peass-ng/PEASS-ng · error · ArgumentException

Invalid digest length (required: 1 - 64)

Error message

Invalid digest length (required: 1 - 64)

What it means

The Blake2bDigest(byte[] key, int digestLength, byte[] salt, byte[] personalization) constructor requires digestLength (in BYTES) to be between 1 and 64; otherwise it throws this ArgumentException. Unlike the bits-based constructor, this parameter is bytes, and the bounds match BLAKE2b's 1-64 byte output range.

Source

Thrown at winPEAS/winPEASexe/winPEAS/3rdParty/BouncyCastle/crypto/digests/Blake2bDigest.cs:189

            Init();
        }

        /**
         * Blake2b with key, required digest length (in bytes), salt and personalization.
         * After calling the doFinal() method, the key, the salt and the personal string
         * will remain and might be used for further computations with this instance.
         * The key can be overwritten using the clearKey() method, the salt (pepper)
         * can be overwritten using the clearSalt() method.
         *
         * @param key             A key up to 64 bytes or null
         * @param digestLength    from 1 up to 64 bytes
         * @param salt            16 bytes or null
         * @param personalization 16 bytes or null
         */
        public Blake2bDigest(byte[] key, int digestLength, byte[] salt, byte[] personalization)
        {
            if (digestLength < 1 || digestLength > 64)
                throw new ArgumentException("Invalid digest length (required: 1 - 64)");

            this.digestLength = digestLength;
            this.buffer = new byte[BLOCK_LENGTH_BYTES];

            if (salt != null)
            {
                if (salt.Length != 16)
                    throw new ArgumentException("salt length must be exactly 16 bytes");

                this.salt = new byte[16];
                Array.Copy(salt, 0, this.salt, 0, salt.Length);
            }
            if (personalization != null)
            {
                if (personalization.Length != 16)
                    throw new ArgumentException("personalization length must be exactly 16 bytes");

                this.personalization = new byte[16];

View on GitHub (pinned to 53fb989abc)

Solutions

1. Pass a byte length between 1 and 64 (use 64 for the full digest)
2. If you have a bit size, divide by 8 before constructing
3. Use Blake2bDigest() default constructor when the standard 64-byte output is wanted

Example fix

// before
var d = new Blake2bDigest(key, 512, salt, pers); // bits passed
// after
var d = new Blake2bDigest(key, 64, salt, pers); // bytes

bool IsValidBlake2bDigestBytes(int len) => len >= 1 && len <= 64;

When it happens

Trigger: new Blake2bDigest(key, digestLength, salt, personalization) with digestLength < 1 or > 64 (e.g. 0, 128, or a bit count like 512).

Common situations: Mixing the two constructors' units (passing 512 bits into the bytes-based constructor), zero/default-initialized length variables, ports from other BLAKE2 libraries that use bits.

Related errors

• BLAKE2b digest bit length must be a multiple of 8 and not gr
• Keys > 64 are not supported
• salt length must be exactly 16 bytes
• personalization length must be exactly 16 bytes
• BLAKE2s digest bit length must be a multiple of 8 and not gr

AI-assisted analysis of peass-ng/PEASS-ng@53fb989abc (2026-09-02). Data as JSON: /api/errors/819e7ba110401948. Report an issue: GitHub.