Overview

digest.js is a javascript library implementing cryptographic digest, HMAC algorithms and Password-based Key Derivation Function.

digest.js is designed for modern web browsers and requires the W3C Typed Arrays support. digest.js has been successfully tested with these web browsers:

• Chrome 11
• Firefox 4 (WARNING: since Firefox does not support the Dataview API, you should use the David Flanagan’s emulation)
• Safari 5.1

Supported algorithms:

• digest
  • MD5
  • SHA-1
  • SHA-256
• Message Authentication Code (MAC)
  • HMAC/MD5
  • HMAC/SHA-1
  • HMAC/SHA-256
• Password-Based Key Derivation Function (PBKDF)
  • PBKDF1/SHA1
  • PBKDF1/MD5
  • PBKDF2/HMAC/SHA1
  • PBKDF2/HMAC/SHA-256

API Usage

Digest

1. Initialize a digest object

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var dg = new Digest.SHA1();

1. Update some data

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var data = new ArrayBuffer(3);
var buf = new Uint8Array(data);
buf[0] = 0x61; /* a */
buf[1] = 0x62; /* b */
buf[2] = 0x63; /* c */
dg.update(data);

1. Finalize

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var result = dg.finalize();

It is also possible to digest some data at once:

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var dg = new Digest.SHA1();
var result = dg.digest("abc");

MAC

1. Initialize a MAC object

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var mac = new Digest.HMAC_SHA1();

1. Set the key

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mac.setKey("KeyInPlainText");

1. Update some data

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var data = new ArrayBuffer(50);
var buf = new Uint8Array(data);
for (var i = 0; i < 50; i++) {
    buf[i] = 0xdd;
}
mac.update(data);

1. Finalize

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var result = mac.finalize();

PBKDF

1. Initialize a PBKDF object with the iteration count

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var pbkdf = new Digest.PBKDF_HMAC_SHA1(2048);

1. Derive key with the password, salt and desired key length (in bytes)

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var key = pbkdf.deriveKey("password", "salt", 24);

Misc

After the finalize, digest or mac methods have been called, the digest or mac object is automatically reset and can be reused.

The update, digest and mac methods accept these data types:

• ArrayBuffer
• String (US-ASCII encoding)
• byte (i.e. a number in the range 0-255)

The MAC setKey method accepts these data types:

• ArrayBuffer
• String (US-ASCII encoding)

The PBKDF deriveKey method accepts these data types for password and salt:

• ArrayBuffer
• String (US-ASCII encoding)

License

digest.js is released under the terms of the GNU GENERAL PUBLIC LICENSE Version 3