oidc-lib/src/claimer_sts/wallet_key_type.js

A library for creating OIDC Service Providers

class wallet_key_type {
	constructor (){
		this.keyTypeDefs = [
			// [ keytType, alg, crv, signature_alg, multicodec, multicodec_bytes ]
			[ 'RSA', 'RS256', null, null, null, null ],
			[ 'oct', 'A128GCM', null, null, null, null ],
			[ 'EC', 'ECDSA', 'P-256', 'ES256', [0x12, 0x00 ], null], 
			[ 'EC', 'ECDSA', 'P-384', 'ES384', [0x12, 0x01 ], null ], 
			[ 'EC', 'ECDSA', 'P-512', 'ES512', [0x12, 0x02 ], null ], 
			[ 'OKP', 'EdDSA', 'Ed25519', 'Ed25519', [0xed], null ],
			[ 'OKP', 'EdDSA', 'X25519', null, [0xec], null ],
		];

		for (var i=0; i < this.keyTypeDefs.length; i++){
			this.keyTypeDefs[i][5] = this.calculate_multicodec(i);
		}
	}

	getKeyParams(properties){
		var keyParams = {};
		var keyTypeDef;
		var target = new Array(null, null, null, null, null, null); 
		var indices = {
			'kty': 0,
			'alg': 1,
			'crv': 2,
			'signature_alg': 3,
			'multicodec': 4,
			'multicodec_bytes': 5
		}

		for (var key in properties){
			var index = indices[key];
			if (index === undefined){
				throw('undefined key property in getKeyParams: ' + key);
			}
			if (properties[key] !== undefined){
				target[index] = properties[key];
			}
		}

		for (var i in this.keyTypeDefs){
			keyTypeDef = this.keyTypeDefs[i];
			var match = true;
			for (var j=0; j < target.length; j++){
				if (target[j] === null){
					continue;
				}

				if (Array.isArray(target[j]) && Array.isArray(keyTypeDef[j])){
					var targA = target[j];
					var typeA = keyTypeDef[j];
					var kmatch = true;
					if (targA.length === typeA.length){
						for (var k=0; k<targA.length; k++){
							if (targA[k] === typeA[k]){
								continue;
							}
							else{
								kmatch = false;
								break;
							}
						}

						if (kmatch){
							continue;
						}
					}
				}
				else{
					if (target[j] === keyTypeDef[j]){
						continue;
					}
				}

				match = false;
				break;
			}

			if (match){
				for (var index in indices){
					if (keyTypeDef[indices[index]]){
						keyParams[index] = keyTypeDef[indices[index]];
					}
				}

				return keyParams;
			}
		}
	}


	// brute force
	calculate_multicodec(offsetOrMulticodec){
		if (typeof offsetOrMulticodec == 'number'){
			var multicodec_array = this.keyTypeDefs[offsetOrMulticodec][4];
			if (multicodec_array === null){
				return;
			}
			var input = Uint8Array.from(multicodec_array);
			if (!input.length){
				return;
			}
		}
		else{
			input = offsetOrMulticodec;
		}

		var output = new Uint8Array(9);
		var o = 0;
		var i = input.length - 1;
		var omask = 1;
		var imask = 1;
		while (i >= 0){
			while (imask < 0x100 && omask < 0x80){
				var bit = imask & input[i] ? omask : 0;
				output[o] |= bit;
				imask = imask << 1;
				omask = omask << 1;
			} 
			if (omask == 0x80){
				output[o] |= 0x80;
				o++;
				omask = 1;
			}
			if (imask == 0x100){
				i--;
				imask = 1;
				continue;
			}
		}
		if (output[o] == 0){
		  if (o == 0){
		    throw ("internal error in calculate_multicodec");
		  } 
		  else{
          // elide unnecessary LSB if zero
			o--;
			output[o] &= 0x7f;
		  }
		}
		var result = new Uint8Array(++o);
		for (var i=0; i<o; i++){
			result[i] = output[i];
		}
		return result;
	}
}

module.exports = {
	wallet_key_type: wallet_key_type
};