RedactAsync(
    "Patient Jane Smith, SSN: 123-45-6789"
);

Console.WriteLine(result.Text);
// "Patient , SSN: "

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MaskAsync

Partially hide PII while keeping some characters visible. 
var result = await client.MaskAsync(
    "Card: 4532-7562-9102-3456",
    charsToShow: 4,       // chars to show
    fromEnd: true,         // from end
    maskChar: "*",         // masking character
    entities: null         // entities filter (null = all)
);

Console.WriteLine(result.Text);
// "Card: ***************3456"

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HashAsync

Create deterministic identifiers for analytics. 
var result = await client.HashAsync(
    "User john@example.com purchased item",
    hashType: "SHA-256",    // hash type
    prefix: "user_",        // prefix
    hashLength: 16,         // hash length
    entities: null           // entities filter
);

Console.WriteLine(result.Text);
// "User user_a3f8b9c2d4e5f6g7 purchased item"

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EncryptAsync

Encrypt PII using AES-256. 
var result = await client.EncryptAsync(
    "API Key: sk-1234567890abcdef",
    "your-secure-key-min-16-chars"
);

Console.WriteLine(result.Text);
// "API Key: gAAAAABh3K7x..."

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SynthesizeAsync

Replace PII with realistic fake data. 
var result = await client.SynthesizeAsync(
    "John Doe lives in New York",
    language: "en",    // language
    entities: null     // entities filter
);

Console.WriteLine(result.Text);
// "Michael Smith lives in Boston" (example - will vary)

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Batch Processing

Process multiple texts in a single call. 
var texts = new[]
{
    "Contact John Doe",
    "Email jane@example.com",
    "No PII here"
};

var result = await client.TokenizeBatchAsync(texts);

Console.WriteLine(result.Total);      // 3
Console.WriteLine(result.Succeeded);  // 3

foreach (var item in result.Results)
{
    Console.WriteLine(item.Text);
}
All methods have batch variants: DetectBatchAsync, TokenizeBatchAsync, RedactBatchAsync, MaskBatchAsync, HashBatchAsync, EncryptBatchAsync, SynthesizeBatchAsync.

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Entity Filtering

Only detect specific entity types: 
var result = await client.DetectAsync(
    "John Doe, SSN 123-45-6789, email john@example.com",
    entities: new[] { "Social Security Number", "Email Address" }
);
// Only SSN and email detected, name is ignored

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Error Handling

using Blindfold.Sdk.Errors;

try
{
    var result = await client.TokenizeAsync("...");
}
catch (AuthenticationException ex)
{
    // Invalid API key (401)
    Console.Error.WriteLine("Invalid API key");
}
catch (ApiException ex)
{
    // API error (validation, rate limit, etc.)
    Console.Error.WriteLine($"API error {ex.StatusCode}");
}
catch (NetworkException ex)
{
    // Connection issues
    Console.Error.WriteLine($"Network error: {ex.Message}");
}

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Locales

Configure country-specific entity detection: 
using var client = new BlindfoldClient(new BlindfoldOptions
{
    Locales = new[] { "us", "de", "fr" }
});
Available locales: us, uk, eu, de, fr, es, it, pt, pl, cz, sk, ru, nl, ro, dk, se, no, be, at, ie, fi, hu, bg, hr, si, lt, lv, ee, ca, ch, au, nz, in, jp, kr, za, tr, il, ar, cl, co, br

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Source Code

GitHub Repository

Full source code, API reference, and additional examples.