struct Params [src]

Scrypt parameters

Fields

ln: u6The CPU/Memory cost parameter [ln] is log2(N).

r: u30The [r]esource usage parameter specifies the block size.

p: u30The [p]arallelization parameter. A large value of [p] can be used to increase the computational cost of scrypt without increasing the memory usage.

Members

fromLimits (Function)
interactive (Constant)
owasp (Constant)
sensitive (Constant)

Source

  pub const Params = struct {
    const Self = @This();

    /// The CPU/Memory cost parameter [ln] is log2(N).
    ln: u6,

    /// The [r]esource usage parameter specifies the block size.
    r: u30,

    /// The [p]arallelization parameter.
    /// A large value of [p] can be used to increase the computational cost of scrypt without
    /// increasing the memory usage.
    p: u30,

    /// Baseline parameters for interactive logins
    pub const interactive = Self.fromLimits(524288, 16777216);

    /// Baseline parameters for offline usage
    pub const sensitive = Self.fromLimits(33554432, 1073741824);

    /// Recommended parameters according to the
    /// [OWASP cheat sheet](https://cheatsheetseries.owasp.org/cheatsheets/Password_Storage_Cheat_Sheet.html).
    pub const owasp = Self{ .ln = 17, .r = 8, .p = 1 };

    /// Create parameters from ops and mem limits, where mem_limit given in bytes
    pub fn fromLimits(ops_limit: u64, mem_limit: usize) Self {
        const ops = @max(32768, ops_limit);
        const r: u30 = 8;
        if (ops < mem_limit / 32) {
            const max_n = ops / (r * 4);
            return Self{ .r = r, .p = 1, .ln = @as(u6, @intCast(math.log2(max_n))) };
        } else {
            const max_n = mem_limit / (@as(usize, @intCast(r)) * 128);
            const ln = @as(u6, @intCast(math.log2(max_n)));
            const max_rp = @min(0x3fffffff, (ops / 4) / (@as(u64, 1) << ln));
            return Self{ .r = r, .p = @as(u30, @intCast(max_rp / @as(u64, r))), .ln = ln };
        }
    }
}  