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Reading these classes, i see some possible cleaning:
ThirtyTwoBitRegister>>leftRotateBy: bits
[...]
bitCount _ bits \\ 32.
bitCount < 0 ifTrue: [bitCount _ bitCount + 32].
This second line is useless, bits \\ 32 will be positive
(not the case of (bits rem: 32) if bits negative).
--------------------------------------------------
This algorithm could avoid duplicating lowBit:
DigitalSignatureAlgorithm>>logOfLargestPowerOfTwoDividing:
aStrictlyPositiveInteger
^aStrictlyPositiveInteger lowBit - 1
--------------------------------------------------
DigitalSignatureAlgorithm>>inverseOf: x mod: n
[...]
v _ x.
u _ n.
k _ 0.
[x even and: [n even and: [u > 0]]] whileTrue: [ "eliminate common
factors of two"
k _ k + 1.
u _ u bitShift: -1.
v _ v bitShift: -1].
This has not much sense.
Should be [u even and: [v even]] whileTrue: [...]
Or even better:
k := u lowBit min: v lowBit.
u := u >> k.
v := v >> k.
Or even better:
(u even and: [v even]) ifTrue: [self error: 'no inverse']
because a pair of integers {a. b} satisying
(2 * u) * a + ((2 * v) * b) = 1
will be hard to find...
(Algorithm uselessly repeat (n highBit * 2) bitShift: before obtaining
luckily this 'no inverse' result)
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